source "drivers/staging/omap-thermal/Kconfig"
+source "drivers/staging/ramster/Kconfig"
+
endif # STAGING
obj-$(CONFIG_WIMAX_GDM72XX) += gdm72xx/
obj-$(CONFIG_CSR_WIFI) += csr/
obj-$(CONFIG_OMAP_BANDGAP) += omap-thermal/
+obj-$(CONFIG_ZCACHE2) += ramster/
--- /dev/null
+config ZCACHE2
+ bool "Dynamic compression of swap pages and clean pagecache pages"
+ depends on CRYPTO=y && SWAP=y && CLEANCACHE && FRONTSWAP && !ZCACHE
+ select CRYPTO_LZO
+ default n
+ help
+ Zcache2 doubles RAM efficiency while providing a significant
+ performance boosts on many workloads. Zcache2 uses
+ compression and an in-kernel implementation of transcendent
+ memory to store clean page cache pages and swap in RAM,
+ providing a noticeable reduction in disk I/O. Zcache2
+ is a complete rewrite of the older zcache; it was intended to
+ be a merge but that has been blocked due to political and
+ technical disagreements. It is intended that they will merge
+ again in the future. Until then, zcache2 is a single-node
+ version of ramster.
--- /dev/null
+zcache-y := zcache-main.o tmem.o zbud.o
+
+obj-$(CONFIG_ZCACHE2) += zcache.o
--- /dev/null
+
+/*
+ * zcache/ramster.h
+ *
+ * Placeholder to resolve ramster references when !CONFIG_RAMSTER
+ * Real ramster.h lives in ramster subdirectory.
+ *
+ * Copyright (c) 2009-2012, Dan Magenheimer, Oracle Corp.
+ */
+
+#ifndef _ZCACHE_RAMSTER_H_
+#define _ZCACHE_RAMSTER_H_
+
+#ifdef CONFIG_RAMSTER
+#include "ramster/ramster.h"
+#else
+static inline void ramster_init(bool x, bool y, bool z)
+{
+}
+
+static inline void ramster_register_pamops(struct tmem_pamops *p)
+{
+}
+
+static inline int ramster_remotify_pageframe(bool b)
+{
+ return 0;
+}
+
+static inline void *ramster_pampd_free(void *v, struct tmem_pool *p,
+ struct tmem_oid *o, uint32_t u, bool b)
+{
+ return NULL;
+}
+
+static inline int ramster_do_preload_flnode(struct tmem_pool *p)
+{
+ return -1;
+}
+
+static inline bool pampd_is_remote(void *v)
+{
+ return false;
+}
+
+static inline void ramster_count_foreign_pages(bool b, int i)
+{
+}
+
+static inline void ramster_cpu_up(int cpu)
+{
+}
+
+static inline void ramster_cpu_down(int cpu)
+{
+}
+#endif
+
+#endif /* _ZCACHE_RAMSTER_H */
--- /dev/null
+/*
+ * In-kernel transcendent memory (generic implementation)
+ *
+ * Copyright (c) 2009-2012, Dan Magenheimer, Oracle Corp.
+ *
+ * The primary purpose of Transcedent Memory ("tmem") is to map object-oriented
+ * "handles" (triples containing a pool id, and object id, and an index), to
+ * pages in a page-accessible memory (PAM). Tmem references the PAM pages via
+ * an abstract "pampd" (PAM page-descriptor), which can be operated on by a
+ * set of functions (pamops). Each pampd contains some representation of
+ * PAGE_SIZE bytes worth of data. For those familiar with key-value stores,
+ * the tmem handle is a three-level hierarchical key, and the value is always
+ * reconstituted (but not necessarily stored) as PAGE_SIZE bytes and is
+ * referenced in the datastore by the pampd. The hierarchy is required
+ * to ensure that certain invalidation functions can be performed efficiently
+ * (i.e. flush all indexes associated with this object_id, or
+ * flush all objects associated with this pool).
+ *
+ * Tmem must support potentially millions of pages and must be able to insert,
+ * find, and delete these pages at a potential frequency of thousands per
+ * second concurrently across many CPUs, (and, if used with KVM, across many
+ * vcpus across many guests). Tmem is tracked with a hierarchy of data
+ * structures, organized by the elements in the handle-tuple: pool_id,
+ * object_id, and page index. One or more "clients" (e.g. guests) each
+ * provide one or more tmem_pools. Each pool, contains a hash table of
+ * rb_trees of tmem_objs. Each tmem_obj contains a radix-tree-like tree
+ * of pointers, with intermediate nodes called tmem_objnodes. Each leaf
+ * pointer in this tree points to a pampd, which is accessible only through
+ * a small set of callbacks registered by the PAM implementation (see
+ * tmem_register_pamops). Tmem only needs to memory allocation for objs
+ * and objnodes and this is done via a set of callbacks that must be
+ * registered by the tmem host implementation (e.g. see tmem_register_hostops).
+ */
+
+#include <linux/list.h>
+#include <linux/spinlock.h>
+#include <linux/atomic.h>
+#ifdef CONFIG_RAMSTER
+#include <linux/delay.h>
+#endif
+
+#include "tmem.h"
+
+/* data structure sentinels used for debugging... see tmem.h */
+#define POOL_SENTINEL 0x87658765
+#define OBJ_SENTINEL 0x12345678
+#define OBJNODE_SENTINEL 0xfedcba09
+
+/*
+ * A tmem host implementation must use this function to register callbacks
+ * for memory allocation.
+ */
+static struct tmem_hostops tmem_hostops;
+
+static void tmem_objnode_tree_init(void);
+
+void tmem_register_hostops(struct tmem_hostops *m)
+{
+ tmem_objnode_tree_init();
+ tmem_hostops = *m;
+}
+
+/*
+ * A tmem host implementation must use this function to register
+ * callbacks for a page-accessible memory (PAM) implementation.
+ */
+static struct tmem_pamops tmem_pamops;
+
+void tmem_register_pamops(struct tmem_pamops *m)
+{
+ tmem_pamops = *m;
+}
+
+/*
+ * Oid's are potentially very sparse and tmem_objs may have an indeterminately
+ * short life, being added and deleted at a relatively high frequency.
+ * So an rb_tree is an ideal data structure to manage tmem_objs. But because
+ * of the potentially huge number of tmem_objs, each pool manages a hashtable
+ * of rb_trees to reduce search, insert, delete, and rebalancing time.
+ * Each hashbucket also has a lock to manage concurrent access and no
+ * searches, inserts, or deletions can be performed unless the lock is held.
+ * As a result, care must be taken to ensure tmem routines are not called
+ * recursively; the vast majority of the time, a recursive call may work
+ * but a deadlock will occur a small fraction of the time due to the
+ * hashbucket lock.
+ *
+ * The following routines manage tmem_objs. In all of these routines,
+ * the hashbucket lock is already held.
+ */
+
+/* Search for object==oid in pool, returns object if found. */
+static struct tmem_obj *__tmem_obj_find(struct tmem_hashbucket *hb,
+ struct tmem_oid *oidp,
+ struct rb_node **parent,
+ struct rb_node ***link)
+{
+ struct rb_node *_parent = NULL, **rbnode;
+ struct tmem_obj *obj = NULL;
+
+ rbnode = &hb->obj_rb_root.rb_node;
+ while (*rbnode) {
+ BUG_ON(RB_EMPTY_NODE(*rbnode));
+ _parent = *rbnode;
+ obj = rb_entry(*rbnode, struct tmem_obj,
+ rb_tree_node);
+ switch (tmem_oid_compare(oidp, &obj->oid)) {
+ case 0: /* equal */
+ goto out;
+ case -1:
+ rbnode = &(*rbnode)->rb_left;
+ break;
+ case 1:
+ rbnode = &(*rbnode)->rb_right;
+ break;
+ }
+ }
+
+ if (parent)
+ *parent = _parent;
+ if (link)
+ *link = rbnode;
+ obj = NULL;
+out:
+ return obj;
+}
+
+static struct tmem_obj *tmem_obj_find(struct tmem_hashbucket *hb,
+ struct tmem_oid *oidp)
+{
+ return __tmem_obj_find(hb, oidp, NULL, NULL);
+}
+
+static void tmem_pampd_destroy_all_in_obj(struct tmem_obj *, bool);
+
+/* Free an object that has no more pampds in it. */
+static void tmem_obj_free(struct tmem_obj *obj, struct tmem_hashbucket *hb)
+{
+ struct tmem_pool *pool;
+
+ BUG_ON(obj == NULL);
+ ASSERT_SENTINEL(obj, OBJ);
+ BUG_ON(obj->pampd_count > 0);
+ pool = obj->pool;
+ BUG_ON(pool == NULL);
+ if (obj->objnode_tree_root != NULL) /* may be "stump" with no leaves */
+ tmem_pampd_destroy_all_in_obj(obj, false);
+ BUG_ON(obj->objnode_tree_root != NULL);
+ BUG_ON((long)obj->objnode_count != 0);
+ atomic_dec(&pool->obj_count);
+ BUG_ON(atomic_read(&pool->obj_count) < 0);
+ INVERT_SENTINEL(obj, OBJ);
+ obj->pool = NULL;
+ tmem_oid_set_invalid(&obj->oid);
+ rb_erase(&obj->rb_tree_node, &hb->obj_rb_root);
+}
+
+/*
+ * Initialize, and insert an tmem_object_root (called only if find failed).
+ */
+static void tmem_obj_init(struct tmem_obj *obj, struct tmem_hashbucket *hb,
+ struct tmem_pool *pool,
+ struct tmem_oid *oidp)
+{
+ struct rb_root *root = &hb->obj_rb_root;
+ struct rb_node **new = NULL, *parent = NULL;
+
+ BUG_ON(pool == NULL);
+ atomic_inc(&pool->obj_count);
+ obj->objnode_tree_height = 0;
+ obj->objnode_tree_root = NULL;
+ obj->pool = pool;
+ obj->oid = *oidp;
+ obj->objnode_count = 0;
+ obj->pampd_count = 0;
+#ifdef CONFIG_RAMSTER
+ if (tmem_pamops.new_obj != NULL)
+ (*tmem_pamops.new_obj)(obj);
+#endif
+ SET_SENTINEL(obj, OBJ);
+
+ if (__tmem_obj_find(hb, oidp, &parent, &new))
+ BUG();
+
+ rb_link_node(&obj->rb_tree_node, parent, new);
+ rb_insert_color(&obj->rb_tree_node, root);
+}
+
+/*
+ * Tmem is managed as a set of tmem_pools with certain attributes, such as
+ * "ephemeral" vs "persistent". These attributes apply to all tmem_objs
+ * and all pampds that belong to a tmem_pool. A tmem_pool is created
+ * or deleted relatively rarely (for example, when a filesystem is
+ * mounted or unmounted).
+ */
+
+/* flush all data from a pool and, optionally, free it */
+static void tmem_pool_flush(struct tmem_pool *pool, bool destroy)
+{
+ struct rb_node *rbnode;
+ struct tmem_obj *obj;
+ struct tmem_hashbucket *hb = &pool->hashbucket[0];
+ int i;
+
+ BUG_ON(pool == NULL);
+ for (i = 0; i < TMEM_HASH_BUCKETS; i++, hb++) {
+ spin_lock(&hb->lock);
+ rbnode = rb_first(&hb->obj_rb_root);
+ while (rbnode != NULL) {
+ obj = rb_entry(rbnode, struct tmem_obj, rb_tree_node);
+ rbnode = rb_next(rbnode);
+ tmem_pampd_destroy_all_in_obj(obj, true);
+ tmem_obj_free(obj, hb);
+ (*tmem_hostops.obj_free)(obj, pool);
+ }
+ spin_unlock(&hb->lock);
+ }
+ if (destroy)
+ list_del(&pool->pool_list);
+}
+
+/*
+ * A tmem_obj contains a radix-tree-like tree in which the intermediate
+ * nodes are called tmem_objnodes. (The kernel lib/radix-tree.c implementation
+ * is very specialized and tuned for specific uses and is not particularly
+ * suited for use from this code, though some code from the core algorithms has
+ * been reused, thus the copyright notices below). Each tmem_objnode contains
+ * a set of pointers which point to either a set of intermediate tmem_objnodes
+ * or a set of of pampds.
+ *
+ * Portions Copyright (C) 2001 Momchil Velikov
+ * Portions Copyright (C) 2001 Christoph Hellwig
+ * Portions Copyright (C) 2005 SGI, Christoph Lameter <clameter@sgi.com>
+ */
+
+struct tmem_objnode_tree_path {
+ struct tmem_objnode *objnode;
+ int offset;
+};
+
+/* objnode height_to_maxindex translation */
+static unsigned long tmem_objnode_tree_h2max[OBJNODE_TREE_MAX_PATH + 1];
+
+static void tmem_objnode_tree_init(void)
+{
+ unsigned int ht, tmp;
+
+ for (ht = 0; ht < ARRAY_SIZE(tmem_objnode_tree_h2max); ht++) {
+ tmp = ht * OBJNODE_TREE_MAP_SHIFT;
+ if (tmp >= OBJNODE_TREE_INDEX_BITS)
+ tmem_objnode_tree_h2max[ht] = ~0UL;
+ else
+ tmem_objnode_tree_h2max[ht] =
+ (~0UL >> (OBJNODE_TREE_INDEX_BITS - tmp - 1)) >> 1;
+ }
+}
+
+static struct tmem_objnode *tmem_objnode_alloc(struct tmem_obj *obj)
+{
+ struct tmem_objnode *objnode;
+
+ ASSERT_SENTINEL(obj, OBJ);
+ BUG_ON(obj->pool == NULL);
+ ASSERT_SENTINEL(obj->pool, POOL);
+ objnode = (*tmem_hostops.objnode_alloc)(obj->pool);
+ if (unlikely(objnode == NULL))
+ goto out;
+ objnode->obj = obj;
+ SET_SENTINEL(objnode, OBJNODE);
+ memset(&objnode->slots, 0, sizeof(objnode->slots));
+ objnode->slots_in_use = 0;
+ obj->objnode_count++;
+out:
+ return objnode;
+}
+
+static void tmem_objnode_free(struct tmem_objnode *objnode)
+{
+ struct tmem_pool *pool;
+ int i;
+
+ BUG_ON(objnode == NULL);
+ for (i = 0; i < OBJNODE_TREE_MAP_SIZE; i++)
+ BUG_ON(objnode->slots[i] != NULL);
+ ASSERT_SENTINEL(objnode, OBJNODE);
+ INVERT_SENTINEL(objnode, OBJNODE);
+ BUG_ON(objnode->obj == NULL);
+ ASSERT_SENTINEL(objnode->obj, OBJ);
+ pool = objnode->obj->pool;
+ BUG_ON(pool == NULL);
+ ASSERT_SENTINEL(pool, POOL);
+ objnode->obj->objnode_count--;
+ objnode->obj = NULL;
+ (*tmem_hostops.objnode_free)(objnode, pool);
+}
+
+/*
+ * Lookup index in object and return associated pampd (or NULL if not found).
+ */
+static void **__tmem_pampd_lookup_in_obj(struct tmem_obj *obj, uint32_t index)
+{
+ unsigned int height, shift;
+ struct tmem_objnode **slot = NULL;
+
+ BUG_ON(obj == NULL);
+ ASSERT_SENTINEL(obj, OBJ);
+ BUG_ON(obj->pool == NULL);
+ ASSERT_SENTINEL(obj->pool, POOL);
+
+ height = obj->objnode_tree_height;
+ if (index > tmem_objnode_tree_h2max[obj->objnode_tree_height])
+ goto out;
+ if (height == 0 && obj->objnode_tree_root) {
+ slot = &obj->objnode_tree_root;
+ goto out;
+ }
+ shift = (height-1) * OBJNODE_TREE_MAP_SHIFT;
+ slot = &obj->objnode_tree_root;
+ while (height > 0) {
+ if (*slot == NULL)
+ goto out;
+ slot = (struct tmem_objnode **)
+ ((*slot)->slots +
+ ((index >> shift) & OBJNODE_TREE_MAP_MASK));
+ shift -= OBJNODE_TREE_MAP_SHIFT;
+ height--;
+ }
+out:
+ return slot != NULL ? (void **)slot : NULL;
+}
+
+static void *tmem_pampd_lookup_in_obj(struct tmem_obj *obj, uint32_t index)
+{
+ struct tmem_objnode **slot;
+
+ slot = (struct tmem_objnode **)__tmem_pampd_lookup_in_obj(obj, index);
+ return slot != NULL ? *slot : NULL;
+}
+
+#ifdef CONFIG_RAMSTER
+static void *tmem_pampd_replace_in_obj(struct tmem_obj *obj, uint32_t index,
+ void *new_pampd, bool no_free)
+{
+ struct tmem_objnode **slot;
+ void *ret = NULL;
+
+ slot = (struct tmem_objnode **)__tmem_pampd_lookup_in_obj(obj, index);
+ if ((slot != NULL) && (*slot != NULL)) {
+ void *old_pampd = *(void **)slot;
+ *(void **)slot = new_pampd;
+ if (!no_free)
+ (*tmem_pamops.free)(old_pampd, obj->pool,
+ NULL, 0, false);
+ ret = new_pampd;
+ }
+ return ret;
+}
+#endif
+
+static int tmem_pampd_add_to_obj(struct tmem_obj *obj, uint32_t index,
+ void *pampd)
+{
+ int ret = 0;
+ struct tmem_objnode *objnode = NULL, *newnode, *slot;
+ unsigned int height, shift;
+ int offset = 0;
+
+ /* if necessary, extend the tree to be higher */
+ if (index > tmem_objnode_tree_h2max[obj->objnode_tree_height]) {
+ height = obj->objnode_tree_height + 1;
+ if (index > tmem_objnode_tree_h2max[height])
+ while (index > tmem_objnode_tree_h2max[height])
+ height++;
+ if (obj->objnode_tree_root == NULL) {
+ obj->objnode_tree_height = height;
+ goto insert;
+ }
+ do {
+ newnode = tmem_objnode_alloc(obj);
+ if (!newnode) {
+ ret = -ENOMEM;
+ goto out;
+ }
+ newnode->slots[0] = obj->objnode_tree_root;
+ newnode->slots_in_use = 1;
+ obj->objnode_tree_root = newnode;
+ obj->objnode_tree_height++;
+ } while (height > obj->objnode_tree_height);
+ }
+insert:
+ slot = obj->objnode_tree_root;
+ height = obj->objnode_tree_height;
+ shift = (height-1) * OBJNODE_TREE_MAP_SHIFT;
+ while (height > 0) {
+ if (slot == NULL) {
+ /* add a child objnode. */
+ slot = tmem_objnode_alloc(obj);
+ if (!slot) {
+ ret = -ENOMEM;
+ goto out;
+ }
+ if (objnode) {
+
+ objnode->slots[offset] = slot;
+ objnode->slots_in_use++;
+ } else
+ obj->objnode_tree_root = slot;
+ }
+ /* go down a level */
+ offset = (index >> shift) & OBJNODE_TREE_MAP_MASK;
+ objnode = slot;
+ slot = objnode->slots[offset];
+ shift -= OBJNODE_TREE_MAP_SHIFT;
+ height--;
+ }
+ BUG_ON(slot != NULL);
+ if (objnode) {
+ objnode->slots_in_use++;
+ objnode->slots[offset] = pampd;
+ } else
+ obj->objnode_tree_root = pampd;
+ obj->pampd_count++;
+out:
+ return ret;
+}
+
+static void *tmem_pampd_delete_from_obj(struct tmem_obj *obj, uint32_t index)
+{
+ struct tmem_objnode_tree_path path[OBJNODE_TREE_MAX_PATH + 1];
+ struct tmem_objnode_tree_path *pathp = path;
+ struct tmem_objnode *slot = NULL;
+ unsigned int height, shift;
+ int offset;
+
+ BUG_ON(obj == NULL);
+ ASSERT_SENTINEL(obj, OBJ);
+ BUG_ON(obj->pool == NULL);
+ ASSERT_SENTINEL(obj->pool, POOL);
+ height = obj->objnode_tree_height;
+ if (index > tmem_objnode_tree_h2max[height])
+ goto out;
+ slot = obj->objnode_tree_root;
+ if (height == 0 && obj->objnode_tree_root) {
+ obj->objnode_tree_root = NULL;
+ goto out;
+ }
+ shift = (height - 1) * OBJNODE_TREE_MAP_SHIFT;
+ pathp->objnode = NULL;
+ do {
+ if (slot == NULL)
+ goto out;
+ pathp++;
+ offset = (index >> shift) & OBJNODE_TREE_MAP_MASK;
+ pathp->offset = offset;
+ pathp->objnode = slot;
+ slot = slot->slots[offset];
+ shift -= OBJNODE_TREE_MAP_SHIFT;
+ height--;
+ } while (height > 0);
+ if (slot == NULL)
+ goto out;
+ while (pathp->objnode) {
+ pathp->objnode->slots[pathp->offset] = NULL;
+ pathp->objnode->slots_in_use--;
+ if (pathp->objnode->slots_in_use) {
+ if (pathp->objnode == obj->objnode_tree_root) {
+ while (obj->objnode_tree_height > 0 &&
+ obj->objnode_tree_root->slots_in_use == 1 &&
+ obj->objnode_tree_root->slots[0]) {
+ struct tmem_objnode *to_free =
+ obj->objnode_tree_root;
+
+ obj->objnode_tree_root =
+ to_free->slots[0];
+ obj->objnode_tree_height--;
+ to_free->slots[0] = NULL;
+ to_free->slots_in_use = 0;
+ tmem_objnode_free(to_free);
+ }
+ }
+ goto out;
+ }
+ tmem_objnode_free(pathp->objnode); /* 0 slots used, free it */
+ pathp--;
+ }
+ obj->objnode_tree_height = 0;
+ obj->objnode_tree_root = NULL;
+
+out:
+ if (slot != NULL)
+ obj->pampd_count--;
+ BUG_ON(obj->pampd_count < 0);
+ return slot;
+}
+
+/* Recursively walk the objnode_tree destroying pampds and objnodes. */
+static void tmem_objnode_node_destroy(struct tmem_obj *obj,
+ struct tmem_objnode *objnode,
+ unsigned int ht)
+{
+ int i;
+
+ if (ht == 0)
+ return;
+ for (i = 0; i < OBJNODE_TREE_MAP_SIZE; i++) {
+ if (objnode->slots[i]) {
+ if (ht == 1) {
+ obj->pampd_count--;
+ (*tmem_pamops.free)(objnode->slots[i],
+ obj->pool, NULL, 0, true);
+ objnode->slots[i] = NULL;
+ continue;
+ }
+ tmem_objnode_node_destroy(obj, objnode->slots[i], ht-1);
+ tmem_objnode_free(objnode->slots[i]);
+ objnode->slots[i] = NULL;
+ }
+ }
+}
+
+static void tmem_pampd_destroy_all_in_obj(struct tmem_obj *obj,
+ bool pool_destroy)
+{
+ if (obj->objnode_tree_root == NULL)
+ return;
+ if (obj->objnode_tree_height == 0) {
+ obj->pampd_count--;
+ (*tmem_pamops.free)(obj->objnode_tree_root,
+ obj->pool, NULL, 0, true);
+ } else {
+ tmem_objnode_node_destroy(obj, obj->objnode_tree_root,
+ obj->objnode_tree_height);
+ tmem_objnode_free(obj->objnode_tree_root);
+ obj->objnode_tree_height = 0;
+ }
+ obj->objnode_tree_root = NULL;
+#ifdef CONFIG_RAMSTER
+ if (tmem_pamops.free_obj != NULL)
+ (*tmem_pamops.free_obj)(obj->pool, obj, pool_destroy);
+#endif
+}
+
+/*
+ * Tmem is operated on by a set of well-defined actions:
+ * "put", "get", "flush", "flush_object", "new pool" and "destroy pool".
