The disksize file is read-write and specifies the disk size
which represents the limit on the *uncompressed* worth of data
that can be stored in this disk.
+ Unit: bytes
What: /sys/block/zram<id>/initstate
Date: August 2010
Contact: Nitin Gupta <ngupta@vflare.org>
Description:
- The disksize file is read-only and shows the initialization
+ The initstate file is read-only and shows the initialization
state of the device.
What: /sys/block/zram<id>/reset
Date: August 2010
Contact: Nitin Gupta <ngupta@vflare.org>
Description:
- The disksize file is write-only and allows resetting the
- device. The reset operation frees all the memory assocaited
+ The reset file is write-only and allows resetting the
+ device. The reset operation frees all the memory associated
with this device.
What: /sys/block/zram<id>/num_reads
The invalid_io file is read-only and specifies the number of
non-page-size-aligned I/O requests issued to this device.
-What: /sys/block/zram<id>/notify_free
-Date: August 2010
-Contact: Nitin Gupta <ngupta@vflare.org>
+What: /sys/block/zram<id>/failed_reads
+Date: February 2014
+Contact: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
+Description:
+ The failed_reads file is read-only and specifies the number of
+ failed reads happened on this device.
+
+What: /sys/block/zram<id>/failed_writes
+Date: February 2014
+Contact: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Description:
- The notify_free file is read-only and specifies the number of
- swap slot free notifications received by this device. These
- notifications are send to a swap block device when a swap slot
- is freed. This statistic is applicable only when this disk is
- being used as a swap disk.
+ The failed_writes file is read-only and specifies the number of
+ failed writes happened on this device.
-What: /sys/block/zram<id>/discard
+What: /sys/block/zram<id>/max_comp_streams
+Date: February 2014
+Contact: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
+Description:
+ The max_comp_streams file is read-write and specifies the
+ number of backend's zcomp_strm compression streams (number of
+ concurrent compress operations).
+
+What: /sys/block/zram<id>/comp_algorithm
+Date: February 2014
+Contact: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
+Description:
+ The comp_algorithm file is read-write and lets to show
+ available and selected compression algorithms, change
+ compression algorithm selection.
+
+What: /sys/block/zram<id>/notify_free
Date: August 2010
Contact: Nitin Gupta <ngupta@vflare.org>
Description:
- The discard file is read-only and specifies the number of
- discard requests received by this device. These requests
- provide information to block device regarding blocks which are
- no longer used by filesystem.
+ The notify_free file is read-only. Depending on device usage
+ scenario it may account a) the number of pages freed because
+ of swap slot free notifications or b) the number of pages freed
+ because of REQ_DISCARD requests sent by bio. The former ones
+ are sent to a swap block device when a swap slot is freed, which
+ implies that this disk is being used as a swap disk. The latter
+ ones are sent by filesystem mounted with discard option,
+ whenever some data blocks are getting discarded.
What: /sys/block/zram<id>/zero_pages
Date: August 2010
efficiency can be calculated using compr_data_size and this
statistic.
Unit: bytes
+
+What: /sys/block/zram<id>/mem_used_max
+Date: August 2014
+Contact: Minchan Kim <minchan@kernel.org>
+Description:
+ The mem_used_max file is read/write and specifies the amount
+ of maximum memory zram have consumed to store compressed data.
+ For resetting the value, you should write "0". Otherwise,
+ you could see -EINVAL.
+ Unit: bytes
+
+What: /sys/block/zram<id>/mem_limit
+Date: August 2014
+Contact: Minchan Kim <minchan@kernel.org>
+Description:
+ The mem_limit file is read/write and specifies the maximum
+ amount of memory ZRAM can use to store the compressed data. The
+ limit could be changed in run time and "0" means disable the
+ limit. No limit is the initial state. Unit: bytes
+
+What: /sys/block/zram<id>/compact
+Date: August 2015
+Contact: Minchan Kim <minchan@kernel.org>
+Description:
+ The compact file is write-only and trigger compaction for
+ allocator zrm uses. The allocator moves some objects so that
+ it could free fragment space.
+
+What: /sys/block/zram<id>/io_stat
+Date: August 2015
+Contact: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
+Description:
+ The io_stat file is read-only and accumulates device's I/O
+ statistics not accounted by block layer. For example,
+ failed_reads, failed_writes, etc. File format is similar to
+ block layer statistics file format.
+
+What: /sys/block/zram<id>/mm_stat
+Date: August 2015
+Contact: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
+Description:
+ The mm_stat file is read-only and represents device's mm
+ statistics (orig_data_size, compr_data_size, etc.) in a format
+ similar to block layer statistics file format.
--- /dev/null
+zram: Compressed RAM based block devices
+----------------------------------------
+
+* Introduction
+
+The zram module creates RAM based block devices named /dev/zram<id>
+(<id> = 0, 1, ...). Pages written to these disks are compressed and stored
+in memory itself. These disks allow very fast I/O and compression provides
+good amounts of memory savings. Some of the usecases include /tmp storage,
+use as swap disks, various caches under /var and maybe many more :)
+
+Statistics for individual zram devices are exported through sysfs nodes at
+/sys/block/zram<id>/
+
+* Usage
+
+Following shows a typical sequence of steps for using zram.
+
+1) Load Module:
+ modprobe zram num_devices=4
+ This creates 4 devices: /dev/zram{0,1,2,3}
+ (num_devices parameter is optional. Default: 1)
+
+2) Set max number of compression streams
+ Compression backend may use up to max_comp_streams compression streams,
+ thus allowing up to max_comp_streams concurrent compression operations.
+ By default, compression backend uses single compression stream.
+
+ Examples:
+ #show max compression streams number
+ cat /sys/block/zram0/max_comp_streams
+
+ #set max compression streams number to 3
+ echo 3 > /sys/block/zram0/max_comp_streams
+
+Note:
+In order to enable compression backend's multi stream support max_comp_streams
+must be initially set to desired concurrency level before ZRAM device
+initialisation. Once the device initialised as a single stream compression
+backend (max_comp_streams equals to 1), you will see error if you try to change
+the value of max_comp_streams because single stream compression backend
+implemented as a special case by lock overhead issue and does not support
+dynamic max_comp_streams. Only multi stream backend supports dynamic
+max_comp_streams adjustment.
+
+3) Select compression algorithm
+ Using comp_algorithm device attribute one can see available and
+ currently selected (shown in square brackets) compression algortithms,
+ change selected compression algorithm (once the device is initialised
+ there is no way to change compression algorithm).