+ * (The tmem ABI allows for subpages and exchanges but these operations
+ * are not included in this implementation.)
+ *
+ * These "tmem core" operations are implemented in the following functions.
+ */
+
+/*
+ * "Put" a page, e.g. associate the passed pampd with the passed handle.
+ * Tmem_put is complicated by a corner case: What if a page with matching
+ * handle already exists in tmem? To guarantee coherency, one of two
+ * actions is necessary: Either the data for the page must be overwritten,
+ * or the page must be "flushed" so that the data is not accessible to a
+ * subsequent "get". Since these "duplicate puts" are relatively rare,
+ * this implementation always flushes for simplicity.
+ */
+int tmem_put(struct tmem_pool *pool, struct tmem_oid *oidp, uint32_t index,
+ bool raw, void *pampd_to_use)
+{
+ struct tmem_obj *obj = NULL, *objfound = NULL, *objnew = NULL;
+ void *pampd = NULL, *pampd_del = NULL;
+ int ret = -ENOMEM;
+ struct tmem_hashbucket *hb;
+
+ hb = &pool->hashbucket[tmem_oid_hash(oidp)];
+ spin_lock(&hb->lock);
+ obj = objfound = tmem_obj_find(hb, oidp);
+ if (obj != NULL) {
+ pampd = tmem_pampd_lookup_in_obj(objfound, index);
+ if (pampd != NULL) {
+ /* if found, is a dup put, flush the old one */
+ pampd_del = tmem_pampd_delete_from_obj(obj, index);
+ BUG_ON(pampd_del != pampd);
+ (*tmem_pamops.free)(pampd, pool, oidp, index, true);
+ if (obj->pampd_count == 0) {
+ objnew = obj;
+ objfound = NULL;
+ }
+ pampd = NULL;
+ }
+ } else {
+ obj = objnew = (*tmem_hostops.obj_alloc)(pool);
+ if (unlikely(obj == NULL)) {
+ ret = -ENOMEM;
+ goto out;
+ }
+ tmem_obj_init(obj, hb, pool, oidp);
+ }
+ BUG_ON(obj == NULL);
+ BUG_ON(((objnew != obj) && (objfound != obj)) || (objnew == objfound));
+ pampd = pampd_to_use;
+ BUG_ON(pampd_to_use == NULL);
+ ret = tmem_pampd_add_to_obj(obj, index, pampd);
+ if (unlikely(ret == -ENOMEM))
+ /* may have partially built objnode tree ("stump") */
+ goto delete_and_free;
+ (*tmem_pamops.create_finish)(pampd, is_ephemeral(pool));
+ goto out;
+
+delete_and_free:
+ (void)tmem_pampd_delete_from_obj(obj, index);
+ if (pampd)
+ (*tmem_pamops.free)(pampd, pool, NULL, 0, true);
+ if (objnew) {
+ tmem_obj_free(objnew, hb);
+ (*tmem_hostops.obj_free)(objnew, pool);
+ }
+out:
+ spin_unlock(&hb->lock);
+ return ret;
+}
+
+#ifdef CONFIG_RAMSTER
+/*
+ * For ramster only: The following routines provide a two-step sequence
+ * to allow the caller to replace a pampd in the tmem data structures with
+ * another pampd. Here, we lookup the passed handle and, if found, return the
+ * associated pampd and object, leaving the hashbucket locked and returning
+ * a reference to it. The caller is expected to immediately call the
+ * matching tmem_localify_finish routine which will handles the replacement
+ * and unlocks the hashbucket.
+ */
+void *tmem_localify_get_pampd(struct tmem_pool *pool, struct tmem_oid *oidp,
+ uint32_t index, struct tmem_obj **ret_obj,
+ void **saved_hb)
+{
+ struct tmem_hashbucket *hb;
+ struct tmem_obj *obj = NULL;
+ void *pampd = NULL;
+
+ hb = &pool->hashbucket[tmem_oid_hash(oidp)];
+ spin_lock(&hb->lock);
+ obj = tmem_obj_find(hb, oidp);
+ if (likely(obj != NULL))
+ pampd = tmem_pampd_lookup_in_obj(obj, index);
+ *ret_obj = obj;
+ *saved_hb = (void *)hb;
+ /* note, hashbucket remains locked */
+ return pampd;
+}
+
+void tmem_localify_finish(struct tmem_obj *obj, uint32_t index,
+ void *pampd, void *saved_hb, bool delete)
+{
+ struct tmem_hashbucket *hb = (struct tmem_hashbucket *)saved_hb;
+
+ BUG_ON(!spin_is_locked(&hb->lock));
+ if (pampd != NULL) {
+ BUG_ON(obj == NULL);
+ (void)tmem_pampd_replace_in_obj(obj, index, pampd, 1);
+ (*tmem_pamops.create_finish)(pampd, is_ephemeral(obj->pool));
+ } else if (delete) {
+ BUG_ON(obj == NULL);
+ (void)tmem_pampd_delete_from_obj(obj, index);
+ }
+ spin_unlock(&hb->lock);
+}
+
+/*
+ * For ramster only. Helper function to support asynchronous tmem_get.
+ */
+static int tmem_repatriate(void **ppampd, struct tmem_hashbucket *hb,
+ struct tmem_pool *pool, struct tmem_oid *oidp,
+ uint32_t index, bool free, char *data)
+{
+ void *old_pampd = *ppampd, *new_pampd = NULL;
+ bool intransit = false;
+ int ret = 0;
+
+ if (!is_ephemeral(pool))
+ new_pampd = (*tmem_pamops.repatriate_preload)(
+ old_pampd, pool, oidp, index, &intransit);
+ if (intransit)
+ ret = -EAGAIN;
+ else if (new_pampd != NULL)
+ *ppampd = new_pampd;
+ /* must release the hb->lock else repatriate can't sleep */
+ spin_unlock(&hb->lock);
+ if (!intransit)
+ ret = (*tmem_pamops.repatriate)(old_pampd, new_pampd, pool,
+ oidp, index, free, data);
+ if (ret == -EAGAIN) {
+ /* rare I think, but should cond_resched()??? */
+ usleep_range(10, 1000);
+ } else if (ret == -ENOTCONN || ret == -EHOSTDOWN) {
+ ret = -1;
+ } else if (ret != 0 && ret != -ENOENT) {
+ ret = -1;
+ }
+ /* note hb->lock has now been unlocked */
+ return ret;
+}
+
+/*
+ * For ramster only. If a page in tmem matches the handle, replace the
+ * page so that any subsequent "get" gets the new page. Returns 0 if
+ * there was a page to replace, else returns -1.
+ */
+int tmem_replace(struct tmem_pool *pool, struct tmem_oid *oidp,
+ uint32_t index, void *new_pampd)
+{
+ struct tmem_obj *obj;
+ int ret = -1;
+ struct tmem_hashbucket *hb;
+
+ hb = &pool->hashbucket[tmem_oid_hash(oidp)];
+ spin_lock(&hb->lock);
+ obj = tmem_obj_find(hb, oidp);
+ if (obj == NULL)
+ goto out;
+ new_pampd = tmem_pampd_replace_in_obj(obj, index, new_pampd, 0);
+ /* if we bug here, pamops wasn't properly set up for ramster */
+ BUG_ON(tmem_pamops.replace_in_obj == NULL);
+ ret = (*tmem_pamops.replace_in_obj)(new_pampd, obj);
+out:
+ spin_unlock(&hb->lock);
+ return ret;
+}
+#endif
+
+/*
+ * "Get" a page, e.g. if a pampd can be found matching the passed handle,
+ * use a pamops callback to recreated the page from the pampd with the
+ * matching handle. By tmem definition, when a "get" is successful on
+ * an ephemeral page, the page is "flushed", and when a "get" is successful
+ * on a persistent page, the page is retained in tmem. Note that to preserve
+ * coherency, "get" can never be skipped if tmem contains the data.
+ * That is, if a get is done with a certain handle and fails, any
+ * subsequent "get" must also fail (unless of course there is a
+ * "put" done with the same handle).
+ */
+int tmem_get(struct tmem_pool *pool, struct tmem_oid *oidp, uint32_t index,
+ char *data, size_t *sizep, bool raw, int get_and_free)
+{
+ struct tmem_obj *obj;
+ void *pampd = NULL;
+ bool ephemeral = is_ephemeral(pool);
+ int ret = -1;
+ struct tmem_hashbucket *hb;
+ bool free = (get_and_free == 1) || ((get_and_free == 0) && ephemeral);
+ bool lock_held = false;
+ void **ppampd;
+
+ do {
+ hb = &pool->hashbucket[tmem_oid_hash(oidp)];
+ spin_lock(&hb->lock);
+ lock_held = true;
+ obj = tmem_obj_find(hb, oidp);
+ if (obj == NULL)
+ goto out;
+ ppampd = __tmem_pampd_lookup_in_obj(obj, index);
+ if (ppampd == NULL)
+ goto out;
+#ifdef CONFIG_RAMSTER
+ if ((tmem_pamops.is_remote != NULL) &&
+ tmem_pamops.is_remote(*ppampd)) {
+ ret = tmem_repatriate(ppampd, hb, pool, oidp,
+ index, free, data);
+ /* tmem_repatriate releases hb->lock */
+ lock_held = false;
+ *sizep = PAGE_SIZE;
+ if (ret != -EAGAIN)
+ goto out;
+ }
+#endif
+ } while (ret == -EAGAIN);
+ if (free)
+ pampd = tmem_pampd_delete_from_obj(obj, index);
+ else
+ pampd = tmem_pampd_lookup_in_obj(obj, index);
+ if (pampd == NULL)
+ goto out;
+ if (free) {
+ if (obj->pampd_count == 0) {
+ tmem_obj_free(obj, hb);
+ (*tmem_hostops.obj_free)(obj, pool);
+ obj = NULL;
+ }
+ }
+ if (free)
+ ret = (*tmem_pamops.get_data_and_free)(
+ data, sizep, raw, pampd, pool, oidp, index);
+ else
+ ret = (*tmem_pamops.get_data)(
+ data, sizep, raw, pampd, pool, oidp, index);
+ if (ret < 0)
+ goto out;
+ ret = 0;
+out:
+ if (lock_held)
+ spin_unlock(&hb->lock);
+ return ret;
+}
+
+/*
+ * If a page in tmem matches the handle, "flush" this page from tmem such
+ * that any subsequent "get" does not succeed (unless, of course, there
+ * was another "put" with the same handle).
+ */
+int tmem_flush_page(struct tmem_pool *pool,
+ struct tmem_oid *oidp, uint32_t index)
+{
+ struct tmem_obj *obj;
+ void *pampd;
+ int ret = -1;
+ struct tmem_hashbucket *hb;
+
+ hb = &pool->hashbucket[tmem_oid_hash(oidp)];
+ spin_lock(&hb->lock);
+ obj = tmem_obj_find(hb, oidp);
+ if (obj == NULL)
+ goto out;
+ pampd = tmem_pampd_delete_from_obj(obj, index);
+ if (pampd == NULL)
+ goto out;
+ (*tmem_pamops.free)(pampd, pool, oidp, index, true);
+ if (obj->pampd_count == 0) {
+ tmem_obj_free(obj, hb);
+ (*tmem_hostops.obj_free)(obj, pool);
+ }
+ ret = 0;
+
+out:
+ spin_unlock(&hb->lock);
+ return ret;
+}
+
+/*
+ * "Flush" all pages in tmem matching this oid.
+ */
+int tmem_flush_object(struct tmem_pool *pool, struct tmem_oid *oidp)
+{
+ struct tmem_obj *obj;
+ struct tmem_hashbucket *hb;
+ int ret = -1;
+
+ hb = &pool->hashbucket[tmem_oid_hash(oidp)];
+ spin_lock(&hb->lock);
+ obj = tmem_obj_find(hb, oidp);
+ if (obj == NULL)
+ goto out;
+ tmem_pampd_destroy_all_in_obj(obj, false);
+ tmem_obj_free(obj, hb);
+ (*tmem_hostops.obj_free)(obj, pool);
+ ret = 0;
+
+out:
+ spin_unlock(&hb->lock);
+ return ret;
+}
+
+/*
+ * "Flush" all pages (and tmem_objs) from this tmem_pool and disable
+ * all subsequent access to this tmem_pool.
+ */
+int tmem_destroy_pool(struct tmem_pool *pool)
+{
+ int ret = -1;
+
+ if (pool == NULL)
+ goto out;
+ tmem_pool_flush(pool, 1);
+ ret = 0;
+out:
+ return ret;
+}
+
+static LIST_HEAD(tmem_global_pool_list);
+
+/*
+ * Create a new tmem_pool with the provided flag and return
+ * a pool id provided by the tmem host implementation.
+ */
+void tmem_new_pool(struct tmem_pool *pool, uint32_t flags)
+{
+ int persistent = flags & TMEM_POOL_PERSIST;
+ int shared = flags & TMEM_POOL_SHARED;
+ struct tmem_hashbucket *hb = &pool->hashbucket[0];
+ int i;
+
+ for (i = 0; i < TMEM_HASH_BUCKETS; i++, hb++) {
+ hb->obj_rb_root = RB_ROOT;
+ spin_lock_init(&hb->lock);
+ }
+ INIT_LIST_HEAD(&pool->pool_list);
+ atomic_set(&pool->obj_count, 0);
+ SET_SENTINEL(pool, POOL);
+ list_add_tail(&pool->pool_list, &tmem_global_pool_list);
+ pool->persistent = persistent;
+ pool->shared = shared;
+}
--- /dev/null
+/*
+ * tmem.h
+ *
+ * Transcendent memory
+ *
+ * Copyright (c) 2009-2012, Dan Magenheimer, Oracle Corp.
+ */
+
+#ifndef _TMEM_H_
+#define _TMEM_H_
+
+#include <linux/types.h>
+#include <linux/highmem.h>
+#include <linux/hash.h>
+#include <linux/atomic.h>
+
+/*
+ * These are defined by the Xen<->Linux ABI so should remain consistent
+ */
+#define TMEM_POOL_PERSIST 1
+#define TMEM_POOL_SHARED 2
+#define TMEM_POOL_PRECOMPRESSED 4
+#define TMEM_POOL_PAGESIZE_SHIFT 4
+#define TMEM_POOL_PAGESIZE_MASK 0xf
+#define TMEM_POOL_RESERVED_BITS 0x00ffff00
+
+/*
+ * sentinels have proven very useful for debugging but can be removed
+ * or disabled before final merge.
+ */
+#undef SENTINELS
+#ifdef SENTINELS
+#define DECL_SENTINEL uint32_t sentinel;
+#define SET_SENTINEL(_x, _y) (_x->sentinel = _y##_SENTINEL)
+#define INVERT_SENTINEL(_x, _y) (_x->sentinel = ~_y##_SENTINEL)
+#define ASSERT_SENTINEL(_x, _y) WARN_ON(_x->sentinel != _y##_SENTINEL)
+#define ASSERT_INVERTED_SENTINEL(_x, _y) WARN_ON(_x->sentinel != ~_y##_SENTINEL)
+#else
+#define DECL_SENTINEL
+#define SET_SENTINEL(_x, _y) do { } while (0)
+#define INVERT_SENTINEL(_x, _y) do { } while (0)
+#define ASSERT_SENTINEL(_x, _y) do { } while (0)
+#define ASSERT_INVERTED_SENTINEL(_x, _y) do { } while (0)
+#endif
+
+#define ASSERT_SPINLOCK(_l) lockdep_assert_held(_l)
+
+/*
+ * A pool is the highest-level data structure managed by tmem and
+ * usually corresponds to a large independent set of pages such as
+ * a filesystem. Each pool has an id, and certain attributes and counters.
+ * It also contains a set of hash buckets, each of which contains an rbtree
+ * of objects and a lock to manage concurrency within the pool.
+ */
+
+#define TMEM_HASH_BUCKET_BITS 8
+#define TMEM_HASH_BUCKETS (1<<TMEM_HASH_BUCKET_BITS)
+
+struct tmem_hashbucket {
+ struct rb_root obj_rb_root;
+ spinlock_t lock;
+};
+
+struct tmem_pool {
+ void *client; /* "up" for some clients, avoids table lookup */
+ struct list_head pool_list;
+ uint32_t pool_id;
+ bool persistent;
+ bool shared;
+ atomic_t obj_count;
+ atomic_t refcount;
+ struct tmem_hashbucket hashbucket[TMEM_HASH_BUCKETS];
+ DECL_SENTINEL
+};
+
+#define is_persistent(_p) (_p->persistent)
+#define is_ephemeral(_p) (!(_p->persistent))
+
+/*
+ * An object id ("oid") is large: 192-bits (to ensure, for example, files
+ * in a modern filesystem can be uniquely identified).