+
+ Examples:
+ #show supported compression algorithms
+ cat /sys/block/zram0/comp_algorithm
+ lzo [lz4]
+
+ #select lzo compression algorithm
+ echo lzo > /sys/block/zram0/comp_algorithm
+
+4) Set Disksize
+ Set disk size by writing the value to sysfs node 'disksize'.
+ The value can be either in bytes or you can use mem suffixes.
+ Examples:
+ # Initialize /dev/zram0 with 50MB disksize
+ echo $((50*1024*1024)) > /sys/block/zram0/disksize
+
+ # Using mem suffixes
+ echo 256K > /sys/block/zram0/disksize
+ echo 512M > /sys/block/zram0/disksize
+ echo 1G > /sys/block/zram0/disksize
+
+Note:
+There is little point creating a zram of greater than twice the size of memory
+since we expect a 2:1 compression ratio. Note that zram uses about 0.1% of the
+size of the disk when not in use so a huge zram is wasteful.
+
+5) Set memory limit: Optional
+ Set memory limit by writing the value to sysfs node 'mem_limit'.
+ The value can be either in bytes or you can use mem suffixes.
+ In addition, you could change the value in runtime.
+ Examples:
+ # limit /dev/zram0 with 50MB memory
+ echo $((50*1024*1024)) > /sys/block/zram0/mem_limit
+
+ # Using mem suffixes
+ echo 256K > /sys/block/zram0/mem_limit
+ echo 512M > /sys/block/zram0/mem_limit
+ echo 1G > /sys/block/zram0/mem_limit
+
+ # To disable memory limit
+ echo 0 > /sys/block/zram0/mem_limit
+
+6) Activate:
+ mkswap /dev/zram0
+ swapon /dev/zram0
+
+ mkfs.ext4 /dev/zram1
+ mount /dev/zram1 /tmp
+
+7) Stats:
+Per-device statistics are exported as various nodes under /sys/block/zram<id>/
+
+A brief description of exported device attritbutes. For more details please
+read Documentation/ABI/testing/sysfs-block-zram.
+
+Name access description
+---- ------ -----------
+disksize RW show and set the device's disk size
+initstate RO shows the initialization state of the device
+reset WO trigger device reset
+num_reads RO the number of reads
+failed_reads RO the number of failed reads
+num_write RO the number of writes
+failed_writes RO the number of failed writes
+invalid_io RO the number of non-page-size-aligned I/O requests
+max_comp_streams RW the number of possible concurrent compress operations
+comp_algorithm RW show and change the compression algorithm
+notify_free RO the number of notifications to free pages (either
+ slot free notifications or REQ_DISCARD requests)
+zero_pages RO the number of zero filled pages written to this disk
+orig_data_size RO uncompressed size of data stored in this disk
+compr_data_size RO compressed size of data stored in this disk
+mem_used_total RO the amount of memory allocated for this disk
+mem_used_max RW the maximum amount memory zram have consumed to
+ store compressed data
+mem_limit RW the maximum amount of memory ZRAM can use to store
+ the compressed data
+num_migrated RO the number of objects migrated migrated by compaction
+
+
+WARNING
+=======
+per-stat sysfs attributes are considered to be deprecated.
+The basic strategy is:
+-- the existing RW nodes will be downgraded to WO nodes (in linux 4.11)
+-- deprecated RO sysfs nodes will eventually be removed (in linux 4.11)
+
+The list of deprecated attributes can be found here:
+Documentation/ABI/obsolete/sysfs-block-zram
+
+Basically, every attribute that has its own read accessible sysfs node
+(e.g. num_reads) *AND* is accessible via one of the stat files (zram<id>/stat
+or zram<id>/io_stat or zram<id>/mm_stat) is considered to be deprecated.
+
+User space is advised to use the following files to read the device statistics.
+
+File /sys/block/zram<id>/stat
+
+Represents block layer statistics. Read Documentation/block/stat.txt for
+details.
+
+File /sys/block/zram<id>/io_stat
+
+The stat file represents device's I/O statistics not accounted by block
+layer and, thus, not available in zram<id>/stat file. It consists of a
+single line of text and contains the following stats separated by
+whitespace:
+ failed_reads
+ failed_writes
+ invalid_io
+ notify_free
+
+File /sys/block/zram<id>/mm_stat
+
+The stat file represents device's mm statistics. It consists of a single
+line of text and contains the following stats separated by whitespace:
+ orig_data_size
+ compr_data_size
+ mem_used_total
+ mem_limit
+ mem_used_max
+ zero_pages
+ num_migrated
+
+8) Deactivate:
+ swapoff /dev/zram0
+ umount /dev/zram1
+
+9) Reset:
+ Write any positive value to 'reset' sysfs node
+ echo 1 > /sys/block/zram0/reset
+ echo 1 > /sys/block/zram1/reset
+
+ This frees all the memory allocated for the given device and
+ resets the disksize to zero. You must set the disksize again
+ before reusing the device.
+
+Nitin Gupta
+ngupta@vflare.org
source "drivers/block/mtip32xx/Kconfig"
+source "drivers/block/zram/Kconfig"
+
config BLK_CPQ_DA
tristate "Compaq SMART2 support"
depends on PCI && VIRT_TO_BUS
obj-$(CONFIG_BLK_DEV_PCIESSD_MTIP32XX) += mtip32xx/
obj-$(CONFIG_BLK_DEV_RSXX) += rsxx/
+obj-$(CONFIG_ZRAM) += zram/
nvme-y := nvme-core.o nvme-scsi.o
swim_mod-y := swim.o swim_asm.o
--- /dev/null
+config ZRAM
+ tristate "Compressed RAM block device support"
+ depends on BLOCK && SYSFS && ZSMALLOC
+ select LZO_COMPRESS
+ select LZO_DECOMPRESS
+ default n
+ help
+ Creates virtual block devices called /dev/zramX (X = 0, 1, ...).
+ Pages written to these disks are compressed and stored in memory
+ itself. These disks allow very fast I/O and compression provides
+ good amounts of memory savings.
+
+ It has several use cases, for example: /tmp storage, use as swap
+ disks and maybe many more.
+
+ See zram.txt for more information.
+
+config ZRAM_LZ4_COMPRESS
+ bool "Enable LZ4 algorithm support"
+ depends on ZRAM
+ select LZ4_COMPRESS
+ select LZ4_DECOMPRESS
+ default n
+ help
+ This option enables LZ4 compression algorithm support. Compression
+ algorithm can be changed using `comp_algorithm' device attribute.
+
+config ZRAM_DEBUG
+ bool "Compressed RAM block device debug support"
+ depends on ZRAM
+ default n
+ help
+ This option adds additional debugging code to the compressed
+ RAM block device driver.
--- /dev/null
+zram-y := zcomp_lzo.o zcomp.o zram_drv.o
+
+zram-$(CONFIG_ZRAM_LZ4_COMPRESS) += zcomp_lz4.o
+
+obj-$(CONFIG_ZRAM) += zram.o
--- /dev/null
+/*
+ * Copyright (C) 2014 Sergey Senozhatsky.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/kernel.h>
+#include <linux/string.h>
+#include <linux/err.h>
+#include <linux/slab.h>
+#include <linux/wait.h>
+#include <linux/sched.h>
+
+#include "zcomp.h"
+#include "zcomp_lzo.h"
+#ifdef CONFIG_ZRAM_LZ4_COMPRESS
+#include "zcomp_lz4.h"
+#endif
+
+/*
+ * single zcomp_strm backend
+ */
+struct zcomp_strm_single {
+ struct mutex strm_lock;
+ struct zcomp_strm *zstrm;
+};
+
+/*
+ * multi zcomp_strm backend
+ */
+struct zcomp_strm_multi {
+ /* protect strm list */
+ spinlock_t strm_lock;
+ /* max possible number of zstrm streams */
+ int max_strm;
+ /* number of available zstrm streams */
+ int avail_strm;
+ /* list of available strms */
+ struct list_head idle_strm;
+ wait_queue_head_t strm_wait;
+};
+
+static struct zcomp_backend *backends[] = {
+ &zcomp_lzo,
+#ifdef CONFIG_ZRAM_LZ4_COMPRESS
+ &zcomp_lz4,
+#endif
+ NULL
+};
+
+static struct zcomp_backend *find_backend(const char *compress)
+{
+ int i = 0;
+ while (backends[i]) {
+ if (sysfs_streq(compress, backends[i]->name))
+ break;
+ i++;
+ }
+ return backends[i];
+}
+
+static void zcomp_strm_free(struct zcomp *comp, struct zcomp_strm *zstrm)
+{
+ if (zstrm->private)
+ comp->backend->destroy(zstrm->private);
+ free_pages((unsigned long)zstrm->buffer, 1);
+ kfree(zstrm);
+}
+
+/*
+ * allocate new zcomp_strm structure with ->private initialized by
+ * backend, return NULL on error
+ */
+static struct zcomp_strm *zcomp_strm_alloc(struct zcomp *comp)
+{
+ struct zcomp_strm *zstrm = kmalloc(sizeof(*zstrm), GFP_NOIO);
+ if (!zstrm)
+ return NULL;
+
+ zstrm->private = comp->backend->create();
+ /*
+ * allocate 2 pages. 1 for compressed data, plus 1 extra for the
+ * case when compressed size is larger than the original one
+ */
+ zstrm->buffer = (void *)__get_free_pages(GFP_NOIO | __GFP_ZERO, 1);
+ if (!zstrm->private || !zstrm->buffer) {
+ zcomp_strm_free(comp, zstrm);
+ zstrm = NULL;
+ }
+ return zstrm;
+}
+
+/*
+ * get idle zcomp_strm or wait until other process release
+ * (zcomp_strm_release()) one for us
+ */
+static struct zcomp_strm *zcomp_strm_multi_find(struct zcomp *comp)
+{
+ struct zcomp_strm_multi *zs = comp->stream;
+ struct zcomp_strm *zstrm;
+
+ while (1) {
+ spin_lock(&zs->strm_lock);
+ if (!list_empty(&zs->idle_strm)) {
+ zstrm = list_entry(zs->idle_strm.next,
+ struct zcomp_strm, list);
+ list_del(&zstrm->list);
+ spin_unlock(&zs->strm_lock);
+ return zstrm;
+ }
+ /* zstrm streams limit reached, wait for idle stream */
+ if (zs->avail_strm >= zs->max_strm) {
+ spin_unlock(&zs->strm_lock);
+ wait_event(zs->strm_wait, !list_empty(&zs->idle_strm));
+ continue;
+ }
+ /* allocate new zstrm stream */
+ zs->avail_strm++;
+ spin_unlock(&zs->strm_lock);
+
+ zstrm = zcomp_strm_alloc(comp);
+ if (!zstrm) {
+ spin_lock(&zs->strm_lock);
+ zs->avail_strm--;
+ spin_unlock(&zs->strm_lock);
+ wait_event(zs->strm_wait, !list_empty(&zs->idle_strm));
+ continue;
+ }
+ break;
+ }
+ return zstrm;
+}
+
+/* add stream back to idle list and wake up waiter or free the stream */
+static void zcomp_strm_multi_release(struct zcomp *comp, struct zcomp_strm *zstrm)
+{
+ struct zcomp_strm_multi *zs = comp->stream;
+
+ spin_lock(&zs->strm_lock);
+ if (zs->avail_strm <= zs->max_strm) {
+ list_add(&zstrm->list, &zs->idle_strm);
+ spin_unlock(&zs->strm_lock);
+ wake_up(&zs->strm_wait);
+ return;
+ }
+
+ zs->avail_strm--;
+ spin_unlock(&zs->strm_lock);
+ zcomp_strm_free(comp, zstrm);
+}
+
+/* change max_strm limit */
+static bool zcomp_strm_multi_set_max_streams(struct zcomp *comp, int num_strm)
+{
+ struct zcomp_strm_multi *zs = comp->stream;
+ struct zcomp_strm *zstrm;
+
+ spin_lock(&zs->strm_lock);
+ zs->max_strm = num_strm;
+ /*
+ * if user has lowered the limit and there are idle streams,
+ * immediately free as much streams (and memory) as we can.