+ */
+
+struct tmem_oid {
+ uint64_t oid[3];
+};
+
+static inline void tmem_oid_set_invalid(struct tmem_oid *oidp)
+{
+ oidp->oid[0] = oidp->oid[1] = oidp->oid[2] = -1UL;
+}
+
+static inline bool tmem_oid_valid(struct tmem_oid *oidp)
+{
+ return oidp->oid[0] != -1UL || oidp->oid[1] != -1UL ||
+ oidp->oid[2] != -1UL;
+}
+
+static inline int tmem_oid_compare(struct tmem_oid *left,
+ struct tmem_oid *right)
+{
+ int ret;
+
+ if (left->oid[2] == right->oid[2]) {
+ if (left->oid[1] == right->oid[1]) {
+ if (left->oid[0] == right->oid[0])
+ ret = 0;
+ else if (left->oid[0] < right->oid[0])
+ ret = -1;
+ else
+ return 1;
+ } else if (left->oid[1] < right->oid[1])
+ ret = -1;
+ else
+ ret = 1;
+ } else if (left->oid[2] < right->oid[2])
+ ret = -1;
+ else
+ ret = 1;
+ return ret;
+}
+
+static inline unsigned tmem_oid_hash(struct tmem_oid *oidp)
+{
+ return hash_long(oidp->oid[0] ^ oidp->oid[1] ^ oidp->oid[2],
+ TMEM_HASH_BUCKET_BITS);
+}
+
+#ifdef CONFIG_RAMSTER
+struct tmem_xhandle {
+ uint8_t client_id;
+ uint8_t xh_data_cksum;
+ uint16_t xh_data_size;
+ uint16_t pool_id;
+ struct tmem_oid oid;
+ uint32_t index;
+ void *extra;
+};
+
+static inline struct tmem_xhandle tmem_xhandle_fill(uint16_t client_id,
+ struct tmem_pool *pool,
+ struct tmem_oid *oidp,
+ uint32_t index)
+{
+ struct tmem_xhandle xh;
+ xh.client_id = client_id;
+ xh.xh_data_cksum = (uint8_t)-1;
+ xh.xh_data_size = (uint16_t)-1;
+ xh.pool_id = pool->pool_id;
+ xh.oid = *oidp;
+ xh.index = index;
+ return xh;
+}
+#endif
+
+
+/*
+ * A tmem_obj contains an identifier (oid), pointers to the parent
+ * pool and the rb_tree to which it belongs, counters, and an ordered
+ * set of pampds, structured in a radix-tree-like tree. The intermediate
+ * nodes of the tree are called tmem_objnodes.
+ */
+
+struct tmem_objnode;
+
+struct tmem_obj {
+ struct tmem_oid oid;
+ struct tmem_pool *pool;
+ struct rb_node rb_tree_node;
+ struct tmem_objnode *objnode_tree_root;
+ unsigned int objnode_tree_height;
+ unsigned long objnode_count;
+ long pampd_count;
+#ifdef CONFIG_RAMSTER
+ /*
+ * for current design of ramster, all pages belonging to
+ * an object reside on the same remotenode and extra is
+ * used to record the number of the remotenode so a
+ * flush-object operation can specify it
+ */
+ void *extra; /* for private use by pampd implementation */
+#endif
+ DECL_SENTINEL
+};
+
+#define OBJNODE_TREE_MAP_SHIFT 6
+#define OBJNODE_TREE_MAP_SIZE (1UL << OBJNODE_TREE_MAP_SHIFT)
+#define OBJNODE_TREE_MAP_MASK (OBJNODE_TREE_MAP_SIZE-1)
+#define OBJNODE_TREE_INDEX_BITS (8 /* CHAR_BIT */ * sizeof(unsigned long))
+#define OBJNODE_TREE_MAX_PATH \
+ (OBJNODE_TREE_INDEX_BITS/OBJNODE_TREE_MAP_SHIFT + 2)
+
+struct tmem_objnode {
+ struct tmem_obj *obj;
+ DECL_SENTINEL
+ void *slots[OBJNODE_TREE_MAP_SIZE];
+ unsigned int slots_in_use;
+};
+
+struct tmem_handle {
+ struct tmem_oid oid; /* 24 bytes */
+ uint32_t index;
+ uint16_t pool_id;
+ uint16_t client_id;
+};
+
+
+/* pampd abstract datatype methods provided by the PAM implementation */
+struct tmem_pamops {
+ void (*create_finish)(void *, bool);
+ int (*get_data)(char *, size_t *, bool, void *, struct tmem_pool *,
+ struct tmem_oid *, uint32_t);
+ int (*get_data_and_free)(char *, size_t *, bool, void *,
+ struct tmem_pool *, struct tmem_oid *,
+ uint32_t);
+ void (*free)(void *, struct tmem_pool *,
+ struct tmem_oid *, uint32_t, bool);
+#ifdef CONFIG_RAMSTER
+ void (*new_obj)(struct tmem_obj *);
+ void (*free_obj)(struct tmem_pool *, struct tmem_obj *, bool);
+ void *(*repatriate_preload)(void *, struct tmem_pool *,
+ struct tmem_oid *, uint32_t, bool *);
+ int (*repatriate)(void *, void *, struct tmem_pool *,
+ struct tmem_oid *, uint32_t, bool, void *);
+ bool (*is_remote)(void *);
+ int (*replace_in_obj)(void *, struct tmem_obj *);
+#endif
+};
+extern void tmem_register_pamops(struct tmem_pamops *m);
+
+/* memory allocation methods provided by the host implementation */
+struct tmem_hostops {
+ struct tmem_obj *(*obj_alloc)(struct tmem_pool *);
+ void (*obj_free)(struct tmem_obj *, struct tmem_pool *);
+ struct tmem_objnode *(*objnode_alloc)(struct tmem_pool *);
+ void (*objnode_free)(struct tmem_objnode *, struct tmem_pool *);
+};
+extern void tmem_register_hostops(struct tmem_hostops *m);
+
+/* core tmem accessor functions */
+extern int tmem_put(struct tmem_pool *, struct tmem_oid *, uint32_t index,
+ bool, void *);
+extern int tmem_get(struct tmem_pool *, struct tmem_oid *, uint32_t index,
+ char *, size_t *, bool, int);
+extern int tmem_flush_page(struct tmem_pool *, struct tmem_oid *,
+ uint32_t index);
+extern int tmem_flush_object(struct tmem_pool *, struct tmem_oid *);
+extern int tmem_destroy_pool(struct tmem_pool *);
+extern void tmem_new_pool(struct tmem_pool *, uint32_t);
+#ifdef CONFIG_RAMSTER
+extern int tmem_replace(struct tmem_pool *, struct tmem_oid *, uint32_t index,
+ void *);
+extern void *tmem_localify_get_pampd(struct tmem_pool *, struct tmem_oid *,
+ uint32_t index, struct tmem_obj **,
+ void **);
+extern void tmem_localify_finish(struct tmem_obj *, uint32_t index,
+ void *, void *, bool);
+#endif
+#endif /* _TMEM_H */
--- /dev/null
+/*
+ * zbud.c - Compression buddies allocator
+ *
+ * Copyright (c) 2010-2012, Dan Magenheimer, Oracle Corp.
+ *
+ * Compression buddies ("zbud") provides for efficiently packing two
+ * (or, possibly in the future, more) compressed pages ("zpages") into
+ * a single "raw" pageframe and for tracking both zpages and pageframes
+ * so that whole pageframes can be easily reclaimed in LRU-like order.
+ * It is designed to be used in conjunction with transcendent memory
+ * ("tmem"); for example separate LRU lists are maintained for persistent
+ * vs. ephemeral pages.
+ *
+ * A zbudpage is an overlay for a struct page and thus each zbudpage
+ * refers to a physical pageframe of RAM. When the caller passes a
+ * struct page from the kernel's page allocator, zbud "transforms" it
+ * to a zbudpage which sets/uses a different set of fields than the
+ * struct-page and thus must "untransform" it back by reinitializing
+ * certain fields before the struct-page can be freed. The fields
+ * of a zbudpage include a page lock for controlling access to the
+ * corresponding pageframe, and there is a size field for each zpage.
+ * Each zbudpage also lives on two linked lists: a "budlist" which is
+ * used to support efficient buddying of zpages; and an "lru" which
+ * is used for reclaiming pageframes in approximately least-recently-used
+ * order.
+ *
+ * A zbudpageframe is a pageframe divided up into aligned 64-byte "chunks"
+ * which contain the compressed data for zero, one, or two zbuds. Contained
+ * with the compressed data is a tmem_handle which is a key to allow
+ * the same data to be found via the tmem interface so the zpage can
+ * be invalidated (for ephemeral pages) or repatriated to the swap cache
+ * (for persistent pages). The contents of a zbudpageframe must never
+ * be accessed without holding the page lock for the corresponding
+ * zbudpage and, to accomodate highmem machines, the contents may
+ * only be examined or changes when kmapped. Thus, when in use, a
+ * kmapped zbudpageframe is referred to in the zbud code as "void *zbpg".
+ *
+ * Note that the term "zbud" refers to the combination of a zpage and
+ * a tmem_handle that is stored as one of possibly two "buddied" zpages;
+ * it also generically refers to this allocator... sorry for any confusion.
+ *
+ * A zbudref is a pointer to a struct zbudpage (which can be cast to a
+ * struct page), with the LSB either cleared or set to indicate, respectively,
+ * the first or second zpage in the zbudpageframe. Since a zbudref can be
+ * cast to a pointer, it is used as the tmem "pampd" pointer and uniquely
+ * references a stored tmem page and so is the only zbud data structure
+ * externally visible to zbud.c/zbud.h.
+ *
+ * Since we wish to reclaim entire pageframes but zpages may be randomly
+ * added and deleted to any given pageframe, we approximate LRU by
+ * promoting a pageframe to MRU when a zpage is added to it, but
+ * leaving it at the current place in the list when a zpage is deleted
+ * from it. As a side effect, zpages that are difficult to buddy (e.g.
+ * very large paages) will be reclaimed faster than average, which seems
+ * reasonable.
+ *
+ * In the current implementation, no more than two zpages may be stored in
+ * any pageframe and no zpage ever crosses a pageframe boundary. While
+ * other zpage allocation mechanisms may allow greater density, this two
+ * zpage-per-pageframe limit both ensures simple reclaim of pageframes
+ * (including garbage collection of references to the contents of those
+ * pageframes from tmem data structures) AND avoids the need for compaction.
+ * With additional complexity, zbud could be modified to support storing
+ * up to three zpages per pageframe or, to handle larger average zpages,
+ * up to three zpages per pair of pageframes, but it is not clear if the
+ * additional complexity would be worth it. So consider it an exercise
+ * for future developers.
+ *
+ * Note also that zbud does no page allocation or freeing. This is so
+ * that the caller has complete control over and, for accounting, visibility
+ * into if/when pages are allocated and freed.
+ *
+ * Finally, note that zbud limits the size of zpages it can store; the
+ * caller must check the zpage size with zbud_max_buddy_size before
+ * storing it, else BUGs will result. User beware.
+ */
+
+#include <linux/module.h>
+#include <linux/highmem.h>
+#include <linux/list.h>
+#include <linux/spinlock.h>
+#include <linux/pagemap.h>
+#include <linux/atomic.h>
+#include <linux/bug.h>
+#include "tmem.h"
+#include "zcache.h"
+#include "zbud.h"
+
+/*
+ * We need to ensure that a struct zbudpage is never larger than a
+ * struct page. This is checked with a BUG_ON in zbud_init.
+ *
+ * The unevictable field indicates that a zbud is being added to the
+ * zbudpage. Since this is a two-phase process (due to tmem locking),
+ * this field locks the zbudpage against eviction when a zbud match
+ * or creation is in process. Since this addition process may occur
+ * in parallel for two zbuds in one zbudpage, the field is a counter
+ * that must not exceed two.
+ */
+struct zbudpage {
+ union {
+ struct page page;
+ struct {
+ unsigned long space_for_flags;
+ struct {
+ unsigned zbud0_size:12;
+ unsigned zbud1_size:12;
+ unsigned unevictable:2;
+ };
+ struct list_head budlist;
+ struct list_head lru;
+ };
+ };
+};
+
+struct zbudref {
+ union {
+ struct zbudpage *zbudpage;
+ unsigned long zbudref;
+ };
+};
+
+#define CHUNK_SHIFT 6
+#define CHUNK_SIZE (1 << CHUNK_SHIFT)
+#define CHUNK_MASK (~(CHUNK_SIZE-1))
+#define NCHUNKS (PAGE_SIZE >> CHUNK_SHIFT)
+#define MAX_CHUNK (NCHUNKS-1)
+
+/*
+ * The following functions deal with the difference between struct
+ * page and struct zbudpage. Note the hack of using the pageflags
+ * from struct page; this is to avoid duplicating all the complex
+ * pageflag macros.
+ */
+static inline void zbudpage_spin_lock(struct zbudpage *zbudpage)
+{
+ struct page *page = (struct page *)zbudpage;
+
+ while (unlikely(test_and_set_bit_lock(PG_locked, &page->flags))) {
+ do {
+ cpu_relax();
+ } while (test_bit(PG_locked, &page->flags));
+ }
+}
+
+static inline void zbudpage_spin_unlock(struct zbudpage *zbudpage)
+{
+ struct page *page = (struct page *)zbudpage;
+
+ clear_bit(PG_locked, &page->flags);
+}
+
+static inline int zbudpage_spin_trylock(struct zbudpage *zbudpage)
+{
+ return trylock_page((struct page *)zbudpage);
+}
+
+static inline int zbudpage_is_locked(struct zbudpage *zbudpage)
+{
+ return PageLocked((struct page *)zbudpage);
+}
+
+static inline void *kmap_zbudpage_atomic(struct zbudpage *zbudpage)
+{
+ return kmap_atomic((struct page *)zbudpage);
+}
+
+/*
+ * A dying zbudpage is an ephemeral page in the process of being evicted.
+ * Any data contained in the zbudpage is invalid and we are just waiting for
+ * the tmem pampds to be invalidated before freeing the page
+ */
+static inline int zbudpage_is_dying(struct zbudpage *zbudpage)
+{
+ struct page *page = (struct page *)zbudpage;
+
+ return test_bit(PG_reclaim, &page->flags);
+}
+
+static inline void zbudpage_set_dying(struct zbudpage *zbudpage)
+{
+ struct page *page = (struct page *)zbudpage;
+
+ set_bit(PG_reclaim, &page->flags);
+}
+
+static inline void zbudpage_clear_dying(struct zbudpage *zbudpage)
+{
+ struct page *page = (struct page *)zbudpage;
+
+ clear_bit(PG_reclaim, &page->flags);
+}
+
+/*
+ * A zombie zbudpage is a persistent page in the process of being evicted.
+ * The data contained in the zbudpage is valid and we are just waiting for
+ * the tmem pampds to be invalidated before freeing the page
+ */
+static inline int zbudpage_is_zombie(struct zbudpage *zbudpage)
+{
+ struct page *page = (struct page *)zbudpage;
+
+ return test_bit(PG_dirty, &page->flags);
+}
+
+static inline void zbudpage_set_zombie(struct zbudpage *zbudpage)
+{
+ struct page *page = (struct page *)zbudpage;
+
+ set_bit(PG_dirty, &page->flags);
+}
+
+static inline void zbudpage_clear_zombie(struct zbudpage *zbudpage)
+{
+ struct page *page = (struct page *)zbudpage;
+
+ clear_bit(PG_dirty, &page->flags);
+}
+
+static inline void kunmap_zbudpage_atomic(void *zbpg)
+{
+ kunmap_atomic(zbpg);
+}
+
+/*
+ * zbud "translation" and helper functions
+ */
+
+static inline struct zbudpage *zbudref_to_zbudpage(struct zbudref *zref)
+{
+ unsigned long zbud = (unsigned long)zref;
+ zbud &= ~1UL;
+ return (struct zbudpage *)zbud;
+}
+
+static inline struct zbudref *zbudpage_to_zbudref(struct zbudpage *zbudpage,
+ unsigned budnum)
+{
+ unsigned long zbud = (unsigned long)zbudpage;
+ BUG_ON(budnum > 1);
+ zbud |= budnum;
+ return (struct zbudref *)zbud;
+}
+
+static inline int zbudref_budnum(struct zbudref *zbudref)
+{
+ unsigned long zbud = (unsigned long)zbudref;
+ return zbud & 1UL;
+}
+
+static inline unsigned zbud_max_size(void)
+{
+ return MAX_CHUNK << CHUNK_SHIFT;
+}
+
+static inline unsigned zbud_size_to_chunks(unsigned size)
+{
+ BUG_ON(size == 0 || size > zbud_max_size());
+ return (size + CHUNK_SIZE - 1) >> CHUNK_SHIFT;
+}
+
+/* can only be used between kmap_zbudpage_atomic/kunmap_zbudpage_atomic! */
+static inline char *zbud_data(void *zbpg,
+ unsigned budnum, unsigned size)
+{
+ char *p;
+
+ BUG_ON(size == 0 || size > zbud_max_size());
+ p = (char *)zbpg;
+ if (budnum == 1)
+ p += PAGE_SIZE - ((size + CHUNK_SIZE - 1) & CHUNK_MASK);
+ return p;
+}
+
+/*
+ * These are all informative and exposed through debugfs... except for
+ * the arrays... anyone know how to do that? To avoid confusion for
+ * debugfs viewers, some of these should also be atomic_long_t, but
+ * I don't know how to expose atomics via debugfs either...
+ */
+static unsigned long zbud_eph_pageframes;
+static unsigned long zbud_pers_pageframes;
+static unsigned long zbud_eph_zpages;
+static unsigned long zbud_pers_zpages;
+static u64 zbud_eph_zbytes;
+static u64 zbud_pers_zbytes;
+static unsigned long zbud_eph_evicted_pageframes;
+static unsigned long zbud_pers_evicted_pageframes;
+static unsigned long zbud_eph_cumul_zpages;
+static unsigned long zbud_pers_cumul_zpages;
+static u64 zbud_eph_cumul_zbytes;
+static u64 zbud_pers_cumul_zbytes;
+static unsigned long zbud_eph_cumul_chunk_counts[NCHUNKS];
+static unsigned long zbud_pers_cumul_chunk_counts[NCHUNKS];
+static unsigned long zbud_eph_buddied_count;
+static unsigned long zbud_pers_buddied_count;
+static unsigned long zbud_eph_unbuddied_count;
+static unsigned long zbud_pers_unbuddied_count;
+static unsigned long zbud_eph_zombie_count;
+static unsigned long zbud_pers_zombie_count;
+static atomic_t zbud_eph_zombie_atomic;
+static atomic_t zbud_pers_zombie_atomic;
+
+#ifdef CONFIG_DEBUG_FS
+#include <linux/debugfs.h>
+#define zdfs debugfs_create_size_t
+#define zdfs64 debugfs_create_u64
+static int zbud_debugfs_init(void)
+{
+ struct dentry *root = debugfs_create_dir("zbud", NULL);
+ if (root == NULL)
+ return -ENXIO;
+
+ /*
+ * would be nice to dump the sizes of the unbuddied
+ * arrays, like was done with sysfs, but it doesn't
+ * look like debugfs is flexible enough to do that
+ */
+ zdfs64("eph_zbytes", S_IRUGO, root, &zbud_eph_zbytes);
+ zdfs64("eph_cumul_zbytes", S_IRUGO, root, &zbud_eph_cumul_zbytes);
+ zdfs64("pers_zbytes", S_IRUGO, root, &zbud_pers_zbytes);
+ zdfs64("pers_cumul_zbytes", S_IRUGO, root, &zbud_pers_cumul_zbytes);
+ zdfs("eph_cumul_zpages", S_IRUGO, root, &zbud_eph_cumul_zpages);
+ zdfs("eph_evicted_pageframes", S_IRUGO, root,
+ &zbud_eph_evicted_pageframes);
+ zdfs("eph_zpages", S_IRUGO, root, &zbud_eph_zpages);
+ zdfs("eph_pageframes", S_IRUGO, root, &zbud_eph_pageframes);
+ zdfs("eph_buddied_count", S_IRUGO, root, &zbud_eph_buddied_count);
+ zdfs("eph_unbuddied_count", S_IRUGO, root, &zbud_eph_unbuddied_count);
+ zdfs("pers_cumul_zpages", S_IRUGO, root, &zbud_pers_cumul_zpages);
+ zdfs("pers_evicted_pageframes", S_IRUGO, root,
+ &zbud_pers_evicted_pageframes);
+ zdfs("pers_zpages", S_IRUGO, root, &zbud_pers_zpages);
+ zdfs("pers_pageframes", S_IRUGO, root, &zbud_pers_pageframes);
+ zdfs("pers_buddied_count", S_IRUGO, root, &zbud_pers_buddied_count);
+ zdfs("pers_unbuddied_count", S_IRUGO, root, &zbud_pers_unbuddied_count);
+ zdfs("pers_zombie_count", S_IRUGO, root, &zbud_pers_zombie_count);
+ return 0;
+}
+#undef zdfs
+#undef zdfs64
+#endif
+
+/* protects the buddied list and all unbuddied lists */
+static DEFINE_SPINLOCK(zbud_eph_lists_lock);
+static DEFINE_SPINLOCK(zbud_pers_lists_lock);
+
+struct zbud_unbuddied {
+ struct list_head list;
+ unsigned count;
+};
+
+/* list N contains pages with N chunks USED and NCHUNKS-N unused */
+/* element 0 is never used but optimizing that isn't worth it */
+static struct zbud_unbuddied zbud_eph_unbuddied[NCHUNKS];
+static struct zbud_unbuddied zbud_pers_unbuddied[NCHUNKS];
+static LIST_HEAD(zbud_eph_lru_list);
+static LIST_HEAD(zbud_pers_lru_list);
+static LIST_HEAD(zbud_eph_buddied_list);
+static LIST_HEAD(zbud_pers_buddied_list);
+static LIST_HEAD(zbud_eph_zombie_list);
+static LIST_HEAD(zbud_pers_zombie_list);
+
+/*
+ * Given a struct page, transform it to a zbudpage so that it can be
+ * used by zbud and initialize fields as necessary.
+ */
+static inline struct zbudpage *zbud_init_zbudpage(struct page *page, bool eph)
+{
+ struct zbudpage *zbudpage = (struct zbudpage *)page;
+
+ BUG_ON(page == NULL);
+ INIT_LIST_HEAD(&zbudpage->budlist);
+ INIT_LIST_HEAD(&zbudpage->lru);
+ zbudpage->zbud0_size = 0;
+ zbudpage->zbud1_size = 0;
+ zbudpage->unevictable = 0;
+ if (eph)
+ zbud_eph_pageframes++;
+ else
+ zbud_pers_pageframes++;
+ return zbudpage;
+}
+
+/* "Transform" a zbudpage back to a struct page suitable to free. */
+static inline struct page *zbud_unuse_zbudpage(struct zbudpage *zbudpage,
+ bool eph)
+{
+ struct page *page = (struct page *)zbudpage;
+
+ BUG_ON(!list_empty(&zbudpage->budlist));
+ BUG_ON(!list_empty(&zbudpage->lru));
+ BUG_ON(zbudpage->zbud0_size != 0);
+ BUG_ON(zbudpage->zbud1_size != 0);
+ BUG_ON(!PageLocked(page));
+ BUG_ON(zbudpage->unevictable != 0);
+ BUG_ON(zbudpage_is_dying(zbudpage));
+ BUG_ON(zbudpage_is_zombie(zbudpage));
+ if (eph)
+ zbud_eph_pageframes--;
+ else
+ zbud_pers_pageframes--;
+ zbudpage_spin_unlock(zbudpage);
+ reset_page_mapcount(page);
+ init_page_count(page);
+ page->index = 0;
+ return page;
+}
+
+/* Mark a zbud as unused and do accounting */
+static inline void zbud_unuse_zbud(struct zbudpage *zbudpage,
+ int budnum, bool eph)
+{
+ unsigned size;
+
+ BUG_ON(!zbudpage_is_locked(zbudpage));
+ if (budnum == 0) {
+ size = zbudpage->zbud0_size;
+ zbudpage->zbud0_size = 0;
+ } else {
+ size = zbudpage->zbud1_size;
+ zbudpage->zbud1_size = 0;
+ }
+ if (eph) {
+ zbud_eph_zbytes -= size;
+ zbud_eph_zpages--;
+ } else {
+ zbud_pers_zbytes -= size;
+ zbud_pers_zpages--;
+ }
+}
+
+/*
+ * Given a zbudpage/budnum/size, a tmem handle, and a kmapped pointer
+ * to some data, set up the zbud appropriately including data copying
+ * and accounting. Note that if cdata is NULL, the data copying is
+ * skipped. (This is useful for lazy writes such as for RAMster.)
+ */
+static void zbud_init_zbud(struct zbudpage *zbudpage, struct tmem_handle *th,
+ bool eph, void *cdata,
+ unsigned budnum, unsigned size)
+{
+ char *to;
+ void *zbpg;
+ struct tmem_handle *to_th;
+ unsigned nchunks = zbud_size_to_chunks(size);
+
+ BUG_ON(!zbudpage_is_locked(zbudpage));
+ zbpg = kmap_zbudpage_atomic(zbudpage);
+ to = zbud_data(zbpg, budnum, size);
+ to_th = (struct tmem_handle *)to;
+ to_th->index = th->index;
+ to_th->oid = th->oid;
+ to_th->pool_id = th->pool_id;
+ to_th->client_id = th->client_id;
+ to += sizeof(struct tmem_handle);
+ if (cdata != NULL)
+ memcpy(to, cdata, size - sizeof(struct tmem_handle));
+ kunmap_zbudpage_atomic(zbpg);
+ if (budnum == 0)
+ zbudpage->zbud0_size = size;
+ else
+ zbudpage->zbud1_size = size;
+ if (eph) {
+ zbud_eph_cumul_chunk_counts[nchunks]++;
+ zbud_eph_zpages++;
+ zbud_eph_cumul_zpages++;
+ zbud_eph_zbytes += size;
+ zbud_eph_cumul_zbytes += size;
+ } else {
+ zbud_pers_cumul_chunk_counts[nchunks]++;
+ zbud_pers_zpages++;
+ zbud_pers_cumul_zpages++;
+ zbud_pers_zbytes += size;
+ zbud_pers_cumul_zbytes += size;
+ }
+}
+
+/*
+ * Given a locked dying zbudpage, read out the tmem handles from the data,
+ * unlock the page, then use the handles to tell tmem to flush out its
+ * references
+ */
+static void zbud_evict_tmem(struct zbudpage *zbudpage)
+{
+ int i, j;
+ uint32_t pool_id[2], client_id[2];
+ uint32_t index[2];
+ struct tmem_oid oid[2];
+ struct tmem_pool *pool;
+ void *zbpg;
+ struct tmem_handle *th;
+ unsigned size;
+
+ /* read out the tmem handles from the data and set aside */
+ zbpg = kmap_zbudpage_atomic(zbudpage);
+ for (i = 0, j = 0; i < 2; i++) {
+ size = (i == 0) ? zbudpage->zbud0_size : zbudpage->zbud1_size;
+ if (size) {
+ th = (struct tmem_handle *)zbud_data(zbpg, i, size);
+ client_id[j] = th->client_id;
+ pool_id[j] = th->pool_id;
+ oid[j] = th->oid;
+ index[j] = th->index;
+ j++;
+ zbud_unuse_zbud(zbudpage, i, true);
+ }
+ }
+ kunmap_zbudpage_atomic(zbpg);
+ zbudpage_spin_unlock(zbudpage);
+ /* zbudpage is now an unlocked dying... tell tmem to flush pointers */
+ for (i = 0; i < j; i++) {
+ pool = zcache_get_pool_by_id(client_id[i], pool_id[i]);
+ if (pool != NULL) {
+ tmem_flush_page(pool, &oid[i], index[i]);
+ zcache_put_pool(pool);
+ }
+ }
+}
+
+/*
+ * Externally callable zbud handling routines.
+ */
+
+/*
+ * Return the maximum size compressed page that can be stored (secretly
+ * setting aside space for the tmem handle.
+ */
+unsigned int zbud_max_buddy_size(void)
+{
+ return zbud_max_size() - sizeof(struct tmem_handle);
+}
+
+/*
+ * Given a zbud reference, free the corresponding zbud from all lists,
+ * mark it as unused, do accounting, and if the freeing of the zbud
+ * frees up an entire pageframe, return it to the caller (else NULL).
+ */
+struct page *zbud_free_and_delist(struct zbudref *zref, bool eph,
+ unsigned int *zsize, unsigned int *zpages)
+{
+ unsigned long budnum = zbudref_budnum(zref);
+ struct zbudpage *zbudpage = zbudref_to_zbudpage(zref);
+ struct page *page = NULL;
+ unsigned chunks, bud_size, other_bud_size;
+ spinlock_t *lists_lock =
+ eph ? &zbud_eph_lists_lock : &zbud_pers_lists_lock;
+ struct zbud_unbuddied *unbud =
+ eph ? zbud_eph_unbuddied : zbud_pers_unbuddied;
+
+
+ spin_lock(lists_lock);
+ zbudpage_spin_lock(zbudpage);
+ if (zbudpage_is_dying(zbudpage)) {
+ /* ignore dying zbudpage... see zbud_evict_pageframe_lru() */
+ zbudpage_spin_unlock(zbudpage);
+ spin_unlock(lists_lock);
+ *zpages = 0;
+ *zsize = 0;
+ goto out;
+ }
+ if (budnum == 0) {
+ bud_size = zbudpage->zbud0_size;
+ other_bud_size = zbudpage->zbud1_size;
+ } else {
+ bud_size = zbudpage->zbud1_size;
+ other_bud_size = zbudpage->zbud0_size;
+ }
+ *zsize = bud_size - sizeof(struct tmem_handle);
+ *zpages = 1;
+ zbud_unuse_zbud(zbudpage, budnum, eph);
+ if (other_bud_size == 0) { /* was unbuddied: unlist and free */
+ chunks = zbud_size_to_chunks(bud_size) ;
+ if (zbudpage_is_zombie(zbudpage)) {
+ if (eph)
+ zbud_pers_zombie_count =
+ atomic_dec_return(&zbud_eph_zombie_atomic);
+ else
+ zbud_pers_zombie_count =
+ atomic_dec_return(&zbud_pers_zombie_atomic);
+ zbudpage_clear_zombie(zbudpage);
+ } else {
+ BUG_ON(list_empty(&unbud[chunks].list));
+ list_del_init(&zbudpage->budlist);
+ unbud[chunks].count--;
+ }
+ list_del_init(&zbudpage->lru);
+ spin_unlock(lists_lock);
+ if (eph)
+ zbud_eph_unbuddied_count--;
+ else
+ zbud_pers_unbuddied_count--;
+ page = zbud_unuse_zbudpage(zbudpage, eph);
+ } else { /* was buddied: move remaining buddy to unbuddied list */
+ chunks = zbud_size_to_chunks(other_bud_size) ;
+ if (!zbudpage_is_zombie(zbudpage)) {
+ list_del_init(&zbudpage->budlist);
+ list_add_tail(&zbudpage->budlist, &unbud[chunks].list);
+ unbud[chunks].count++;
+ }
+ if (eph) {
+ zbud_eph_buddied_count--;
+ zbud_eph_unbuddied_count++;
+ } else {
+ zbud_pers_unbuddied_count++;
+ zbud_pers_buddied_count--;
+ }
+ /* don't mess with lru, no need to move it */
+ zbudpage_spin_unlock(zbudpage);
+ spin_unlock(lists_lock);
+ }
+out:
+ return page;
+}
+
+/*
+ * Given a tmem handle, and a kmapped pointer to compressed data of
+ * the given size, try to find an unbuddied zbudpage in which to
+ * create a zbud. If found, put it there, mark the zbudpage unevictable,
+ * and return a zbudref to it. Else return NULL.
+ */
+struct zbudref *zbud_match_prep(struct tmem_handle *th, bool eph,
+ void *cdata, unsigned size)
+{
+ struct zbudpage *zbudpage = NULL, *zbudpage2;
+ unsigned long budnum = 0UL;
+ unsigned nchunks;
+ int i, found_good_buddy = 0;
+ spinlock_t *lists_lock =
+ eph ? &zbud_eph_lists_lock : &zbud_pers_lists_lock;
+ struct zbud_unbuddied *unbud =
+ eph ? zbud_eph_unbuddied : zbud_pers_unbuddied;
+
+ size += sizeof(struct tmem_handle);
+ nchunks = zbud_size_to_chunks(size);
+ for (i = MAX_CHUNK - nchunks + 1; i > 0; i--) {
+ spin_lock(lists_lock);
+ if (!list_empty(&unbud[i].list)) {
+ list_for_each_entry_safe(zbudpage, zbudpage2,
+ &unbud[i].list, budlist) {
+ if (zbudpage_spin_trylock(zbudpage)) {
+ found_good_buddy = i;
+ goto found_unbuddied;
+ }
+ }
+ }
+ spin_unlock(lists_lock);
+ }
+ zbudpage = NULL;
+ goto out;
+
+found_unbuddied:
+ BUG_ON(!zbudpage_is_locked(zbudpage));
+ BUG_ON(!((zbudpage->zbud0_size == 0) ^ (zbudpage->zbud1_size == 0)));
+ if (zbudpage->zbud0_size == 0)
+ budnum = 0UL;
+ else if (zbudpage->zbud1_size == 0)
+ budnum = 1UL;
+ list_del_init(&zbudpage->budlist);
+ if (eph) {
+ list_add_tail(&zbudpage->budlist, &zbud_eph_buddied_list);
+ unbud[found_good_buddy].count--;
+ zbud_eph_unbuddied_count--;
+ zbud_eph_buddied_count++;
+ /* "promote" raw zbudpage to most-recently-used */
+ list_del_init(&zbudpage->lru);
+ list_add_tail(&zbudpage->lru, &zbud_eph_lru_list);
+ } else {
+ list_add_tail(&zbudpage->budlist, &zbud_pers_buddied_list);
+ unbud[found_good_buddy].count--;
+ zbud_pers_unbuddied_count--;
+ zbud_pers_buddied_count++;
+ /* "promote" raw zbudpage to most-recently-used */
+ list_del_init(&zbudpage->lru);
+ list_add_tail(&zbudpage->lru, &zbud_pers_lru_list);
+ }
+ zbud_init_zbud(zbudpage, th, eph, cdata, budnum, size);
+ zbudpage->unevictable++;
+ BUG_ON(zbudpage->unevictable == 3);
+ zbudpage_spin_unlock(zbudpage);
+ spin_unlock(lists_lock);
+out:
+ return zbudpage_to_zbudref(zbudpage, budnum);
+
+}
+
+/*
+ * Given a tmem handle, and a kmapped pointer to compressed data of
+ * the given size, and a newly allocated struct page, create an unevictable
+ * zbud in that new page and return a zbudref to it.
+ */
+struct zbudref *zbud_create_prep(struct tmem_handle *th, bool eph,
+ void *cdata, unsigned size,
+ struct page *newpage)
+{
+ struct zbudpage *zbudpage;
+ unsigned long budnum = 0;
+ unsigned nchunks;
+ spinlock_t *lists_lock =
+ eph ? &zbud_eph_lists_lock : &zbud_pers_lists_lock;
+ struct zbud_unbuddied *unbud =
+ eph ? zbud_eph_unbuddied : zbud_pers_unbuddied;
+
+#if 0
+ /* this may be worth it later to support decompress-in-place? */
+ static unsigned long counter;
+ budnum = counter++ & 1; /* alternate using zbud0 and zbud1 */
+#endif
+
+ if (size > zbud_max_buddy_size())
+ return NULL;
+ if (newpage == NULL)
+ return NULL;
+
+ size += sizeof(struct tmem_handle);
+ nchunks = zbud_size_to_chunks(size) ;
+ spin_lock(lists_lock);
+ zbudpage = zbud_init_zbudpage(newpage, eph);
+ zbudpage_spin_lock(zbudpage);
+ list_add_tail(&zbudpage->budlist, &unbud[nchunks].list);
+ if (eph) {
+ list_add_tail(&zbudpage->lru, &zbud_eph_lru_list);
+ zbud_eph_unbuddied_count++;
+ } else {
+ list_add_tail(&zbudpage->lru, &zbud_pers_lru_list);
+ zbud_pers_unbuddied_count++;
+ }
+ unbud[nchunks].count++;
+ zbud_init_zbud(zbudpage, th, eph, cdata, budnum, size);
+ zbudpage->unevictable++;
+ BUG_ON(zbudpage->unevictable == 3);
+ zbudpage_spin_unlock(zbudpage);
+ spin_unlock(lists_lock);
+ return zbudpage_to_zbudref(zbudpage, budnum);
+}
+
+/*
+ * Finish creation of a zbud by, assuming another zbud isn't being created
+ * in parallel, marking it evictable.
+ */
+void zbud_create_finish(struct zbudref *zref, bool eph)
+{
+ struct zbudpage *zbudpage = zbudref_to_zbudpage(zref);
+ spinlock_t *lists_lock =
+ eph ? &zbud_eph_lists_lock : &zbud_pers_lists_lock;
+
+ spin_lock(lists_lock);
+ zbudpage_spin_lock(zbudpage);
+ BUG_ON(zbudpage_is_dying(zbudpage));
+ zbudpage->unevictable--;
+ BUG_ON((int)zbudpage->unevictable < 0);
+ zbudpage_spin_unlock(zbudpage);
+ spin_unlock(lists_lock);
+}
+
+/*
+ * Given a zbudref and a struct page, decompress the data from
+ * the zbud into the physical page represented by the struct page
+ * by upcalling to zcache_decompress
+ */
+int zbud_decompress(struct page *data_page, struct zbudref *zref, bool eph,
+ void (*decompress)(char *, unsigned int, char *))
+{
+ struct zbudpage *zbudpage = zbudref_to_zbudpage(zref);
+ unsigned long budnum = zbudref_budnum(zref);
+ void *zbpg;
+ char *to_va, *from_va;
+ unsigned size;
+ int ret = -1;
+ spinlock_t *lists_lock =
+ eph ? &zbud_eph_lists_lock : &zbud_pers_lists_lock;
+
+ spin_lock(lists_lock);
+ zbudpage_spin_lock(zbudpage);
+ if (zbudpage_is_dying(zbudpage)) {
+ /* ignore dying zbudpage... see zbud_evict_pageframe_lru() */
+ goto out;
+ }
+ zbpg = kmap_zbudpage_atomic(zbudpage);
+ to_va = kmap_atomic(data_page);
+ if (budnum == 0)
+ size = zbudpage->zbud0_size;
+ else
+ size = zbudpage->zbud1_size;
+ BUG_ON(size == 0 || size > zbud_max_size());
+ from_va = zbud_data(zbpg, budnum, size);
+ from_va += sizeof(struct tmem_handle);
+ size -= sizeof(struct tmem_handle);
+ decompress(from_va, size, to_va);
+ kunmap_atomic(to_va);
+ kunmap_zbudpage_atomic(zbpg);
+ ret = 0;
+out:
+ zbudpage_spin_unlock(zbudpage);
+ spin_unlock(lists_lock);
+ return ret;
+}
+
+/*
+ * Given a zbudref and a kernel pointer, copy the data from
+ * the zbud to the kernel pointer.
+ */
+int zbud_copy_from_zbud(char *to_va, struct zbudref *zref,
+ size_t *sizep, bool eph)
+{
+ struct zbudpage *zbudpage = zbudref_to_zbudpage(zref);
+ unsigned long budnum = zbudref_budnum(zref);
+ void *zbpg;
+ char *from_va;
+ unsigned size;
+ int ret = -1;
+ spinlock_t *lists_lock =
+ eph ? &zbud_eph_lists_lock : &zbud_pers_lists_lock;
+
+ spin_lock(lists_lock);
+ zbudpage_spin_lock(zbudpage);
+ if (zbudpage_is_dying(zbudpage)) {
+ /* ignore dying zbudpage... see zbud_evict_pageframe_lru() */
+ goto out;
+ }
+ zbpg = kmap_zbudpage_atomic(zbudpage);
+ if (budnum == 0)
+ size = zbudpage->zbud0_size;
+ else
+ size = zbudpage->zbud1_size;
+ BUG_ON(size == 0 || size > zbud_max_size());
+ from_va = zbud_data(zbpg, budnum, size);
+ from_va += sizeof(struct tmem_handle);
+ size -= sizeof(struct tmem_handle);
+ *sizep = size;
+ memcpy(to_va, from_va, size);
+
+ kunmap_zbudpage_atomic(zbpg);
+ ret = 0;
+out:
+ zbudpage_spin_unlock(zbudpage);
+ spin_unlock(lists_lock);
+ return ret;
+}
+
+/*
+ * Given a zbudref and a kernel pointer, copy the data from
+ * the kernel pointer to the zbud.