+ */
+ while (zs->avail_strm > num_strm && !list_empty(&zs->idle_strm)) {
+ zstrm = list_entry(zs->idle_strm.next,
+ struct zcomp_strm, list);
+ list_del(&zstrm->list);
+ zcomp_strm_free(comp, zstrm);
+ zs->avail_strm--;
+ }
+ spin_unlock(&zs->strm_lock);
+ return true;
+}
+
+static void zcomp_strm_multi_destroy(struct zcomp *comp)
+{
+ struct zcomp_strm_multi *zs = comp->stream;
+ struct zcomp_strm *zstrm;
+
+ while (!list_empty(&zs->idle_strm)) {
+ zstrm = list_entry(zs->idle_strm.next,
+ struct zcomp_strm, list);
+ list_del(&zstrm->list);
+ zcomp_strm_free(comp, zstrm);
+ }
+ kfree(zs);
+}
+
+static int zcomp_strm_multi_create(struct zcomp *comp, int max_strm)
+{
+ struct zcomp_strm *zstrm;
+ struct zcomp_strm_multi *zs;
+
+ comp->destroy = zcomp_strm_multi_destroy;
+ comp->strm_find = zcomp_strm_multi_find;
+ comp->strm_release = zcomp_strm_multi_release;
+ comp->set_max_streams = zcomp_strm_multi_set_max_streams;
+ zs = kmalloc(sizeof(struct zcomp_strm_multi), GFP_KERNEL);
+ if (!zs)
+ return -ENOMEM;
+
+ comp->stream = zs;
+ spin_lock_init(&zs->strm_lock);
+ INIT_LIST_HEAD(&zs->idle_strm);
+ init_waitqueue_head(&zs->strm_wait);
+ zs->max_strm = max_strm;
+ zs->avail_strm = 1;
+
+ zstrm = zcomp_strm_alloc(comp);
+ if (!zstrm) {
+ kfree(zs);
+ return -ENOMEM;
+ }
+ list_add(&zstrm->list, &zs->idle_strm);
+ return 0;
+}
+
+static struct zcomp_strm *zcomp_strm_single_find(struct zcomp *comp)
+{
+ struct zcomp_strm_single *zs = comp->stream;
+ mutex_lock(&zs->strm_lock);
+ return zs->zstrm;
+}
+
+static void zcomp_strm_single_release(struct zcomp *comp,
+ struct zcomp_strm *zstrm)
+{
+ struct zcomp_strm_single *zs = comp->stream;
+ mutex_unlock(&zs->strm_lock);
+}
+
+static bool zcomp_strm_single_set_max_streams(struct zcomp *comp, int num_strm)
+{
+ /* zcomp_strm_single support only max_comp_streams == 1 */
+ return false;
+}
+
+static void zcomp_strm_single_destroy(struct zcomp *comp)
+{
+ struct zcomp_strm_single *zs = comp->stream;
+ zcomp_strm_free(comp, zs->zstrm);
+ kfree(zs);
+}
+
+static int zcomp_strm_single_create(struct zcomp *comp)
+{
+ struct zcomp_strm_single *zs;
+
+ comp->destroy = zcomp_strm_single_destroy;
+ comp->strm_find = zcomp_strm_single_find;
+ comp->strm_release = zcomp_strm_single_release;
+ comp->set_max_streams = zcomp_strm_single_set_max_streams;
+ zs = kmalloc(sizeof(struct zcomp_strm_single), GFP_KERNEL);
+ if (!zs)
+ return -ENOMEM;
+
+ comp->stream = zs;
+ mutex_init(&zs->strm_lock);
+ zs->zstrm = zcomp_strm_alloc(comp);
+ if (!zs->zstrm) {
+ kfree(zs);
+ return -ENOMEM;
+ }
+ return 0;
+}
+
+/* show available compressors */
+ssize_t zcomp_available_show(const char *comp, char *buf)
+{
+ ssize_t sz = 0;
+ int i = 0;
+
+ while (backends[i]) {
+ if (sysfs_streq(comp, backends[i]->name))
+ sz += scnprintf(buf + sz, PAGE_SIZE - sz - 2,
+ "[%s] ", backends[i]->name);
+ else
+ sz += scnprintf(buf + sz, PAGE_SIZE - sz - 2,
+ "%s ", backends[i]->name);
+ i++;
+ }
+ sz += scnprintf(buf + sz, PAGE_SIZE - sz, "\n");
+ return sz;
+}
+
+bool zcomp_set_max_streams(struct zcomp *comp, int num_strm)
+{
+ return comp->set_max_streams(comp, num_strm);
+}
+
+struct zcomp_strm *zcomp_strm_find(struct zcomp *comp)
+{
+ return comp->strm_find(comp);
+}
+
+void zcomp_strm_release(struct zcomp *comp, struct zcomp_strm *zstrm)
+{
+ comp->strm_release(comp, zstrm);
+}
+
+int zcomp_compress(struct zcomp *comp, struct zcomp_strm *zstrm,
+ const unsigned char *src, size_t *dst_len)
+{
+ return comp->backend->compress(src, zstrm->buffer, dst_len,
+ zstrm->private);
+}
+
+int zcomp_decompress(struct zcomp *comp, const unsigned char *src,
+ size_t src_len, unsigned char *dst)
+{
+ return comp->backend->decompress(src, src_len, dst);
+}
+
+void zcomp_destroy(struct zcomp *comp)
+{
+ comp->destroy(comp);
+ kfree(comp);
+}
+
+/*
+ * search available compressors for requested algorithm.
+ * allocate new zcomp and initialize it. return compressing
+ * backend pointer or ERR_PTR if things went bad. ERR_PTR(-EINVAL)
+ * if requested algorithm is not supported, ERR_PTR(-ENOMEM) in
+ * case of allocation error, or any other error potentially
+ * returned by functions zcomp_strm_{multi,single}_create.