+ */
+int zbud_copy_to_zbud(struct zbudref *zref, char *from_va, bool eph)
+{
+ struct zbudpage *zbudpage = zbudref_to_zbudpage(zref);
+ unsigned long budnum = zbudref_budnum(zref);
+ void *zbpg;
+ char *to_va;
+ unsigned size;
+ int ret = -1;
+ spinlock_t *lists_lock =
+ eph ? &zbud_eph_lists_lock : &zbud_pers_lists_lock;
+
+ spin_lock(lists_lock);
+ zbudpage_spin_lock(zbudpage);
+ if (zbudpage_is_dying(zbudpage)) {
+ /* ignore dying zbudpage... see zbud_evict_pageframe_lru() */
+ goto out;
+ }
+ zbpg = kmap_zbudpage_atomic(zbudpage);
+ if (budnum == 0)
+ size = zbudpage->zbud0_size;
+ else
+ size = zbudpage->zbud1_size;
+ BUG_ON(size == 0 || size > zbud_max_size());
+ to_va = zbud_data(zbpg, budnum, size);
+ to_va += sizeof(struct tmem_handle);
+ size -= sizeof(struct tmem_handle);
+ memcpy(to_va, from_va, size);
+
+ kunmap_zbudpage_atomic(zbpg);
+ ret = 0;
+out:
+ zbudpage_spin_unlock(zbudpage);
+ spin_unlock(lists_lock);
+ return ret;
+}
+
+/*
+ * Choose an ephemeral LRU zbudpage that is evictable (not locked), ensure
+ * there are no references to it remaining, and return the now unused
+ * (and re-init'ed) struct page and the total amount of compressed
+ * data that was evicted.
+ */
+struct page *zbud_evict_pageframe_lru(unsigned int *zsize, unsigned int *zpages)
+{
+ struct zbudpage *zbudpage = NULL, *zbudpage2;
+ struct zbud_unbuddied *unbud = zbud_eph_unbuddied;
+ struct page *page = NULL;
+ bool irqs_disabled = irqs_disabled();
+
+ /*
+ * Since this can be called indirectly from cleancache_put, which
+ * has interrupts disabled, as well as frontswap_put, which does not,
+ * we need to be able to handle both cases, even though it is ugly.
+ */
+ if (irqs_disabled)
+ spin_lock(&zbud_eph_lists_lock);
+ else
+ spin_lock_bh(&zbud_eph_lists_lock);
+ *zsize = 0;
+ if (list_empty(&zbud_eph_lru_list))
+ goto unlock_out;
+ list_for_each_entry_safe(zbudpage, zbudpage2, &zbud_eph_lru_list, lru) {
+ /* skip a locked zbudpage */
+ if (unlikely(!zbudpage_spin_trylock(zbudpage)))
+ continue;
+ /* skip an unevictable zbudpage */
+ if (unlikely(zbudpage->unevictable != 0)) {
+ zbudpage_spin_unlock(zbudpage);
+ continue;
+ }
+ /* got a locked evictable page */
+ goto evict_page;
+
+ }
+unlock_out:
+ /* no unlocked evictable pages, give up */
+ if (irqs_disabled)
+ spin_unlock(&zbud_eph_lists_lock);
+ else
+ spin_unlock_bh(&zbud_eph_lists_lock);
+ goto out;
+
+evict_page:
+ list_del_init(&zbudpage->budlist);
+ list_del_init(&zbudpage->lru);
+ zbudpage_set_dying(zbudpage);
+ /*
+ * the zbudpage is now "dying" and attempts to read, write,
+ * or delete data from it will be ignored
+ */
+ if (zbudpage->zbud0_size != 0 && zbudpage->zbud1_size != 0) {
+ *zsize = zbudpage->zbud0_size + zbudpage->zbud1_size -
+ (2 * sizeof(struct tmem_handle));
+ *zpages = 2;
+ } else if (zbudpage->zbud0_size != 0) {
+ unbud[zbud_size_to_chunks(zbudpage->zbud0_size)].count--;
+ *zsize = zbudpage->zbud0_size - sizeof(struct tmem_handle);
+ *zpages = 1;
+ } else if (zbudpage->zbud1_size != 0) {
+ unbud[zbud_size_to_chunks(zbudpage->zbud1_size)].count--;
+ *zsize = zbudpage->zbud1_size - sizeof(struct tmem_handle);
+ *zpages = 1;
+ } else {
+ BUG();
+ }
+ spin_unlock(&zbud_eph_lists_lock);
+ zbud_eph_evicted_pageframes++;
+ if (*zpages == 1)
+ zbud_eph_unbuddied_count--;
+ else
+ zbud_eph_buddied_count--;
+ zbud_evict_tmem(zbudpage);
+ zbudpage_spin_lock(zbudpage);
+ zbudpage_clear_dying(zbudpage);
+ page = zbud_unuse_zbudpage(zbudpage, true);
+ if (!irqs_disabled)
+ local_bh_enable();
+out:
+ return page;
+}
+
+/*
+ * Choose a persistent LRU zbudpage that is evictable (not locked), zombify it,
+ * read the tmem_handle(s) out of it into the passed array, and return the
+ * number of zbuds. Caller must perform necessary tmem functions and,
+ * indirectly, zbud functions to fetch any valid data and cause the
+ * now-zombified zbudpage to eventually be freed. We track the zombified
+ * zbudpage count so it is possible to observe if there is a leak.
+ FIXME: describe (ramster) case where data pointers are passed in for memcpy
+ */
+unsigned int zbud_make_zombie_lru(struct tmem_handle *th, unsigned char **data,
+ unsigned int *zsize, bool eph)
+{
+ struct zbudpage *zbudpage = NULL, *zbudpag2;
+ struct tmem_handle *thfrom;
+ char *from_va;
+ void *zbpg;
+ unsigned size;
+ int ret = 0, i;
+ spinlock_t *lists_lock =
+ eph ? &zbud_eph_lists_lock : &zbud_pers_lists_lock;
+ struct list_head *lru_list =
+ eph ? &zbud_eph_lru_list : &zbud_pers_lru_list;
+
+ spin_lock_bh(lists_lock);
+ if (list_empty(lru_list))
+ goto out;
+ list_for_each_entry_safe(zbudpage, zbudpag2, lru_list, lru) {
+ /* skip a locked zbudpage */
+ if (unlikely(!zbudpage_spin_trylock(zbudpage)))
+ continue;
+ /* skip an unevictable zbudpage */
+ if (unlikely(zbudpage->unevictable != 0)) {
+ zbudpage_spin_unlock(zbudpage);
+ continue;
+ }
+ /* got a locked evictable page */
+ goto zombify_page;
+ }
+ /* no unlocked evictable pages, give up */
+ goto out;
+
+zombify_page:
+ /* got an unlocked evictable page, zombify it */
+ list_del_init(&zbudpage->budlist);
+ zbudpage_set_zombie(zbudpage);
+ /* FIXME what accounting do I need to do here? */
+ list_del_init(&zbudpage->lru);
+ if (eph) {
+ list_add_tail(&zbudpage->lru, &zbud_eph_zombie_list);
+ zbud_eph_zombie_count =
+ atomic_inc_return(&zbud_eph_zombie_atomic);
+ } else {
+ list_add_tail(&zbudpage->lru, &zbud_pers_zombie_list);
+ zbud_pers_zombie_count =
+ atomic_inc_return(&zbud_pers_zombie_atomic);
+ }
+ /* FIXME what accounting do I need to do here? */
+ zbpg = kmap_zbudpage_atomic(zbudpage);
+ for (i = 0; i < 2; i++) {
+ size = (i == 0) ? zbudpage->zbud0_size : zbudpage->zbud1_size;
+ if (size) {
+ from_va = zbud_data(zbpg, i, size);
+ thfrom = (struct tmem_handle *)from_va;
+ from_va += sizeof(struct tmem_handle);
+ size -= sizeof(struct tmem_handle);
+ if (th != NULL)
+ th[ret] = *thfrom;
+ if (data != NULL)
+ memcpy(data[ret], from_va, size);
+ if (zsize != NULL)
+ *zsize++ = size;
+ ret++;
+ }
+ }
+ kunmap_zbudpage_atomic(zbpg);
+ zbudpage_spin_unlock(zbudpage);
+out:
+ spin_unlock_bh(lists_lock);
+ return ret;
+}
+
+void __init zbud_init(void)
+{
+ int i;
+
+#ifdef CONFIG_DEBUG_FS
+ zbud_debugfs_init();
+#endif
+ BUG_ON((sizeof(struct tmem_handle) * 2 > CHUNK_SIZE));
+ BUG_ON(sizeof(struct zbudpage) > sizeof(struct page));
+ for (i = 0; i < NCHUNKS; i++) {
+ INIT_LIST_HEAD(&zbud_eph_unbuddied[i].list);
+ INIT_LIST_HEAD(&zbud_pers_unbuddied[i].list);
+ }
+}
--- /dev/null
+/*
+ * zbud.h
+ *
+ * Copyright (c) 2010-2012, Dan Magenheimer, Oracle Corp.
+ *
+ */
+
+#ifndef _ZBUD_H_
+#define _ZBUD_H_
+
+#include "tmem.h"
+
+struct zbudref;
+
+extern unsigned int zbud_max_buddy_size(void);
+extern struct zbudref *zbud_match_prep(struct tmem_handle *th, bool eph,
+ void *cdata, unsigned size);
+extern struct zbudref *zbud_create_prep(struct tmem_handle *th, bool eph,
+ void *cdata, unsigned size,
+ struct page *newpage);
+extern void zbud_create_finish(struct zbudref *, bool);
+extern int zbud_decompress(struct page *, struct zbudref *, bool,
+ void (*func)(char *, unsigned int, char *));
+extern int zbud_copy_from_zbud(char *, struct zbudref *, size_t *, bool);
+extern int zbud_copy_to_zbud(struct zbudref *, char *, bool);
+extern struct page *zbud_free_and_delist(struct zbudref *, bool eph,
+ unsigned int *, unsigned int *);
+extern struct page *zbud_evict_pageframe_lru(unsigned int *, unsigned int *);
+extern unsigned int zbud_make_zombie_lru(struct tmem_handle *, unsigned char **,
+ unsigned int *, bool);
+extern void zbud_init(void);
+
+#endif /* _ZBUD_H_ */
--- /dev/null
+/*
+ * zcache.c
+ *
+ * Copyright (c) 2010-2012, Dan Magenheimer, Oracle Corp.
+ * Copyright (c) 2010,2011, Nitin Gupta
+ *
+ * Zcache provides an in-kernel "host implementation" for transcendent memory
+ * ("tmem") and, thus indirectly, for cleancache and frontswap. Zcache uses
+ * lzo1x compression to improve density and an embedded allocator called
+ * "zbud" which "buddies" two compressed pages semi-optimally in each physical
+ * pageframe. Zbud is integrally tied into tmem to allow pageframes to
+ * be "reclaimed" efficiently.
+ */
+
+#include <linux/module.h>
+#include <linux/cpu.h>
+#include <linux/highmem.h>
+#include <linux/list.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/types.h>
+#include <linux/atomic.h>
+#include <linux/math64.h>
+#include <linux/crypto.h>
+
+#include <linux/cleancache.h>
+#include <linux/frontswap.h>
+#include "tmem.h"
+#include "zcache.h"
+#include "zbud.h"
+#include "ramster.h"
+#ifdef CONFIG_RAMSTER
+static int ramster_enabled;
+#else
+#define ramster_enabled 0
+#endif
+
+#ifndef __PG_WAS_ACTIVE
+static inline bool PageWasActive(struct page *page)
+{
+ return true;
+}
+
+static inline void SetPageWasActive(struct page *page)
+{
+}
+#endif
+
+#ifdef FRONTSWAP_HAS_EXCLUSIVE_GETS
+static bool frontswap_has_exclusive_gets __read_mostly = true;
+#else
+static bool frontswap_has_exclusive_gets __read_mostly;
+static inline void frontswap_tmem_exclusive_gets(bool b)
+{
+}
+#endif
+
+static int zcache_enabled __read_mostly;
+static int disable_cleancache __read_mostly;
+static int disable_frontswap __read_mostly;
+static int disable_frontswap_ignore_nonactive __read_mostly;
+static int disable_cleancache_ignore_nonactive __read_mostly;
+static char *namestr __read_mostly = "zcache";
+
+#define ZCACHE_GFP_MASK \
+ (__GFP_FS | __GFP_NORETRY | __GFP_NOWARN | __GFP_NOMEMALLOC)
+
+MODULE_LICENSE("GPL");
+
+/* crypto API for zcache */
+#define ZCACHE_COMP_NAME_SZ CRYPTO_MAX_ALG_NAME
+static char zcache_comp_name[ZCACHE_COMP_NAME_SZ] __read_mostly;
+static struct crypto_comp * __percpu *zcache_comp_pcpu_tfms __read_mostly;
+
+enum comp_op {
+ ZCACHE_COMPOP_COMPRESS,
+ ZCACHE_COMPOP_DECOMPRESS
+};
+
+static inline int zcache_comp_op(enum comp_op op,
+ const u8 *src, unsigned int slen,
+ u8 *dst, unsigned int *dlen)
+{
+ struct crypto_comp *tfm;
+ int ret = -1;
+
+ BUG_ON(!zcache_comp_pcpu_tfms);
+ tfm = *per_cpu_ptr(zcache_comp_pcpu_tfms, get_cpu());
+ BUG_ON(!tfm);
+ switch (op) {
+ case ZCACHE_COMPOP_COMPRESS:
+ ret = crypto_comp_compress(tfm, src, slen, dst, dlen);
+ break;
+ case ZCACHE_COMPOP_DECOMPRESS:
+ ret = crypto_comp_decompress(tfm, src, slen, dst, dlen);
+ break;
+ default:
+ ret = -EINVAL;
+ }
+ put_cpu();
+ return ret;
+}
+
+/*
+ * policy parameters
+ */
+
+/*
+ * byte count defining poor compression; pages with greater zsize will be
+ * rejected
+ */
+static unsigned int zbud_max_zsize __read_mostly = (PAGE_SIZE / 8) * 7;
+/*
+ * byte count defining poor *mean* compression; pages with greater zsize
+ * will be rejected until sufficient better-compressed pages are accepted
+ * driving the mean below this threshold
+ */
+static unsigned int zbud_max_mean_zsize __read_mostly = (PAGE_SIZE / 8) * 5;
+
+/*
+ * for now, used named slabs so can easily track usage; later can
+ * either just use kmalloc, or perhaps add a slab-like allocator
+ * to more carefully manage total memory utilization
+ */
+static struct kmem_cache *zcache_objnode_cache;
+static struct kmem_cache *zcache_obj_cache;
+
+static DEFINE_PER_CPU(struct zcache_preload, zcache_preloads) = { 0, };
+
+/* we try to keep these statistics SMP-consistent */
+static long zcache_obj_count;
+static atomic_t zcache_obj_atomic = ATOMIC_INIT(0);
+static long zcache_obj_count_max;
+static long zcache_objnode_count;
+static atomic_t zcache_objnode_atomic = ATOMIC_INIT(0);
+static long zcache_objnode_count_max;
+static u64 zcache_eph_zbytes;
+static atomic_long_t zcache_eph_zbytes_atomic = ATOMIC_INIT(0);
+static u64 zcache_eph_zbytes_max;
+static u64 zcache_pers_zbytes;
+static atomic_long_t zcache_pers_zbytes_atomic = ATOMIC_INIT(0);
+static u64 zcache_pers_zbytes_max;
+static long zcache_eph_pageframes;
+static atomic_t zcache_eph_pageframes_atomic = ATOMIC_INIT(0);
+static long zcache_eph_pageframes_max;
+static long zcache_pers_pageframes;
+static atomic_t zcache_pers_pageframes_atomic = ATOMIC_INIT(0);
+static long zcache_pers_pageframes_max;
+static long zcache_pageframes_alloced;
+static atomic_t zcache_pageframes_alloced_atomic = ATOMIC_INIT(0);
+static long zcache_pageframes_freed;
+static atomic_t zcache_pageframes_freed_atomic = ATOMIC_INIT(0);
+static long zcache_eph_zpages;
+static atomic_t zcache_eph_zpages_atomic = ATOMIC_INIT(0);
+static long zcache_eph_zpages_max;
+static long zcache_pers_zpages;
+static atomic_t zcache_pers_zpages_atomic = ATOMIC_INIT(0);
+static long zcache_pers_zpages_max;
+
+/* but for the rest of these, counting races are ok */
+static unsigned long zcache_flush_total;
+static unsigned long zcache_flush_found;
+static unsigned long zcache_flobj_total;
+static unsigned long zcache_flobj_found;
+static unsigned long zcache_failed_eph_puts;
+static unsigned long zcache_failed_pers_puts;
+static unsigned long zcache_failed_getfreepages;
+static unsigned long zcache_failed_alloc;
+static unsigned long zcache_put_to_flush;
+static unsigned long zcache_compress_poor;
+static unsigned long zcache_mean_compress_poor;
+static unsigned long zcache_eph_ate_tail;
+static unsigned long zcache_eph_ate_tail_failed;
+static unsigned long zcache_pers_ate_eph;
+static unsigned long zcache_pers_ate_eph_failed;
+static unsigned long zcache_evicted_eph_zpages;
+static unsigned long zcache_evicted_eph_pageframes;
+static unsigned long zcache_last_active_file_pageframes;
+static unsigned long zcache_last_inactive_file_pageframes;
+static unsigned long zcache_last_active_anon_pageframes;
+static unsigned long zcache_last_inactive_anon_pageframes;
+static unsigned long zcache_eph_nonactive_puts_ignored;
+static unsigned long zcache_pers_nonactive_puts_ignored;
+
+#ifdef CONFIG_DEBUG_FS
+#include <linux/debugfs.h>
+#define zdfs debugfs_create_size_t
+#define zdfs64 debugfs_create_u64
+static int zcache_debugfs_init(void)
+{
+ struct dentry *root = debugfs_create_dir("zcache", NULL);
+ if (root == NULL)
+ return -ENXIO;
+
+ zdfs("obj_count", S_IRUGO, root, &zcache_obj_count);
+ zdfs("obj_count_max", S_IRUGO, root, &zcache_obj_count_max);
+ zdfs("objnode_count", S_IRUGO, root, &zcache_objnode_count);
+ zdfs("objnode_count_max", S_IRUGO, root, &zcache_objnode_count_max);
+ zdfs("flush_total", S_IRUGO, root, &zcache_flush_total);
+ zdfs("flush_found", S_IRUGO, root, &zcache_flush_found);
+ zdfs("flobj_total", S_IRUGO, root, &zcache_flobj_total);
+ zdfs("flobj_found", S_IRUGO, root, &zcache_flobj_found);
+ zdfs("failed_eph_puts", S_IRUGO, root, &zcache_failed_eph_puts);
+ zdfs("failed_pers_puts", S_IRUGO, root, &zcache_failed_pers_puts);
+ zdfs("failed_get_free_pages", S_IRUGO, root,
+ &zcache_failed_getfreepages);
+ zdfs("failed_alloc", S_IRUGO, root, &zcache_failed_alloc);
+ zdfs("put_to_flush", S_IRUGO, root, &zcache_put_to_flush);
+ zdfs("compress_poor", S_IRUGO, root, &zcache_compress_poor);
+ zdfs("mean_compress_poor", S_IRUGO, root, &zcache_mean_compress_poor);
+ zdfs("eph_ate_tail", S_IRUGO, root, &zcache_eph_ate_tail);
+ zdfs("eph_ate_tail_failed", S_IRUGO, root, &zcache_eph_ate_tail_failed);
+ zdfs("pers_ate_eph", S_IRUGO, root, &zcache_pers_ate_eph);
+ zdfs("pers_ate_eph_failed", S_IRUGO, root, &zcache_pers_ate_eph_failed);
+ zdfs("evicted_eph_zpages", S_IRUGO, root, &zcache_evicted_eph_zpages);
+ zdfs("evicted_eph_pageframes", S_IRUGO, root,
+ &zcache_evicted_eph_pageframes);
+ zdfs("eph_pageframes", S_IRUGO, root, &zcache_eph_pageframes);
+ zdfs("eph_pageframes_max", S_IRUGO, root, &zcache_eph_pageframes_max);
+ zdfs("pers_pageframes", S_IRUGO, root, &zcache_pers_pageframes);
+ zdfs("pers_pageframes_max", S_IRUGO, root, &zcache_pers_pageframes_max);
+ zdfs("eph_zpages", S_IRUGO, root, &zcache_eph_zpages);
+ zdfs("eph_zpages_max", S_IRUGO, root, &zcache_eph_zpages_max);
+ zdfs("pers_zpages", S_IRUGO, root, &zcache_pers_zpages);
+ zdfs("pers_zpages_max", S_IRUGO, root, &zcache_pers_zpages_max);
+ zdfs("last_active_file_pageframes", S_IRUGO, root,
+ &zcache_last_active_file_pageframes);
+ zdfs("last_inactive_file_pageframes", S_IRUGO, root,
+ &zcache_last_inactive_file_pageframes);
+ zdfs("last_active_anon_pageframes", S_IRUGO, root,
+ &zcache_last_active_anon_pageframes);
+ zdfs("last_inactive_anon_pageframes", S_IRUGO, root,
+ &zcache_last_inactive_anon_pageframes);
+ zdfs("eph_nonactive_puts_ignored", S_IRUGO, root,
+ &zcache_eph_nonactive_puts_ignored);
+ zdfs("pers_nonactive_puts_ignored", S_IRUGO, root,
+ &zcache_pers_nonactive_puts_ignored);
+ zdfs64("eph_zbytes", S_IRUGO, root, &zcache_eph_zbytes);
+ zdfs64("eph_zbytes_max", S_IRUGO, root, &zcache_eph_zbytes_max);
+ zdfs64("pers_zbytes", S_IRUGO, root, &zcache_pers_zbytes);
+ zdfs64("pers_zbytes_max", S_IRUGO, root, &zcache_pers_zbytes_max);
+ return 0;
+}
+#undef zdebugfs
+#undef zdfs64
+#endif
+
+#define ZCACHE_DEBUG
+#ifdef ZCACHE_DEBUG
+/* developers can call this in case of ooms, e.g. to find memory leaks */
+void zcache_dump(void)
+{
+ pr_info("zcache: obj_count=%lu\n", zcache_obj_count);
+ pr_info("zcache: obj_count_max=%lu\n", zcache_obj_count_max);
+ pr_info("zcache: objnode_count=%lu\n", zcache_objnode_count);
+ pr_info("zcache: objnode_count_max=%lu\n", zcache_objnode_count_max);
+ pr_info("zcache: flush_total=%lu\n", zcache_flush_total);
+ pr_info("zcache: flush_found=%lu\n", zcache_flush_found);
+ pr_info("zcache: flobj_total=%lu\n", zcache_flobj_total);
+ pr_info("zcache: flobj_found=%lu\n", zcache_flobj_found);
+ pr_info("zcache: failed_eph_puts=%lu\n", zcache_failed_eph_puts);
+ pr_info("zcache: failed_pers_puts=%lu\n", zcache_failed_pers_puts);
+ pr_info("zcache: failed_get_free_pages=%lu\n",
+ zcache_failed_getfreepages);
+ pr_info("zcache: failed_alloc=%lu\n", zcache_failed_alloc);
+ pr_info("zcache: put_to_flush=%lu\n", zcache_put_to_flush);
+ pr_info("zcache: compress_poor=%lu\n", zcache_compress_poor);
+ pr_info("zcache: mean_compress_poor=%lu\n",
+ zcache_mean_compress_poor);
+ pr_info("zcache: eph_ate_tail=%lu\n", zcache_eph_ate_tail);
+ pr_info("zcache: eph_ate_tail_failed=%lu\n",
+ zcache_eph_ate_tail_failed);
+ pr_info("zcache: pers_ate_eph=%lu\n", zcache_pers_ate_eph);
+ pr_info("zcache: pers_ate_eph_failed=%lu\n",
+ zcache_pers_ate_eph_failed);
+ pr_info("zcache: evicted_eph_zpages=%lu\n", zcache_evicted_eph_zpages);
+ pr_info("zcache: evicted_eph_pageframes=%lu\n",
+ zcache_evicted_eph_pageframes);
+ pr_info("zcache: eph_pageframes=%lu\n", zcache_eph_pageframes);
+ pr_info("zcache: eph_pageframes_max=%lu\n", zcache_eph_pageframes_max);
+ pr_info("zcache: pers_pageframes=%lu\n", zcache_pers_pageframes);
+ pr_info("zcache: pers_pageframes_max=%lu\n",
+ zcache_pers_pageframes_max);
+ pr_info("zcache: eph_zpages=%lu\n", zcache_eph_zpages);
+ pr_info("zcache: eph_zpages_max=%lu\n", zcache_eph_zpages_max);
+ pr_info("zcache: pers_zpages=%lu\n", zcache_pers_zpages);
+ pr_info("zcache: pers_zpages_max=%lu\n", zcache_pers_zpages_max);
+ pr_info("zcache: eph_zbytes=%llu\n",
+ (unsigned long long)zcache_eph_zbytes);
+ pr_info("zcache: eph_zbytes_max=%llu\n",
+ (unsigned long long)zcache_eph_zbytes_max);
+ pr_info("zcache: pers_zbytes=%llu\n",
+ (unsigned long long)zcache_pers_zbytes);
+ pr_info("zcache: pers_zbytes_max=%llu\n",
+ (unsigned long long)zcache_pers_zbytes_max);
+}
+#endif
+
+/*
+ * zcache core code starts here
+ */
+
+static struct zcache_client zcache_host;
+static struct zcache_client zcache_clients[MAX_CLIENTS];
+
+static inline bool is_local_client(struct zcache_client *cli)
+{
+ return cli == &zcache_host;
+}
+
+static struct zcache_client *zcache_get_client_by_id(uint16_t cli_id)
+{
+ struct zcache_client *cli = &zcache_host;
+
+ if (cli_id != LOCAL_CLIENT) {
+ if (cli_id >= MAX_CLIENTS)
+ goto out;
+ cli = &zcache_clients[cli_id];
+ }
+out:
+ return cli;
+}
+
+/*
+ * Tmem operations assume the poolid implies the invoking client.