+ */
+struct zcomp *zcomp_create(const char *compress, int max_strm)
+{
+ struct zcomp *comp;
+ struct zcomp_backend *backend;
+ int error;
+
+ backend = find_backend(compress);
+ if (!backend)
+ return ERR_PTR(-EINVAL);
+
+ comp = kzalloc(sizeof(struct zcomp), GFP_KERNEL);
+ if (!comp)
+ return ERR_PTR(-ENOMEM);
+
+ comp->backend = backend;
+ if (max_strm > 1)
+ error = zcomp_strm_multi_create(comp, max_strm);
+ else
+ error = zcomp_strm_single_create(comp);
+ if (error) {
+ kfree(comp);
+ return ERR_PTR(error);
+ }
+ return comp;
+}
--- /dev/null
+/*
+ * Copyright (C) 2014 Sergey Senozhatsky.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#ifndef _ZCOMP_H_
+#define _ZCOMP_H_
+
+#include <linux/mutex.h>
+
+struct zcomp_strm {
+ /* compression/decompression buffer */
+ void *buffer;
+ /*
+ * The private data of the compression stream, only compression
+ * stream backend can touch this (e.g. compression algorithm
+ * working memory)
+ */
+ void *private;
+ /* used in multi stream backend, protected by backend strm_lock */
+ struct list_head list;
+};
+
+/* static compression backend */
+struct zcomp_backend {
+ int (*compress)(const unsigned char *src, unsigned char *dst,
+ size_t *dst_len, void *private);
+
+ int (*decompress)(const unsigned char *src, size_t src_len,
+ unsigned char *dst);
+
+ void *(*create)(void);
+ void (*destroy)(void *private);
+
+ const char *name;
+};
+
+/* dynamic per-device compression frontend */
+struct zcomp {
+ void *stream;
+ struct zcomp_backend *backend;
+
+ struct zcomp_strm *(*strm_find)(struct zcomp *comp);
+ void (*strm_release)(struct zcomp *comp, struct zcomp_strm *zstrm);
+ bool (*set_max_streams)(struct zcomp *comp, int num_strm);
+ void (*destroy)(struct zcomp *comp);
+};
+
+ssize_t zcomp_available_show(const char *comp, char *buf);
+
+struct zcomp *zcomp_create(const char *comp, int max_strm);
+void zcomp_destroy(struct zcomp *comp);
+
+struct zcomp_strm *zcomp_strm_find(struct zcomp *comp);
+void zcomp_strm_release(struct zcomp *comp, struct zcomp_strm *zstrm);
+
+int zcomp_compress(struct zcomp *comp, struct zcomp_strm *zstrm,
+ const unsigned char *src, size_t *dst_len);
+
+int zcomp_decompress(struct zcomp *comp, const unsigned char *src,
+ size_t src_len, unsigned char *dst);
+
+bool zcomp_set_max_streams(struct zcomp *comp, int num_strm);
+#endif /* _ZCOMP_H_ */
--- /dev/null
+/*
+ * Copyright (C) 2014 Sergey Senozhatsky.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/lz4.h>
+#include <linux/vmalloc.h>
+#include <linux/mm.h>
+
+#include "zcomp_lz4.h"
+
+static void *zcomp_lz4_create(void)
+{
+ void *ret;
+
+ /*
+ * This function can be called in swapout/fs write path
+ * so we can't use GFP_FS|IO. And it assumes we already
+ * have at least one stream in zram initialization so we
+ * don't do best effort to allocate more stream in here.
+ * A default stream will work well without further multiple
+ * streams. That's why we use NORETRY | NOWARN.
+ */
+ ret = kzalloc(LZ4_MEM_COMPRESS, GFP_NOIO | __GFP_NORETRY |
+ __GFP_NOWARN);
+ if (!ret)
+ ret = __vmalloc(LZ4_MEM_COMPRESS,
+ GFP_NOIO | __GFP_NORETRY | __GFP_NOWARN |
+ __GFP_ZERO | __GFP_HIGHMEM,
+ PAGE_KERNEL);
+ return ret;
+}
+
+static void zcomp_lz4_destroy(void *private)
+{
+ kvfree(private);
+}
+
+static int zcomp_lz4_compress(const unsigned char *src, unsigned char *dst,
+ size_t *dst_len, void *private)
+{
+ /* return : Success if return 0 */
+ return lz4_compress(src, PAGE_SIZE, dst, dst_len, private);
+}
+
+static int zcomp_lz4_decompress(const unsigned char *src, size_t src_len,
+ unsigned char *dst)
+{
+ size_t dst_len = PAGE_SIZE;
+ /* return : Success if return 0 */
+ return lz4_decompress_unknownoutputsize(src, src_len, dst, &dst_len);
+}
+
+struct zcomp_backend zcomp_lz4 = {
+ .compress = zcomp_lz4_compress,
+ .decompress = zcomp_lz4_decompress,
+ .create = zcomp_lz4_create,
+ .destroy = zcomp_lz4_destroy,
+ .name = "lz4",
+};
--- /dev/null
+/*
+ * Copyright (C) 2014 Sergey Senozhatsky.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#ifndef _ZCOMP_LZ4_H_
+#define _ZCOMP_LZ4_H_
+
+#include "zcomp.h"
+
+extern struct zcomp_backend zcomp_lz4;
+
+#endif /* _ZCOMP_LZ4_H_ */
--- /dev/null
+/*
+ * Copyright (C) 2014 Sergey Senozhatsky.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/lzo.h>
+#include <linux/vmalloc.h>
+#include <linux/mm.h>
+
+#include "zcomp_lzo.h"
+
+static void *lzo_create(void)
+{
+ void *ret;
+
+ /*
+ * This function can be called in swapout/fs write path
+ * so we can't use GFP_FS|IO. And it assumes we already
+ * have at least one stream in zram initialization so we
+ * don't do best effort to allocate more stream in here.
+ * A default stream will work well without further multiple
+ * streams. That's why we use NORETRY | NOWARN.
+ */
+ ret = kzalloc(LZO1X_MEM_COMPRESS, GFP_NOIO | __GFP_NORETRY |
+ __GFP_NOWARN);
+ if (!ret)
+ ret = __vmalloc(LZO1X_MEM_COMPRESS,
+ GFP_NOIO | __GFP_NORETRY | __GFP_NOWARN |
+ __GFP_ZERO | __GFP_HIGHMEM,
+ PAGE_KERNEL);
+ return ret;
+}
+
+static void lzo_destroy(void *private)
+{
+ kvfree(private);
+}
+
+static int lzo_compress(const unsigned char *src, unsigned char *dst,
+ size_t *dst_len, void *private)
+{
+ int ret = lzo1x_1_compress(src, PAGE_SIZE, dst, dst_len, private);
+ return ret == LZO_E_OK ? 0 : ret;
+}
+
+static int lzo_decompress(const unsigned char *src, size_t src_len,
+ unsigned char *dst)
+{
+ size_t dst_len = PAGE_SIZE;
+ int ret = lzo1x_decompress_safe(src, src_len, dst, &dst_len);
+ return ret == LZO_E_OK ? 0 : ret;
+}
+
+struct zcomp_backend zcomp_lzo = {
+ .compress = lzo_compress,
+ .decompress = lzo_decompress,
+ .create = lzo_create,
+ .destroy = lzo_destroy,
+ .name = "lzo",
+};
--- /dev/null
+/*
+ * Copyright (C) 2014 Sergey Senozhatsky.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#ifndef _ZCOMP_LZO_H_
+#define _ZCOMP_LZO_H_
+
+#include "zcomp.h"
+
+extern struct zcomp_backend zcomp_lzo;
+
+#endif /* _ZCOMP_LZO_H_ */
--- /dev/null
+/*
+ * Compressed RAM block device
+ *
+ * Copyright (C) 2008, 2009, 2010 Nitin Gupta
+ * 2012, 2013 Minchan Kim
+ *
+ * This code is released using a dual license strategy: BSD/GPL
+ * You can choose the licence that better fits your requirements.