+ * Zcache only has one client (the kernel itself): LOCAL_CLIENT.
+ * RAMster has each client numbered by cluster node, and a KVM version
+ * of zcache would have one client per guest and each client might
+ * have a poolid==N.
+ */
+struct tmem_pool *zcache_get_pool_by_id(uint16_t cli_id, uint16_t poolid)
+{
+ struct tmem_pool *pool = NULL;
+ struct zcache_client *cli = NULL;
+
+ cli = zcache_get_client_by_id(cli_id);
+ if (cli == NULL)
+ goto out;
+ if (!is_local_client(cli))
+ atomic_inc(&cli->refcount);
+ if (poolid < MAX_POOLS_PER_CLIENT) {
+ pool = cli->tmem_pools[poolid];
+ if (pool != NULL)
+ atomic_inc(&pool->refcount);
+ }
+out:
+ return pool;
+}
+
+void zcache_put_pool(struct tmem_pool *pool)
+{
+ struct zcache_client *cli = NULL;
+
+ if (pool == NULL)
+ BUG();
+ cli = pool->client;
+ atomic_dec(&pool->refcount);
+ if (!is_local_client(cli))
+ atomic_dec(&cli->refcount);
+}
+
+int zcache_new_client(uint16_t cli_id)
+{
+ struct zcache_client *cli;
+ int ret = -1;
+
+ cli = zcache_get_client_by_id(cli_id);
+ if (cli == NULL)
+ goto out;
+ if (cli->allocated)
+ goto out;
+ cli->allocated = 1;
+ ret = 0;
+out:
+ return ret;
+}
+
+/*
+ * zcache implementation for tmem host ops
+ */
+
+static struct tmem_objnode *zcache_objnode_alloc(struct tmem_pool *pool)
+{
+ struct tmem_objnode *objnode = NULL;
+ struct zcache_preload *kp;
+ int i;
+
+ kp = &__get_cpu_var(zcache_preloads);
+ for (i = 0; i < ARRAY_SIZE(kp->objnodes); i++) {
+ objnode = kp->objnodes[i];
+ if (objnode != NULL) {
+ kp->objnodes[i] = NULL;
+ break;
+ }
+ }
+ BUG_ON(objnode == NULL);
+ zcache_objnode_count = atomic_inc_return(&zcache_objnode_atomic);
+ if (zcache_objnode_count > zcache_objnode_count_max)
+ zcache_objnode_count_max = zcache_objnode_count;
+ return objnode;
+}
+
+static void zcache_objnode_free(struct tmem_objnode *objnode,
+ struct tmem_pool *pool)
+{
+ zcache_objnode_count =
+ atomic_dec_return(&zcache_objnode_atomic);
+ BUG_ON(zcache_objnode_count < 0);
+ kmem_cache_free(zcache_objnode_cache, objnode);
+}
+
+static struct tmem_obj *zcache_obj_alloc(struct tmem_pool *pool)
+{
+ struct tmem_obj *obj = NULL;
+ struct zcache_preload *kp;
+
+ kp = &__get_cpu_var(zcache_preloads);
+ obj = kp->obj;
+ BUG_ON(obj == NULL);
+ kp->obj = NULL;
+ zcache_obj_count = atomic_inc_return(&zcache_obj_atomic);
+ if (zcache_obj_count > zcache_obj_count_max)
+ zcache_obj_count_max = zcache_obj_count;
+ return obj;
+}
+
+static void zcache_obj_free(struct tmem_obj *obj, struct tmem_pool *pool)
+{
+ zcache_obj_count =
+ atomic_dec_return(&zcache_obj_atomic);
+ BUG_ON(zcache_obj_count < 0);
+ kmem_cache_free(zcache_obj_cache, obj);
+}
+
+static struct tmem_hostops zcache_hostops = {
+ .obj_alloc = zcache_obj_alloc,
+ .obj_free = zcache_obj_free,
+ .objnode_alloc = zcache_objnode_alloc,
+ .objnode_free = zcache_objnode_free,
+};
+
+static struct page *zcache_alloc_page(void)
+{
+ struct page *page = alloc_page(ZCACHE_GFP_MASK);
+
+ if (page != NULL)
+ zcache_pageframes_alloced =
+ atomic_inc_return(&zcache_pageframes_alloced_atomic);
+ return page;
+}
+
+static void zcache_unacct_page(void)
+{
+ zcache_pageframes_freed =
+ atomic_inc_return(&zcache_pageframes_freed_atomic);
+}
+
+static void zcache_free_page(struct page *page)
+{
+ long curr_pageframes;
+ static long max_pageframes, min_pageframes, total_freed;
+
+ if (page == NULL)
+ BUG();
+ __free_page(page);
+ zcache_pageframes_freed =
+ atomic_inc_return(&zcache_pageframes_freed_atomic);
+ curr_pageframes = zcache_pageframes_alloced -
+ atomic_read(&zcache_pageframes_freed_atomic) -
+ atomic_read(&zcache_eph_pageframes_atomic) -
+ atomic_read(&zcache_pers_pageframes_atomic);
+ if (curr_pageframes > max_pageframes)
+ max_pageframes = curr_pageframes;
+ if (curr_pageframes < min_pageframes)
+ min_pageframes = curr_pageframes;
+#ifdef ZCACHE_DEBUG
+ if (curr_pageframes > 2L || curr_pageframes < -2L) {
+ /* pr_info here */
+ }
+#endif
+}
+
+/*
+ * zcache implementations for PAM page descriptor ops
+ */
+
+/* forward reference */
+static void zcache_compress(struct page *from,
+ void **out_va, unsigned *out_len);
+
+static struct page *zcache_evict_eph_pageframe(void);
+
+static void *zcache_pampd_eph_create(char *data, size_t size, bool raw,
+ struct tmem_handle *th)
+{
+ void *pampd = NULL, *cdata = data;
+ unsigned clen = size;
+ struct page *page = (struct page *)(data), *newpage;
+
+ if (!raw) {
+ zcache_compress(page, &cdata, &clen);
+ if (clen > zbud_max_buddy_size()) {
+ zcache_compress_poor++;
+ goto out;
+ }
+ } else {
+ BUG_ON(clen > zbud_max_buddy_size());
+ }
+
+ /* look for space via an existing match first */
+ pampd = (void *)zbud_match_prep(th, true, cdata, clen);
+ if (pampd != NULL)
+ goto got_pampd;
+
+ /* no match, now we need to find (or free up) a full page */
+ newpage = zcache_alloc_page();
+ if (newpage != NULL)
+ goto create_in_new_page;
+
+ zcache_failed_getfreepages++;
+ /* can't allocate a page, evict an ephemeral page via LRU */
+ newpage = zcache_evict_eph_pageframe();
+ if (newpage == NULL) {
+ zcache_eph_ate_tail_failed++;
+ goto out;
+ }
+ zcache_eph_ate_tail++;
+
+create_in_new_page:
+ pampd = (void *)zbud_create_prep(th, true, cdata, clen, newpage);
+ BUG_ON(pampd == NULL);
+ zcache_eph_pageframes =
+ atomic_inc_return(&zcache_eph_pageframes_atomic);
+ if (zcache_eph_pageframes > zcache_eph_pageframes_max)
+ zcache_eph_pageframes_max = zcache_eph_pageframes;
+
+got_pampd:
+ zcache_eph_zbytes =
+ atomic_long_add_return(clen, &zcache_eph_zbytes_atomic);
+ if (zcache_eph_zbytes > zcache_eph_zbytes_max)
+ zcache_eph_zbytes_max = zcache_eph_zbytes;
+ zcache_eph_zpages = atomic_inc_return(&zcache_eph_zpages_atomic);
+ if (zcache_eph_zpages > zcache_eph_zpages_max)
+ zcache_eph_zpages_max = zcache_eph_zpages;
+ if (ramster_enabled && raw)
+ ramster_count_foreign_pages(true, 1);
+out:
+ return pampd;
+}
+
+static void *zcache_pampd_pers_create(char *data, size_t size, bool raw,
+ struct tmem_handle *th)
+{
+ void *pampd = NULL, *cdata = data;
+ unsigned clen = size;
+ struct page *page = (struct page *)(data), *newpage;
+ unsigned long zbud_mean_zsize;
+ unsigned long curr_pers_zpages, total_zsize;
+
+ if (data == NULL) {
+ BUG_ON(!ramster_enabled);
+ goto create_pampd;
+ }
+ curr_pers_zpages = zcache_pers_zpages;
+/* FIXME CONFIG_RAMSTER... subtract atomic remote_pers_pages here? */
+ if (!raw)
+ zcache_compress(page, &cdata, &clen);
+ /* reject if compression is too poor */
+ if (clen > zbud_max_zsize) {
+ zcache_compress_poor++;
+ goto out;
+ }
+ /* reject if mean compression is too poor */
+ if ((clen > zbud_max_mean_zsize) && (curr_pers_zpages > 0)) {
+ total_zsize = zcache_pers_zbytes;
+ if ((long)total_zsize < 0)
+ total_zsize = 0;
+ zbud_mean_zsize = div_u64(total_zsize,
+ curr_pers_zpages);
+ if (zbud_mean_zsize > zbud_max_mean_zsize) {
+ zcache_mean_compress_poor++;
+ goto out;
+ }
+ }
+
+create_pampd:
+ /* look for space via an existing match first */
+ pampd = (void *)zbud_match_prep(th, false, cdata, clen);
+ if (pampd != NULL)
+ goto got_pampd;
+
+ /* no match, now we need to find (or free up) a full page */
+ newpage = zcache_alloc_page();
+ if (newpage != NULL)
+ goto create_in_new_page;
+ /*
+ * FIXME do the following only if eph is oversized?
+ * if (zcache_eph_pageframes >
+ * (global_page_state(NR_LRU_BASE + LRU_ACTIVE_FILE) +
+ * global_page_state(NR_LRU_BASE + LRU_INACTIVE_FILE)))
+ */
+ zcache_failed_getfreepages++;
+ /* can't allocate a page, evict an ephemeral page via LRU */
+ newpage = zcache_evict_eph_pageframe();
+ if (newpage == NULL) {
+ zcache_pers_ate_eph_failed++;
+ goto out;
+ }
+ zcache_pers_ate_eph++;
+
+create_in_new_page:
+ pampd = (void *)zbud_create_prep(th, false, cdata, clen, newpage);
+ BUG_ON(pampd == NULL);
+ zcache_pers_pageframes =
+ atomic_inc_return(&zcache_pers_pageframes_atomic);
+ if (zcache_pers_pageframes > zcache_pers_pageframes_max)
+ zcache_pers_pageframes_max = zcache_pers_pageframes;
+
+got_pampd:
+ zcache_pers_zpages = atomic_inc_return(&zcache_pers_zpages_atomic);
+ if (zcache_pers_zpages > zcache_pers_zpages_max)
+ zcache_pers_zpages_max = zcache_pers_zpages;
+ zcache_pers_zbytes =
+ atomic_long_add_return(clen, &zcache_pers_zbytes_atomic);
+ if (zcache_pers_zbytes > zcache_pers_zbytes_max)
+ zcache_pers_zbytes_max = zcache_pers_zbytes;
+ if (ramster_enabled && raw)
+ ramster_count_foreign_pages(false, 1);
+out:
+ return pampd;
+}
+
+/*
+ * This is called directly from zcache_put_page to pre-allocate space
+ * to store a zpage.
+ */
+void *zcache_pampd_create(char *data, unsigned int size, bool raw,
+ int eph, struct tmem_handle *th)
+{
+ void *pampd = NULL;
+ struct zcache_preload *kp;
+ struct tmem_objnode *objnode;
+ struct tmem_obj *obj;
+ int i;
+
+ BUG_ON(!irqs_disabled());
+ /* pre-allocate per-cpu metadata */
+ BUG_ON(zcache_objnode_cache == NULL);
+ BUG_ON(zcache_obj_cache == NULL);
+ kp = &__get_cpu_var(zcache_preloads);
+ for (i = 0; i < ARRAY_SIZE(kp->objnodes); i++) {
+ objnode = kp->objnodes[i];
+ if (objnode == NULL) {
+ objnode = kmem_cache_alloc(zcache_objnode_cache,
+ ZCACHE_GFP_MASK);
+ if (unlikely(objnode == NULL)) {
+ zcache_failed_alloc++;
+ goto out;
+ }
+ kp->objnodes[i] = objnode;
+ }
+ }
+ if (kp->obj == NULL) {
+ obj = kmem_cache_alloc(zcache_obj_cache, ZCACHE_GFP_MASK);
+ kp->obj = obj;
+ }
+ if (unlikely(kp->obj == NULL)) {
+ zcache_failed_alloc++;
+ goto out;
+ }
+ /*
+ * ok, have all the metadata pre-allocated, now do the data
+ * but since how we allocate the data is dependent on ephemeral
+ * or persistent, we split the call here to different sub-functions
+ */
+ if (eph)
+ pampd = zcache_pampd_eph_create(data, size, raw, th);
+ else
+ pampd = zcache_pampd_pers_create(data, size, raw, th);
+out:
+ return pampd;
+}
+
+/*
+ * This is a pamops called via tmem_put and is necessary to "finish"
+ * a pampd creation.
+ */
+void zcache_pampd_create_finish(void *pampd, bool eph)
+{
+ zbud_create_finish((struct zbudref *)pampd, eph);
+}
+
+/*
+ * This is passed as a function parameter to zbud_decompress so that
+ * zbud need not be familiar with the details of crypto. It assumes that
+ * the bytes from_va and to_va through from_va+size-1 and to_va+size-1 are
+ * kmapped. It must be successful, else there is a logic bug somewhere.