+ *
+ * Released under the terms of 3-clause BSD License
+ * Released under the terms of GNU General Public License Version 2.0
+ *
+ */
+
+#define KMSG_COMPONENT "zram"
+#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
+
+#ifdef CONFIG_ZRAM_DEBUG
+#define DEBUG
+#endif
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/bio.h>
+#include <linux/bitops.h>
+#include <linux/blkdev.h>
+#include <linux/buffer_head.h>
+#include <linux/device.h>
+#include <linux/genhd.h>
+#include <linux/highmem.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/vmalloc.h>
+#include <linux/err.h>
+
+#include "zram_drv.h"
+
+/* Globals */
+static int zram_major;
+static struct zram *zram_devices;
+static const char *default_compressor = "lzo";
+
+/* Module params (documentation at end) */
+static unsigned int num_devices = 1;
+
+static inline void deprecated_attr_warn(const char *name)
+{
+ pr_warn_once("%d (%s) Attribute %s (and others) will be removed. %s\n",
+ task_pid_nr(current),
+ current->comm,
+ name,
+ "See zram documentation.");
+}
+
+#define ZRAM_ATTR_RO(name) \
+static ssize_t name##_show(struct device *d, \
+ struct device_attribute *attr, char *b) \
+{ \
+ struct zram *zram = dev_to_zram(d); \
+ \
+ deprecated_attr_warn(__stringify(name)); \
+ return scnprintf(b, PAGE_SIZE, "%llu\n", \
+ (u64)atomic64_read(&zram->stats.name)); \
+} \
+static DEVICE_ATTR_RO(name);
+
+static inline bool init_done(struct zram *zram)
+{
+ return zram->disksize;
+}
+
+static inline struct zram *dev_to_zram(struct device *dev)
+{
+ return (struct zram *)dev_to_disk(dev)->private_data;
+}
+
+static ssize_t compact_store(struct device *dev,
+ struct device_attribute *attr, const char *buf, size_t len)
+{
+ unsigned long nr_migrated;
+ struct zram *zram = dev_to_zram(dev);
+ struct zram_meta *meta;
+
+ down_read(&zram->init_lock);
+ if (!init_done(zram)) {
+ up_read(&zram->init_lock);
+ return -EINVAL;
+ }
+
+ meta = zram->meta;
+ nr_migrated = zs_compact(meta->mem_pool);
+ atomic64_add(nr_migrated, &zram->stats.num_migrated);
+ up_read(&zram->init_lock);
+
+ return len;
+}
+
+static ssize_t disksize_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct zram *zram = dev_to_zram(dev);
+
+ return scnprintf(buf, PAGE_SIZE, "%llu\n", zram->disksize);
+}
+
+static ssize_t initstate_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ u32 val;
+ struct zram *zram = dev_to_zram(dev);
+
+ down_read(&zram->init_lock);
+ val = init_done(zram);
+ up_read(&zram->init_lock);
+
+ return scnprintf(buf, PAGE_SIZE, "%u\n", val);
+}
+
+static ssize_t orig_data_size_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct zram *zram = dev_to_zram(dev);
+
+ deprecated_attr_warn("orig_data_size");
+ return scnprintf(buf, PAGE_SIZE, "%llu\n",
+ (u64)(atomic64_read(&zram->stats.pages_stored)) << PAGE_SHIFT);
+}
+
+static ssize_t mem_used_total_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ u64 val = 0;
+ struct zram *zram = dev_to_zram(dev);
+
+ deprecated_attr_warn("mem_used_total");
+ down_read(&zram->init_lock);
+ if (init_done(zram)) {
+ struct zram_meta *meta = zram->meta;
+ val = zs_get_total_pages(meta->mem_pool);
+ }
+ up_read(&zram->init_lock);
+
+ return scnprintf(buf, PAGE_SIZE, "%llu\n", val << PAGE_SHIFT);
+}
+
+static ssize_t max_comp_streams_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ int val;
+ struct zram *zram = dev_to_zram(dev);
+
+ down_read(&zram->init_lock);
+ val = zram->max_comp_streams;
+ up_read(&zram->init_lock);
+
+ return scnprintf(buf, PAGE_SIZE, "%d\n", val);
+}
+
+static ssize_t mem_limit_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ u64 val;
+ struct zram *zram = dev_to_zram(dev);
+
+ deprecated_attr_warn("mem_limit");
+ down_read(&zram->init_lock);
+ val = zram->limit_pages;
+ up_read(&zram->init_lock);
+
+ return scnprintf(buf, PAGE_SIZE, "%llu\n", val << PAGE_SHIFT);
+}
+
+static ssize_t mem_limit_store(struct device *dev,
+ struct device_attribute *attr, const char *buf, size_t len)
+{
+ u64 limit;
+ char *tmp;
+ struct zram *zram = dev_to_zram(dev);
+
+ limit = memparse(buf, &tmp);
+ if (buf == tmp) /* no chars parsed, invalid input */
+ return -EINVAL;
+
+ down_write(&zram->init_lock);
+ zram->limit_pages = PAGE_ALIGN(limit) >> PAGE_SHIFT;
+ up_write(&zram->init_lock);
+
+ return len;
+}
+
+static ssize_t mem_used_max_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ u64 val = 0;
+ struct zram *zram = dev_to_zram(dev);
+
+ deprecated_attr_warn("mem_used_max");
+ down_read(&zram->init_lock);
+ if (init_done(zram))
+ val = atomic_long_read(&zram->stats.max_used_pages);
+ up_read(&zram->init_lock);
+
+ return scnprintf(buf, PAGE_SIZE, "%llu\n", val << PAGE_SHIFT);
+}
+
+static ssize_t mem_used_max_store(struct device *dev,
+ struct device_attribute *attr, const char *buf, size_t len)
+{
+ int err;
+ unsigned long val;
+ struct zram *zram = dev_to_zram(dev);
+
+ err = kstrtoul(buf, 10, &val);
+ if (err || val != 0)
+ return -EINVAL;
+
+ down_read(&zram->init_lock);
+ if (init_done(zram)) {
+ struct zram_meta *meta = zram->meta;
+ atomic_long_set(&zram->stats.max_used_pages,
+ zs_get_total_pages(meta->mem_pool));
+ }
+ up_read(&zram->init_lock);
+
+ return len;
+}
+
+static ssize_t max_comp_streams_store(struct device *dev,
+ struct device_attribute *attr, const char *buf, size_t len)
+{
+ int num;
+ struct zram *zram = dev_to_zram(dev);
+ int ret;
+
+ ret = kstrtoint(buf, 0, &num);
+ if (ret < 0)
+ return ret;
+ if (num < 1)
+ return -EINVAL;
+
+ down_write(&zram->init_lock);
+ if (init_done(zram)) {
+ if (!zcomp_set_max_streams(zram->comp, num)) {
+ pr_info("Cannot change max compression streams\n");
+ ret = -EINVAL;
+ goto out;
+ }
+ }
+
+ zram->max_comp_streams = num;
+ ret = len;
+out:
+ up_write(&zram->init_lock);
+ return ret;
+}
+
+static ssize_t comp_algorithm_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ size_t sz;
+ struct zram *zram = dev_to_zram(dev);
+
+ down_read(&zram->init_lock);
+ sz = zcomp_available_show(zram->compressor, buf);
+ up_read(&zram->init_lock);
+
+ return sz;
+}
+
+static ssize_t comp_algorithm_store(struct device *dev,
+ struct device_attribute *attr, const char *buf, size_t len)
+{
+ struct zram *zram = dev_to_zram(dev);
+ down_write(&zram->init_lock);
+ if (init_done(zram)) {
+ up_write(&zram->init_lock);
+ pr_info("Can't change algorithm for initialized device\n");
+ return -EBUSY;
+ }
+ strlcpy(zram->compressor, buf, sizeof(zram->compressor));
+ up_write(&zram->init_lock);
+ return len;
+}
+
+/* flag operations needs meta->tb_lock */
+static int zram_test_flag(struct zram_meta *meta, u32 index,
+ enum zram_pageflags flag)
+{
+ return meta->table[index].value & BIT(flag);
+}
+
+static void zram_set_flag(struct zram_meta *meta, u32 index,
+ enum zram_pageflags flag)
+{
+ meta->table[index].value |= BIT(flag);
+}
+
+static void zram_clear_flag(struct zram_meta *meta, u32 index,
+ enum zram_pageflags flag)
+{
+ meta->table[index].value &= ~BIT(flag);
+}
+
+static size_t zram_get_obj_size(struct zram_meta *meta, u32 index)
+{
+ return meta->table[index].value & (BIT(ZRAM_FLAG_SHIFT) - 1);
+}
+
+static void zram_set_obj_size(struct zram_meta *meta,
+ u32 index, size_t size)
+{
+ unsigned long flags = meta->table[index].value >> ZRAM_FLAG_SHIFT;
+
+ meta->table[index].value = (flags << ZRAM_FLAG_SHIFT) | size;
+}
+
+static inline int is_partial_io(struct bio_vec *bvec)
+{
+ return bvec->bv_len != PAGE_SIZE;
+}
+
+/*
+ * Check if request is within bounds and aligned on zram logical blocks.
+ */
+static inline int valid_io_request(struct zram *zram,
+ sector_t start, unsigned int size)
+{
+ u64 end, bound;
+
+ /* unaligned request */
+ if (unlikely(start & (ZRAM_SECTOR_PER_LOGICAL_BLOCK - 1)))
+ return 0;
+ if (unlikely(size & (ZRAM_LOGICAL_BLOCK_SIZE - 1)))
+ return 0;
+
+ end = start + (size >> SECTOR_SHIFT);
+ bound = zram->disksize >> SECTOR_SHIFT;
+ /* out of range range */
+ if (unlikely(start >= bound || end > bound || start > end))
+ return 0;
+
+ /* I/O request is valid */
+ return 1;
+}
+
+static void zram_meta_free(struct zram_meta *meta, u64 disksize)
+{
+ size_t num_pages = disksize >> PAGE_SHIFT;
+ size_t index;
+
+ /* Free all pages that are still in this zram device */
+ for (index = 0; index < num_pages; index++) {
+ unsigned long handle = meta->table[index].handle;
+
+ if (!handle)
+ continue;
+
+ zs_free(meta->mem_pool, handle);
+ }
+
+ zs_destroy_pool(meta->mem_pool);
+ vfree(meta->table);
+ kfree(meta);
+}
+
+static struct zram_meta *zram_meta_alloc(int device_id, u64 disksize)
+{
+ size_t num_pages;
+ char pool_name[8];
+ struct zram_meta *meta = kmalloc(sizeof(*meta), GFP_KERNEL);
+
+ if (!meta)
+ return NULL;
+
+ num_pages = disksize >> PAGE_SHIFT;
+ meta->table = vzalloc(num_pages * sizeof(*meta->table));
+ if (!meta->table) {
+ pr_err("Error allocating zram address table\n");
+ goto out_error;
+ }
+
+ snprintf(pool_name, sizeof(pool_name), "zram%d", device_id);
+ meta->mem_pool = zs_create_pool(pool_name, GFP_NOIO | __GFP_HIGHMEM);
+ if (!meta->mem_pool) {
+ pr_err("Error creating memory pool\n");
+ goto out_error;
+ }
+
+ return meta;
+
+out_error:
+ vfree(meta->table);
+ kfree(meta);
+ return NULL;
+}
+
+static inline bool zram_meta_get(struct zram *zram)
+{
+ if (atomic_inc_not_zero(&zram->refcount))
+ return true;
+ return false;
+}
+
+static inline void zram_meta_put(struct zram *zram)
+{
+ atomic_dec(&zram->refcount);
+}
+
+static void update_position(u32 *index, int *offset, struct bio_vec *bvec)
+{
+ if (*offset + bvec->bv_len >= PAGE_SIZE)
+ (*index)++;
+ *offset = (*offset + bvec->bv_len) % PAGE_SIZE;
+}
+
+static int page_zero_filled(void *ptr)
+{
+ unsigned int pos;
+ unsigned long *page;
+
+ page = (unsigned long *)ptr;
+
+ for (pos = 0; pos != PAGE_SIZE / sizeof(*page); pos++) {
+ if (page[pos])
+ return 0;
+ }
+
+ return 1;
+}
+
+static void handle_zero_page(struct bio_vec *bvec)
+{
+ struct page *page = bvec->bv_page;
+ void *user_mem;
+
+ user_mem = kmap_atomic(page);
+ if (is_partial_io(bvec))
+ memset(user_mem + bvec->bv_offset, 0, bvec->bv_len);
+ else
+ clear_page(user_mem);
+ kunmap_atomic(user_mem);
+
+ flush_dcache_page(page);
+}
+
+
+/*
+ * To protect concurrent access to the same index entry,
+ * caller should hold this table index entry's bit_spinlock to
+ * indicate this index entry is accessing.