+ */
+static void zcache_decompress(char *from_va, unsigned int size, char *to_va)
+{
+ int ret;
+ unsigned int outlen = PAGE_SIZE;
+
+ ret = zcache_comp_op(ZCACHE_COMPOP_DECOMPRESS, from_va, size,
+ to_va, &outlen);
+ BUG_ON(ret);
+ BUG_ON(outlen != PAGE_SIZE);
+}
+
+/*
+ * Decompress from the kernel va to a pageframe
+ */
+void zcache_decompress_to_page(char *from_va, unsigned int size,
+ struct page *to_page)
+{
+ char *to_va = kmap_atomic(to_page);
+ zcache_decompress(from_va, size, to_va);
+ kunmap_atomic(to_va);
+}
+
+/*
+ * fill the pageframe corresponding to the struct page with the data
+ * from the passed pampd
+ */
+static int zcache_pampd_get_data(char *data, size_t *sizep, bool raw,
+ void *pampd, struct tmem_pool *pool,
+ struct tmem_oid *oid, uint32_t index)
+{
+ int ret;
+ bool eph = !is_persistent(pool);
+
+ BUG_ON(preemptible());
+ BUG_ON(eph); /* fix later if shared pools get implemented */
+ BUG_ON(pampd_is_remote(pampd));
+ if (raw)
+ ret = zbud_copy_from_zbud(data, (struct zbudref *)pampd,
+ sizep, eph);
+ else {
+ ret = zbud_decompress((struct page *)(data),
+ (struct zbudref *)pampd, false,
+ zcache_decompress);
+ *sizep = PAGE_SIZE;
+ }
+ return ret;
+}
+
+/*
+ * fill the pageframe corresponding to the struct page with the data
+ * from the passed pampd
+ */
+static int zcache_pampd_get_data_and_free(char *data, size_t *sizep, bool raw,
+ void *pampd, struct tmem_pool *pool,
+ struct tmem_oid *oid, uint32_t index)
+{
+ int ret;
+ bool eph = !is_persistent(pool);
+ struct page *page = NULL;
+ unsigned int zsize, zpages;
+
+ BUG_ON(preemptible());
+ BUG_ON(pampd_is_remote(pampd));
+ if (raw)
+ ret = zbud_copy_from_zbud(data, (struct zbudref *)pampd,
+ sizep, eph);
+ else {
+ ret = zbud_decompress((struct page *)(data),
+ (struct zbudref *)pampd, eph,
+ zcache_decompress);
+ *sizep = PAGE_SIZE;
+ }
+ page = zbud_free_and_delist((struct zbudref *)pampd, eph,
+ &zsize, &zpages);
+ if (eph) {
+ if (page)
+ zcache_eph_pageframes =
+ atomic_dec_return(&zcache_eph_pageframes_atomic);
+ zcache_eph_zpages =
+ atomic_sub_return(zpages, &zcache_eph_zpages_atomic);
+ zcache_eph_zbytes =
+ atomic_long_sub_return(zsize, &zcache_eph_zbytes_atomic);
+ } else {
+ if (page)
+ zcache_pers_pageframes =
+ atomic_dec_return(&zcache_pers_pageframes_atomic);
+ zcache_pers_zpages =
+ atomic_sub_return(zpages, &zcache_pers_zpages_atomic);
+ zcache_pers_zbytes =
+ atomic_long_sub_return(zsize, &zcache_pers_zbytes_atomic);
+ }
+ if (!is_local_client(pool->client))
+ ramster_count_foreign_pages(eph, -1);
+ if (page)
+ zcache_free_page(page);
+ return ret;
+}
+
+/*
+ * free the pampd and remove it from any zcache lists
+ * pampd must no longer be pointed to from any tmem data structures!
+ */
+static void zcache_pampd_free(void *pampd, struct tmem_pool *pool,
+ struct tmem_oid *oid, uint32_t index, bool acct)
+{
+ struct page *page = NULL;
+ unsigned int zsize, zpages;
+
+ BUG_ON(preemptible());
+ if (pampd_is_remote(pampd)) {
+ BUG_ON(!ramster_enabled);
+ pampd = ramster_pampd_free(pampd, pool, oid, index, acct);
+ if (pampd == NULL)
+ return;
+ }
+ if (is_ephemeral(pool)) {
+ page = zbud_free_and_delist((struct zbudref *)pampd,
+ true, &zsize, &zpages);
+ if (page)
+ zcache_eph_pageframes =
+ atomic_dec_return(&zcache_eph_pageframes_atomic);
+ zcache_eph_zpages =
+ atomic_sub_return(zpages, &zcache_eph_zpages_atomic);
+ zcache_eph_zbytes =
+ atomic_long_sub_return(zsize, &zcache_eph_zbytes_atomic);
+ /* FIXME CONFIG_RAMSTER... check acct parameter? */
+ } else {
+ page = zbud_free_and_delist((struct zbudref *)pampd,
+ false, &zsize, &zpages);
+ if (page)
+ zcache_pers_pageframes =
+ atomic_dec_return(&zcache_pers_pageframes_atomic);
+ zcache_pers_zpages =
+ atomic_sub_return(zpages, &zcache_pers_zpages_atomic);
+ zcache_pers_zbytes =
+ atomic_long_sub_return(zsize, &zcache_pers_zbytes_atomic);
+ }
+ if (!is_local_client(pool->client))
+ ramster_count_foreign_pages(is_ephemeral(pool), -1);
+ if (page)
+ zcache_free_page(page);
+}
+
+static struct tmem_pamops zcache_pamops = {
+ .create_finish = zcache_pampd_create_finish,
+ .get_data = zcache_pampd_get_data,
+ .get_data_and_free = zcache_pampd_get_data_and_free,
+ .free = zcache_pampd_free,
+};
+
+/*
+ * zcache compression/decompression and related per-cpu stuff
+ */
+
+static DEFINE_PER_CPU(unsigned char *, zcache_dstmem);
+#define ZCACHE_DSTMEM_ORDER 1
+
+static void zcache_compress(struct page *from, void **out_va, unsigned *out_len)
+{
+ int ret;
+ unsigned char *dmem = __get_cpu_var(zcache_dstmem);
+ char *from_va;
+
+ BUG_ON(!irqs_disabled());
+ /* no buffer or no compressor so can't compress */
+ BUG_ON(dmem == NULL);
+ *out_len = PAGE_SIZE << ZCACHE_DSTMEM_ORDER;
+ from_va = kmap_atomic(from);
+ mb();
+ ret = zcache_comp_op(ZCACHE_COMPOP_COMPRESS, from_va, PAGE_SIZE, dmem,
+ out_len);
+ BUG_ON(ret);
+ *out_va = dmem;
+ kunmap_atomic(from_va);
+}
+
+static int zcache_comp_cpu_up(int cpu)
+{
+ struct crypto_comp *tfm;
+
+ tfm = crypto_alloc_comp(zcache_comp_name, 0, 0);
+ if (IS_ERR(tfm))
+ return NOTIFY_BAD;
+ *per_cpu_ptr(zcache_comp_pcpu_tfms, cpu) = tfm;
+ return NOTIFY_OK;
+}
+
+static void zcache_comp_cpu_down(int cpu)
+{
+ struct crypto_comp *tfm;
+
+ tfm = *per_cpu_ptr(zcache_comp_pcpu_tfms, cpu);
+ crypto_free_comp(tfm);
+ *per_cpu_ptr(zcache_comp_pcpu_tfms, cpu) = NULL;
+}
+
+static int zcache_cpu_notifier(struct notifier_block *nb,
+ unsigned long action, void *pcpu)
+{
+ int ret, i, cpu = (long)pcpu;
+ struct zcache_preload *kp;
+
+ switch (action) {
+ case CPU_UP_PREPARE:
+ ret = zcache_comp_cpu_up(cpu);
+ if (ret != NOTIFY_OK) {
+ pr_err("%s: can't allocate compressor xform\n",
+ namestr);
+ return ret;
+ }
+ per_cpu(zcache_dstmem, cpu) = (void *)__get_free_pages(
+ GFP_KERNEL | __GFP_REPEAT, ZCACHE_DSTMEM_ORDER);
+ if (ramster_enabled)
+ ramster_cpu_up(cpu);
+ break;
+ case CPU_DEAD:
+ case CPU_UP_CANCELED:
+ zcache_comp_cpu_down(cpu);
+ free_pages((unsigned long)per_cpu(zcache_dstmem, cpu),
+ ZCACHE_DSTMEM_ORDER);
+ per_cpu(zcache_dstmem, cpu) = NULL;
+ kp = &per_cpu(zcache_preloads, cpu);
+ for (i = 0; i < ARRAY_SIZE(kp->objnodes); i++) {
+ if (kp->objnodes[i])
+ kmem_cache_free(zcache_objnode_cache,
+ kp->objnodes[i]);
+ }
+ if (kp->obj) {
+ kmem_cache_free(zcache_obj_cache, kp->obj);
+ kp->obj = NULL;
+ }
+ if (ramster_enabled)
+ ramster_cpu_down(cpu);
+ break;
+ default:
+ break;
+ }
+ return NOTIFY_OK;
+}
+
+static struct notifier_block zcache_cpu_notifier_block = {
+ .notifier_call = zcache_cpu_notifier
+};
+
+/*
+ * The following code interacts with the zbud eviction and zbud
+ * zombify code to access LRU pages
+ */
+
+static struct page *zcache_evict_eph_pageframe(void)
+{
+ struct page *page;
+ unsigned int zsize = 0, zpages = 0;
+
+ page = zbud_evict_pageframe_lru(&zsize, &zpages);
+ if (page == NULL)
+ goto out;
+ zcache_eph_zbytes = atomic_long_sub_return(zsize,
+ &zcache_eph_zbytes_atomic);
+ zcache_eph_zpages = atomic_sub_return(zpages,
+ &zcache_eph_zpages_atomic);
+ zcache_evicted_eph_zpages++;
+ zcache_eph_pageframes =
+ atomic_dec_return(&zcache_eph_pageframes_atomic);
+ zcache_evicted_eph_pageframes++;
+out:
+ return page;
+}
+
+static void unswiz(struct tmem_oid oid, u32 index,
+ unsigned *type, pgoff_t *offset);
+#ifdef FRONTSWAP_HAS_UNUSE
+/*
+ * Choose an LRU persistent pageframe and attempt to "unuse" it by
+ * calling frontswap_unuse on both zpages.
+ *
+ * This is work-in-progress.
+ */
+
+static int zcache_frontswap_unuse(void)
+{
+ struct tmem_handle th[2];
+ int ret = -ENOMEM;
+ int nzbuds, unuse_ret;
+ unsigned type;
+ struct page *newpage1 = NULL, *newpage2 = NULL;
+ struct page *evictpage1 = NULL, *evictpage2 = NULL;
+ pgoff_t offset;
+
+ newpage1 = alloc_page(ZCACHE_GFP_MASK);
+ newpage2 = alloc_page(ZCACHE_GFP_MASK);
+ if (newpage1 == NULL)
+ evictpage1 = zcache_evict_eph_pageframe();
+ if (newpage2 == NULL)
+ evictpage2 = zcache_evict_eph_pageframe();
+ if (evictpage1 == NULL || evictpage2 == NULL)
+ goto free_and_out;
+ /* ok, we have two pages pre-allocated */
+ nzbuds = zbud_make_zombie_lru(&th[0], NULL, NULL, false);
+ if (nzbuds == 0) {
+ ret = -ENOENT;
+ goto free_and_out;
+ }
+ unswiz(th[0].oid, th[0].index, &type, &offset);
+ unuse_ret = frontswap_unuse(type, offset,
+ newpage1 != NULL ? newpage1 : evictpage1,
+ ZCACHE_GFP_MASK);
+ if (unuse_ret != 0)
+ goto free_and_out;
+ else if (evictpage1 != NULL)
+ zcache_unacct_page();
+ newpage1 = NULL;
+ evictpage1 = NULL;
+ if (nzbuds == 2) {
+ unswiz(th[1].oid, th[1].index, &type, &offset);
+ unuse_ret = frontswap_unuse(type, offset,
+ newpage2 != NULL ? newpage2 : evictpage2,
+ ZCACHE_GFP_MASK);
+ if (unuse_ret != 0) {
+ goto free_and_out;
+ } else if (evictpage2 != NULL) {
+ zcache_unacct_page();
+ }
+ }
+ ret = 0;
+ goto out;
+
+free_and_out:
+ if (newpage1 != NULL)
+ __free_page(newpage1);
+ if (newpage2 != NULL)
+ __free_page(newpage2);
+ if (evictpage1 != NULL)
+ zcache_free_page(evictpage1);
+ if (evictpage2 != NULL)
+ zcache_free_page(evictpage2);
+out:
+ return ret;
+}
+#endif
+
+/*
+ * When zcache is disabled ("frozen"), pools can be created and destroyed,
+ * but all puts (and thus all other operations that require memory allocation)
+ * must fail. If zcache is unfrozen, accepts puts, then frozen again,
+ * data consistency requires all puts while frozen to be converted into
+ * flushes.
+ */
+static bool zcache_freeze;
+
+/*
+ * This zcache shrinker interface reduces the number of ephemeral pageframes
+ * used by zcache to approximately the same as the total number of LRU_FILE
+ * pageframes in use.
+ */
+static int shrink_zcache_memory(struct shrinker *shrink,
+ struct shrink_control *sc)
+{
+ static bool in_progress;
+ int ret = -1;
+ int nr = sc->nr_to_scan;
+ int nr_evict = 0;
+ int nr_unuse = 0;
+ struct page *page;
+ int unuse_ret;
+
+ if (nr <= 0)
+ goto skip_evict;
+
+ /* don't allow more than one eviction thread at a time */
+ if (in_progress)
+ goto skip_evict;
+
+ in_progress = true;
+
+ /* we are going to ignore nr, and target a different value */
+ zcache_last_active_file_pageframes =
+ global_page_state(NR_LRU_BASE + LRU_ACTIVE_FILE);
+ zcache_last_inactive_file_pageframes =
+ global_page_state(NR_LRU_BASE + LRU_INACTIVE_FILE);
+ nr_evict = zcache_eph_pageframes - zcache_last_active_file_pageframes +
+ zcache_last_inactive_file_pageframes;
+ while (nr_evict-- > 0) {
+ page = zcache_evict_eph_pageframe();
+ if (page == NULL)
+ break;
+ zcache_free_page(page);
+ }
+
+ zcache_last_active_anon_pageframes =
+ global_page_state(NR_LRU_BASE + LRU_ACTIVE_ANON);
+ zcache_last_inactive_anon_pageframes =
+ global_page_state(NR_LRU_BASE + LRU_INACTIVE_ANON);
+ nr_unuse = zcache_pers_pageframes - zcache_last_active_anon_pageframes +
+ zcache_last_inactive_anon_pageframes;
+#ifdef FRONTSWAP_HAS_UNUSE
+ /* rate limit for testing */
+ if (nr_unuse > 32)
+ nr_unuse = 32;
+ while (nr_unuse-- > 0) {
+ unuse_ret = zcache_frontswap_unuse();
+ if (unuse_ret == -ENOMEM)
+ break;
+ }
+#endif
+ in_progress = false;
+
+skip_evict:
+ /* resample: has changed, but maybe not all the way yet */
+ zcache_last_active_file_pageframes =
+ global_page_state(NR_LRU_BASE + LRU_ACTIVE_FILE);
+ zcache_last_inactive_file_pageframes =
+ global_page_state(NR_LRU_BASE + LRU_INACTIVE_FILE);
+ ret = zcache_eph_pageframes - zcache_last_active_file_pageframes +
+ zcache_last_inactive_file_pageframes;
+ if (ret < 0)
+ ret = 0;
+ return ret;
+}
+
+static struct shrinker zcache_shrinker = {
+ .shrink = shrink_zcache_memory,
+ .seeks = DEFAULT_SEEKS,
+};
+
+/*
+ * zcache shims between cleancache/frontswap ops and tmem
+ */
+
+/* FIXME rename these core routines to zcache_tmemput etc? */
+int zcache_put_page(int cli_id, int pool_id, struct tmem_oid *oidp,
+ uint32_t index, void *page,
+ unsigned int size, bool raw, int ephemeral)
+{
+ struct tmem_pool *pool;
+ struct tmem_handle th;
+ int ret = -1;
+ void *pampd = NULL;
+
+ BUG_ON(!irqs_disabled());
+ pool = zcache_get_pool_by_id(cli_id, pool_id);
+ if (unlikely(pool == NULL))
+ goto out;
+ if (!zcache_freeze) {
+ ret = 0;
+ th.client_id = cli_id;
+ th.pool_id = pool_id;
+ th.oid = *oidp;
+ th.index = index;
+ pampd = zcache_pampd_create((char *)page, size, raw,
+ ephemeral, &th);
+ if (pampd == NULL) {
+ ret = -ENOMEM;
+ if (ephemeral)
+ zcache_failed_eph_puts++;
+ else
+ zcache_failed_pers_puts++;
+ } else {
+ if (ramster_enabled)
+ ramster_do_preload_flnode(pool);
+ ret = tmem_put(pool, oidp, index, 0, pampd);
+ if (ret < 0)
+ BUG();
+ }
+ zcache_put_pool(pool);
+ } else {
+ zcache_put_to_flush++;
+ if (ramster_enabled)
+ ramster_do_preload_flnode(pool);
+ if (atomic_read(&pool->obj_count) > 0)
+ /* the put fails whether the flush succeeds or not */
+ (void)tmem_flush_page(pool, oidp, index);
+ zcache_put_pool(pool);
+ }
+out:
+ return ret;
+}
+
+int zcache_get_page(int cli_id, int pool_id, struct tmem_oid *oidp,
+ uint32_t index, void *page,
+ size_t *sizep, bool raw, int get_and_free)
+{
+ struct tmem_pool *pool;
+ int ret = -1;
+ bool eph;
+
+ if (!raw) {
+ BUG_ON(irqs_disabled());
+ BUG_ON(in_softirq());
+ }
+ pool = zcache_get_pool_by_id(cli_id, pool_id);
+ eph = is_ephemeral(pool);
+ if (likely(pool != NULL)) {
+ if (atomic_read(&pool->obj_count) > 0)
+ ret = tmem_get(pool, oidp, index, (char *)(page),
+ sizep, raw, get_and_free);
+ zcache_put_pool(pool);
+ }
+ WARN_ONCE((!is_ephemeral(pool) && (ret != 0)),
+ "zcache_get fails on persistent pool, "
+ "bad things are very likely to happen soon\n");
+#ifdef RAMSTER_TESTING
+ if (ret != 0 && ret != -1 && !(ret == -EINVAL && is_ephemeral(pool)))
+ pr_err("TESTING zcache_get tmem_get returns ret=%d\n", ret);
+#endif
+ return ret;
+}
+
+int zcache_flush_page(int cli_id, int pool_id,
+ struct tmem_oid *oidp, uint32_t index)
+{
+ struct tmem_pool *pool;
+ int ret = -1;
+ unsigned long flags;
+
+ local_irq_save(flags);
+ zcache_flush_total++;
+ pool = zcache_get_pool_by_id(cli_id, pool_id);
+ if (ramster_enabled)
+ ramster_do_preload_flnode(pool);
+ if (likely(pool != NULL)) {
+ if (atomic_read(&pool->obj_count) > 0)
+ ret = tmem_flush_page(pool, oidp, index);
+ zcache_put_pool(pool);
+ }
+ if (ret >= 0)
+ zcache_flush_found++;
+ local_irq_restore(flags);
+ return ret;
+}
+
+int zcache_flush_object(int cli_id, int pool_id,
+ struct tmem_oid *oidp)
+{
+ struct tmem_pool *pool;
+ int ret = -1;
+ unsigned long flags;
+
+ local_irq_save(flags);
+ zcache_flobj_total++;
+ pool = zcache_get_pool_by_id(cli_id, pool_id);
+ if (ramster_enabled)
+ ramster_do_preload_flnode(pool);
+ if (likely(pool != NULL)) {
+ if (atomic_read(&pool->obj_count) > 0)
+ ret = tmem_flush_object(pool, oidp);
+ zcache_put_pool(pool);
+ }
+ if (ret >= 0)
+ zcache_flobj_found++;
+ local_irq_restore(flags);
+ return ret;
+}
+
+static int zcache_client_destroy_pool(int cli_id, int pool_id)
+{
+ struct tmem_pool *pool = NULL;
+ struct zcache_client *cli = NULL;
+ int ret = -1;
+
+ if (pool_id < 0)
+ goto out;
+ if (cli_id == LOCAL_CLIENT)
+ cli = &zcache_host;
+ else if ((unsigned int)cli_id < MAX_CLIENTS)
+ cli = &zcache_clients[cli_id];
+ if (cli == NULL)
+ goto out;
+ atomic_inc(&cli->refcount);
+ pool = cli->tmem_pools[pool_id];
+ if (pool == NULL)
+ goto out;
+ cli->tmem_pools[pool_id] = NULL;
+ /* wait for pool activity on other cpus to quiesce */
+ while (atomic_read(&pool->refcount) != 0)
+ ;
+ atomic_dec(&cli->refcount);
+ local_bh_disable();
+ ret = tmem_destroy_pool(pool);
+ local_bh_enable();
+ kfree(pool);
+ if (cli_id == LOCAL_CLIENT)
+ pr_info("%s: destroyed local pool id=%d\n", namestr, pool_id);
+ else
+ pr_info("%s: destroyed pool id=%d, client=%d\n",
+ namestr, pool_id, cli_id);
+out:
+ return ret;
+}
+
+int zcache_new_pool(uint16_t cli_id, uint32_t flags)
+{
+ int poolid = -1;
+ struct tmem_pool *pool;
+ struct zcache_client *cli = NULL;
+
+ if (cli_id == LOCAL_CLIENT)
+ cli = &zcache_host;
+ else if ((unsigned int)cli_id < MAX_CLIENTS)
+ cli = &zcache_clients[cli_id];
+ if (cli == NULL)
+ goto out;
+ atomic_inc(&cli->refcount);
+ pool = kmalloc(sizeof(struct tmem_pool), GFP_ATOMIC);
+ if (pool == NULL) {
+ pr_info("%s: pool creation failed: out of memory\n", namestr);
+ goto out;
+ }
+
+ for (poolid = 0; poolid < MAX_POOLS_PER_CLIENT; poolid++)
+ if (cli->tmem_pools[poolid] == NULL)
+ break;
+ if (poolid >= MAX_POOLS_PER_CLIENT) {
+ pr_info("%s: pool creation failed: max exceeded\n", namestr);
+ kfree(pool);
+ poolid = -1;
+ goto out;
+ }
+ atomic_set(&pool->refcount, 0);
+ pool->client = cli;
+ pool->pool_id = poolid;
+ tmem_new_pool(pool, flags);
+ cli->tmem_pools[poolid] = pool;
+ if (cli_id == LOCAL_CLIENT)
+ pr_info("%s: created %s local tmem pool, id=%d\n", namestr,
+ flags & TMEM_POOL_PERSIST ? "persistent" : "ephemeral",
+ poolid);
+ else
+ pr_info("%s: created %s tmem pool, id=%d, client=%d\n", namestr,
+ flags & TMEM_POOL_PERSIST ? "persistent" : "ephemeral",
+ poolid, cli_id);
+out:
+ if (cli != NULL)
+ atomic_dec(&cli->refcount);
+ return poolid;
+}
+
+static int zcache_local_new_pool(uint32_t flags)
+{
+ return zcache_new_pool(LOCAL_CLIENT, flags);
+}
+
+int zcache_autocreate_pool(int cli_id, int pool_id, bool eph)
+{
+ struct tmem_pool *pool;
+ struct zcache_client *cli = NULL;
+ uint32_t flags = eph ? 0 : TMEM_POOL_PERSIST;
+ int ret = -1;
+
+ BUG_ON(!ramster_enabled);
+ if (cli_id == LOCAL_CLIENT)
+ goto out;
+ if (pool_id >= MAX_POOLS_PER_CLIENT)
+ goto out;
+ else if ((unsigned int)cli_id < MAX_CLIENTS)
+ cli = &zcache_clients[cli_id];
+ if ((eph && disable_cleancache) || (!eph && disable_frontswap)) {
+ pr_err("zcache_autocreate_pool: pool type disabled\n");
+ goto out;
+ }
+ if (!cli->allocated) {
+ if (zcache_new_client(cli_id)) {
+ pr_err("zcache_autocreate_pool: can't create client\n");
+ goto out;
+ }
+ cli = &zcache_clients[cli_id];
+ }
+ atomic_inc(&cli->refcount);
+ pool = cli->tmem_pools[pool_id];
+ if (pool != NULL) {
+ if (pool->persistent && eph) {
+ pr_err("zcache_autocreate_pool: type mismatch\n");
+ goto out;
+ }
+ ret = 0;
+ goto out;
+ }
+ pool = kmalloc(sizeof(struct tmem_pool), GFP_KERNEL);
+ if (pool == NULL) {
+ pr_info("%s: pool creation failed: out of memory\n", namestr);
+ goto out;
+ }
+ atomic_set(&pool->refcount, 0);
+ pool->client = cli;
+ pool->pool_id = pool_id;
+ tmem_new_pool(pool, flags);
+ cli->tmem_pools[pool_id] = pool;
+ pr_info("%s: AUTOcreated %s tmem poolid=%d, for remote client=%d\n",
+ namestr, flags & TMEM_POOL_PERSIST ? "persistent" : "ephemeral",
+ pool_id, cli_id);
+ ret = 0;
+out:
+ if (cli != NULL)
+ atomic_dec(&cli->refcount);
+ return ret;
+}
+
+/**********
+ * Two kernel functionalities currently can be layered on top of tmem.
+ * These are "cleancache" which is used as a second-chance cache for clean
+ * page cache pages; and "frontswap" which is used for swap pages
+ * to avoid writes to disk. A generic "shim" is provided here for each
+ * to translate in-kernel semantics to zcache semantics.
+ */
+
+static void zcache_cleancache_put_page(int pool_id,
+ struct cleancache_filekey key,
+ pgoff_t index, struct page *page)
+{
+ u32 ind = (u32) index;
+ struct tmem_oid oid = *(struct tmem_oid *)&key;
+
+ if (!disable_cleancache_ignore_nonactive && !PageWasActive(page)) {
+ zcache_eph_nonactive_puts_ignored++;
+ return;
+ }
+ if (likely(ind == index))
+ (void)zcache_put_page(LOCAL_CLIENT, pool_id, &oid, index,
+ page, PAGE_SIZE, false, 1);
+}
+
+static int zcache_cleancache_get_page(int pool_id,
+ struct cleancache_filekey key,
+ pgoff_t index, struct page *page)
+{
+ u32 ind = (u32) index;
+ struct tmem_oid oid = *(struct tmem_oid *)&key;
+ size_t size;
+ int ret = -1;
+
+ if (likely(ind == index)) {
+ ret = zcache_get_page(LOCAL_CLIENT, pool_id, &oid, index,
+ page, &size, false, 0);
+ BUG_ON(ret >= 0 && size != PAGE_SIZE);
+ if (ret == 0)
+ SetPageWasActive(page);
+ }
+ return ret;
+}
+
+static void zcache_cleancache_flush_page(int pool_id,
+ struct cleancache_filekey key,
+ pgoff_t index)
+{
+ u32 ind = (u32) index;
+ struct tmem_oid oid = *(struct tmem_oid *)&key;
+
+ if (likely(ind == index))
+ (void)zcache_flush_page(LOCAL_CLIENT, pool_id, &oid, ind);
+}
+
+static void zcache_cleancache_flush_inode(int pool_id,
+ struct cleancache_filekey key)
+{
+ struct tmem_oid oid = *(struct tmem_oid *)&key;
+
+ (void)zcache_flush_object(LOCAL_CLIENT, pool_id, &oid);
+}
+
+static void zcache_cleancache_flush_fs(int pool_id)
+{
+ if (pool_id >= 0)
+ (void)zcache_client_destroy_pool(LOCAL_CLIENT, pool_id);
+}
+
+static int zcache_cleancache_init_fs(size_t pagesize)
+{
+ BUG_ON(sizeof(struct cleancache_filekey) !=
+ sizeof(struct tmem_oid));
+ BUG_ON(pagesize != PAGE_SIZE);
+ return zcache_local_new_pool(0);
+}
+
+static int zcache_cleancache_init_shared_fs(char *uuid, size_t pagesize)
+{
+ /* shared pools are unsupported and map to private */
+ BUG_ON(sizeof(struct cleancache_filekey) !=
+ sizeof(struct tmem_oid));
+ BUG_ON(pagesize != PAGE_SIZE);
+ return zcache_local_new_pool(0);
+}
+
+static struct cleancache_ops zcache_cleancache_ops = {
+ .put_page = zcache_cleancache_put_page,
+ .get_page = zcache_cleancache_get_page,
+ .invalidate_page = zcache_cleancache_flush_page,
+ .invalidate_inode = zcache_cleancache_flush_inode,
+ .invalidate_fs = zcache_cleancache_flush_fs,
+ .init_shared_fs = zcache_cleancache_init_shared_fs,
+ .init_fs = zcache_cleancache_init_fs
+};
+
+struct cleancache_ops zcache_cleancache_register_ops(void)
+{
+ struct cleancache_ops old_ops =
+ cleancache_register_ops(&zcache_cleancache_ops);
+
+ return old_ops;
+}
+
+/* a single tmem poolid is used for all frontswap "types" (swapfiles) */
+static int zcache_frontswap_poolid __read_mostly = -1;
+
+/*
+ * Swizzling increases objects per swaptype, increasing tmem concurrency
+ * for heavy swaploads. Later, larger nr_cpus -> larger SWIZ_BITS
+ * Setting SWIZ_BITS to 27 basically reconstructs the swap entry from
+ * frontswap_get_page(), but has side-effects. Hence using 8.
+ */
+#define SWIZ_BITS 8
+#define SWIZ_MASK ((1 << SWIZ_BITS) - 1)
+#define _oswiz(_type, _ind) ((_type << SWIZ_BITS) | (_ind & SWIZ_MASK))
+#define iswiz(_ind) (_ind >> SWIZ_BITS)
+
+static inline struct tmem_oid oswiz(unsigned type, u32 ind)
+{
+ struct tmem_oid oid = { .oid = { 0 } };
+ oid.oid[0] = _oswiz(type, ind);
+ return oid;
+}
+
+static void unswiz(struct tmem_oid oid, u32 index,
+ unsigned *type, pgoff_t *offset)
+{
+ *type = (unsigned)(oid.oid[0] >> SWIZ_BITS);
+ *offset = (pgoff_t)((index << SWIZ_BITS) |
+ (oid.oid[0] & SWIZ_MASK));
+}
+
+static int zcache_frontswap_put_page(unsigned type, pgoff_t offset,
+ struct page *page)
+{
+ u64 ind64 = (u64)offset;
+ u32 ind = (u32)offset;
+ struct tmem_oid oid = oswiz(type, ind);
+ int ret = -1;
+ unsigned long flags;
+ int unuse_ret;
+
+ BUG_ON(!PageLocked(page));
+ if (!disable_frontswap_ignore_nonactive && !PageWasActive(page)) {
+ zcache_pers_nonactive_puts_ignored++;
+ ret = -ERANGE;
+ goto out;
+ }
+ if (likely(ind64 == ind)) {
+ local_irq_save(flags);
+ ret = zcache_put_page(LOCAL_CLIENT, zcache_frontswap_poolid,
+ &oid, iswiz(ind),
+ page, PAGE_SIZE, false, 0);
+ local_irq_restore(flags);
+ }
+out:
+ return ret;
+}
+
+/* returns 0 if the page was successfully gotten from frontswap, -1 if
+ * was not present (should never happen!) */
+static int zcache_frontswap_get_page(unsigned type, pgoff_t offset,
+ struct page *page)
+{
+ u64 ind64 = (u64)offset;
+ u32 ind = (u32)offset;
+ struct tmem_oid oid = oswiz(type, ind);
+ size_t size;
+ int ret = -1, get_and_free;
+
+ if (frontswap_has_exclusive_gets)
+ get_and_free = 1;
+ else
+ get_and_free = -1;
+ BUG_ON(!PageLocked(page));
+ if (likely(ind64 == ind)) {
+ ret = zcache_get_page(LOCAL_CLIENT, zcache_frontswap_poolid,
+ &oid, iswiz(ind),
+ page, &size, false, get_and_free);
+ BUG_ON(ret >= 0 && size != PAGE_SIZE);
+ }
+ return ret;
+}
+
+/* flush a single page from frontswap */
+static void zcache_frontswap_flush_page(unsigned type, pgoff_t offset)
+{
+ u64 ind64 = (u64)offset;
+ u32 ind = (u32)offset;
+ struct tmem_oid oid = oswiz(type, ind);
+
+ if (likely(ind64 == ind))
+ (void)zcache_flush_page(LOCAL_CLIENT, zcache_frontswap_poolid,
+ &oid, iswiz(ind));
+}
+
+/* flush all pages from the passed swaptype */
+static void zcache_frontswap_flush_area(unsigned type)
+{
+ struct tmem_oid oid;
+ int ind;
+
+ for (ind = SWIZ_MASK; ind >= 0; ind--) {
+ oid = oswiz(type, ind);
+ (void)zcache_flush_object(LOCAL_CLIENT,
+ zcache_frontswap_poolid, &oid);
+ }
+}
+
+static void zcache_frontswap_init(unsigned ignored)
+{
+ /* a single tmem poolid is used for all frontswap "types" (swapfiles) */
+ if (zcache_frontswap_poolid < 0)
+ zcache_frontswap_poolid =
+ zcache_local_new_pool(TMEM_POOL_PERSIST);
+}
+
+static struct frontswap_ops zcache_frontswap_ops = {
+ .store = zcache_frontswap_put_page,
+ .load = zcache_frontswap_get_page,
+ .invalidate_page = zcache_frontswap_flush_page,
+ .invalidate_area = zcache_frontswap_flush_area,
+ .init = zcache_frontswap_init
+};
+
+struct frontswap_ops zcache_frontswap_register_ops(void)
+{
+ struct frontswap_ops old_ops =
+ frontswap_register_ops(&zcache_frontswap_ops);
+
+ return old_ops;
+}
+
+/*
+ * zcache initialization
+ * NOTE FOR NOW zcache or ramster MUST BE PROVIDED AS A KERNEL BOOT PARAMETER
+ * OR NOTHING HAPPENS!
+ */
+
+static int __init enable_zcache(char *s)
+{
+ zcache_enabled = 1;
+ return 1;
+}
+__setup("zcache", enable_zcache);
+
+static int __init enable_ramster(char *s)
+{
+ zcache_enabled = 1;
+#ifdef CONFIG_RAMSTER
+ ramster_enabled = 1;
+#endif
+ return 1;
+}
+__setup("ramster", enable_ramster);
+
+/* allow independent dynamic disabling of cleancache and frontswap */
+
+static int __init no_cleancache(char *s)
+{
+ disable_cleancache = 1;
+ return 1;
+}
+
+__setup("nocleancache", no_cleancache);
+
+static int __init no_frontswap(char *s)
+{
+ disable_frontswap = 1;
+ return 1;
+}
+
+__setup("nofrontswap", no_frontswap);
+
+static int __init no_frontswap_exclusive_gets(char *s)
+{
+ frontswap_has_exclusive_gets = false;
+ return 1;
+}
+
+__setup("nofrontswapexclusivegets", no_frontswap_exclusive_gets);
+
+static int __init no_frontswap_ignore_nonactive(char *s)
+{
+ disable_frontswap_ignore_nonactive = 1;
+ return 1;
+}
+
+__setup("nofrontswapignorenonactive", no_frontswap_ignore_nonactive);
+
+static int __init no_cleancache_ignore_nonactive(char *s)
+{
+ disable_cleancache_ignore_nonactive = 1;
+ return 1;
+}
+
+__setup("nocleancacheignorenonactive", no_cleancache_ignore_nonactive);
+
+static int __init enable_zcache_compressor(char *s)
+{
+ strncpy(zcache_comp_name, s, ZCACHE_COMP_NAME_SZ);
+ zcache_enabled = 1;
+ return 1;
+}
+__setup("zcache=", enable_zcache_compressor);
+
+
+static int __init zcache_comp_init(void)
+{
+ int ret = 0;
+
+ /* check crypto algorithm */
+ if (*zcache_comp_name != '\0') {
+ ret = crypto_has_comp(zcache_comp_name, 0, 0);
+ if (!ret)
+ pr_info("zcache: %s not supported\n",
+ zcache_comp_name);
+ }
+ if (!ret)
+ strcpy(zcache_comp_name, "lzo");
+ ret = crypto_has_comp(zcache_comp_name, 0, 0);
+ if (!ret) {
+ ret = 1;
+ goto out;
+ }
+ pr_info("zcache: using %s compressor\n", zcache_comp_name);
+
+ /* alloc percpu transforms */
+ ret = 0;
+ zcache_comp_pcpu_tfms = alloc_percpu(struct crypto_comp *);
+ if (!zcache_comp_pcpu_tfms)
+ ret = 1;
+out:
+ return ret;
+}
+
+static int __init zcache_init(void)
+{
+ int ret = 0;
+
+ if (ramster_enabled) {
+ namestr = "ramster";
+ ramster_register_pamops(&zcache_pamops);
+ }
+#ifdef CONFIG_DEBUG_FS
+ zcache_debugfs_init();
+#endif
+ if (zcache_enabled) {
+ unsigned int cpu;
+
+ tmem_register_hostops(&zcache_hostops);
+ tmem_register_pamops(&zcache_pamops);
+ ret = register_cpu_notifier(&zcache_cpu_notifier_block);
+ if (ret) {
+ pr_err("%s: can't register cpu notifier\n", namestr);
+ goto out;
+ }
+ ret = zcache_comp_init();
+ if (ret) {
+ pr_err("%s: compressor initialization failed\n",
+ namestr);
+ goto out;
+ }
+ for_each_online_cpu(cpu) {
+ void *pcpu = (void *)(long)cpu;
+ zcache_cpu_notifier(&zcache_cpu_notifier_block,
+ CPU_UP_PREPARE, pcpu);
+ }
+ }
+ zcache_objnode_cache = kmem_cache_create("zcache_objnode",
+ sizeof(struct tmem_objnode), 0, 0, NULL);
+ zcache_obj_cache = kmem_cache_create("zcache_obj",
+ sizeof(struct tmem_obj), 0, 0, NULL);
+ ret = zcache_new_client(LOCAL_CLIENT);
+ if (ret) {
+ pr_err("%s: can't create client\n", namestr);
+ goto out;
+ }
+ zbud_init();
+ if (zcache_enabled && !disable_cleancache) {
+ struct cleancache_ops old_ops;
+
+ register_shrinker(&zcache_shrinker);
+ old_ops = zcache_cleancache_register_ops();
+ pr_info("%s: cleancache enabled using kernel transcendent "
+ "memory and compression buddies\n", namestr);
+#ifdef ZCACHE_DEBUG
+ pr_info("%s: cleancache: ignorenonactive = %d\n",
+ namestr, !disable_cleancache_ignore_nonactive);
+#endif
+ if (old_ops.init_fs != NULL)
+ pr_warn("%s: cleancache_ops overridden\n", namestr);
+ }
+ if (zcache_enabled && !disable_frontswap) {
+ struct frontswap_ops old_ops;
+
+ old_ops = zcache_frontswap_register_ops();
+ if (frontswap_has_exclusive_gets)
+ frontswap_tmem_exclusive_gets(true);
+ pr_info("%s: frontswap enabled using kernel transcendent "
+ "memory and compression buddies\n", namestr);
+#ifdef ZCACHE_DEBUG
+ pr_info("%s: frontswap: excl gets = %d active only = %d\n",
+ namestr, frontswap_has_exclusive_gets,
+ !disable_frontswap_ignore_nonactive);
+#endif
+ if (old_ops.init != NULL)
+ pr_warn("%s: frontswap_ops overridden\n", namestr);
+ }
+ if (ramster_enabled)
+ ramster_init(!disable_cleancache, !disable_frontswap,
+ frontswap_has_exclusive_gets);
+out:
+ return ret;
+}
+
+late_initcall(zcache_init);
--- /dev/null
+
+/*
+ * zcache.h
+ *
+ * Copyright (c) 2012, Dan Magenheimer, Oracle Corp.
+ */
+
+#ifndef _ZCACHE_H_
+#define _ZCACHE_H_
+
+struct zcache_preload {
+ struct tmem_obj *obj;
+ struct tmem_objnode *objnodes[OBJNODE_TREE_MAX_PATH];
+};
+
+struct tmem_pool;
+
+#define MAX_POOLS_PER_CLIENT 16
+
+#define MAX_CLIENTS 16
+#define LOCAL_CLIENT ((uint16_t)-1)
+
+struct zcache_client {
+ struct tmem_pool *tmem_pools[MAX_POOLS_PER_CLIENT];
+ bool allocated;
+ atomic_t refcount;
+};
+
+extern struct tmem_pool *zcache_get_pool_by_id(uint16_t cli_id,
+ uint16_t poolid);
+extern void zcache_put_pool(struct tmem_pool *pool);
+
+extern int zcache_put_page(int, int, struct tmem_oid *,
+ uint32_t, void *,
+ unsigned int, bool, int);
+extern int zcache_get_page(int, int, struct tmem_oid *, uint32_t,
+ void *, size_t *, bool, int);
+extern int zcache_flush_page(int, int, struct tmem_oid *, uint32_t);
+extern int zcache_flush_object(int, int, struct tmem_oid *);
+extern void zcache_decompress_to_page(char *, unsigned int, struct page *);
+
+#ifdef CONFIG_RAMSTER
+extern void *zcache_pampd_create(char *, unsigned int, bool, int,
+ struct tmem_handle *);
+extern int zcache_autocreate_pool(int, int, bool);
+#endif
+
+#define MAX_POOLS_PER_CLIENT 16
+
+#define MAX_CLIENTS 16
+#define LOCAL_CLIENT ((uint16_t)-1)
+
+#endif /* _ZCACHE_H_ */
projects / GitHub / LineageOS / android_kernel_motorola_exynos9610.git / commitdiff