+ */
+static void zram_free_page(struct zram *zram, size_t index)
+{
+ struct zram_meta *meta = zram->meta;
+ unsigned long handle = meta->table[index].handle;
+
+ if (unlikely(!handle)) {
+ /*
+ * No memory is allocated for zero filled pages.
+ * Simply clear zero page flag.
+ */
+ if (zram_test_flag(meta, index, ZRAM_ZERO)) {
+ zram_clear_flag(meta, index, ZRAM_ZERO);
+ atomic64_dec(&zram->stats.zero_pages);
+ }
+ return;
+ }
+
+ zs_free(meta->mem_pool, handle);
+
+ atomic64_sub(zram_get_obj_size(meta, index),
+ &zram->stats.compr_data_size);
+ atomic64_dec(&zram->stats.pages_stored);
+
+ meta->table[index].handle = 0;
+ zram_set_obj_size(meta, index, 0);
+}
+
+static int zram_decompress_page(struct zram *zram, char *mem, u32 index)
+{
+ int ret = 0;
+ unsigned char *cmem;
+ struct zram_meta *meta = zram->meta;
+ unsigned long handle;
+ size_t size;
+
+ bit_spin_lock(ZRAM_ACCESS, &meta->table[index].value);
+ handle = meta->table[index].handle;
+ size = zram_get_obj_size(meta, index);
+
+ if (!handle || zram_test_flag(meta, index, ZRAM_ZERO)) {
+ bit_spin_unlock(ZRAM_ACCESS, &meta->table[index].value);
+ clear_page(mem);
+ return 0;
+ }
+
+ cmem = zs_map_object(meta->mem_pool, handle, ZS_MM_RO);
+ if (size == PAGE_SIZE)
+ copy_page(mem, cmem);
+ else
+ ret = zcomp_decompress(zram->comp, cmem, size, mem);
+ zs_unmap_object(meta->mem_pool, handle);
+ bit_spin_unlock(ZRAM_ACCESS, &meta->table[index].value);
+
+ /* Should NEVER happen. Return bio error if it does. */
+ if (unlikely(ret)) {
+ pr_err("Decompression failed! err=%d, page=%u\n", ret, index);
+ return ret;
+ }
+
+ return 0;
+}
+
+static int zram_bvec_read(struct zram *zram, struct bio_vec *bvec,
+ u32 index, int offset)
+{
+ int ret;
+ struct page *page;
+ unsigned char *user_mem, *uncmem = NULL;
+ struct zram_meta *meta = zram->meta;
+ page = bvec->bv_page;
+
+ bit_spin_lock(ZRAM_ACCESS, &meta->table[index].value);
+ if (unlikely(!meta->table[index].handle) ||
+ zram_test_flag(meta, index, ZRAM_ZERO)) {
+ bit_spin_unlock(ZRAM_ACCESS, &meta->table[index].value);
+ handle_zero_page(bvec);
+ return 0;
+ }
+ bit_spin_unlock(ZRAM_ACCESS, &meta->table[index].value);
+
+ if (is_partial_io(bvec))
+ /* Use a temporary buffer to decompress the page */
+ uncmem = kmalloc(PAGE_SIZE, GFP_NOIO);
+
+ user_mem = kmap_atomic(page);
+ if (!is_partial_io(bvec))
+ uncmem = user_mem;
+
+ if (!uncmem) {
+ pr_info("Unable to allocate temp memory\n");
+ ret = -ENOMEM;
+ goto out_cleanup;
+ }
+
+ ret = zram_decompress_page(zram, uncmem, index);
+ /* Should NEVER happen. Return bio error if it does. */
+ if (unlikely(ret))
+ goto out_cleanup;
+
+ if (is_partial_io(bvec))
+ memcpy(user_mem + bvec->bv_offset, uncmem + offset,
+ bvec->bv_len);
+
+ flush_dcache_page(page);
+ ret = 0;
+out_cleanup:
+ kunmap_atomic(user_mem);
+ if (is_partial_io(bvec))
+ kfree(uncmem);
+ return ret;
+}
+
+static inline void update_used_max(struct zram *zram,
+ const unsigned long pages)
+{
+ unsigned long old_max, cur_max;
+
+ old_max = atomic_long_read(&zram->stats.max_used_pages);
+
+ do {
+ cur_max = old_max;
+ if (pages > cur_max)
+ old_max = atomic_long_cmpxchg(
+ &zram->stats.max_used_pages, cur_max, pages);
+ } while (old_max != cur_max);
+}
+
+static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index,
+ int offset)
+{
+ int ret = 0;
+ size_t clen;
+ unsigned long handle;
+ struct page *page;
+ unsigned char *user_mem, *cmem, *src, *uncmem = NULL;
+ struct zram_meta *meta = zram->meta;
+ struct zcomp_strm *zstrm;
+ bool locked = false;
+ unsigned long alloced_pages;
+
+ page = bvec->bv_page;
+ if (is_partial_io(bvec)) {
+ /*
+ * This is a partial IO. We need to read the full page
+ * before to write the changes.
+ */
+ uncmem = kmalloc(PAGE_SIZE, GFP_NOIO);
+ if (!uncmem) {
+ ret = -ENOMEM;
+ goto out;
+ }
+ ret = zram_decompress_page(zram, uncmem, index);
+ if (ret)
+ goto out;
+ }
+
+ zstrm = zcomp_strm_find(zram->comp);
+ locked = true;
+ user_mem = kmap_atomic(page);
+
+ if (is_partial_io(bvec)) {
+ memcpy(uncmem + offset, user_mem + bvec->bv_offset,
+ bvec->bv_len);
+ kunmap_atomic(user_mem);
+ user_mem = NULL;
+ } else {
+ uncmem = user_mem;
+ }
+
+ if (page_zero_filled(uncmem)) {
+ if (user_mem)
+ kunmap_atomic(user_mem);
+ /* Free memory associated with this sector now. */
+ bit_spin_lock(ZRAM_ACCESS, &meta->table[index].value);
+ zram_free_page(zram, index);
+ zram_set_flag(meta, index, ZRAM_ZERO);
+ bit_spin_unlock(ZRAM_ACCESS, &meta->table[index].value);
+
+ atomic64_inc(&zram->stats.zero_pages);
+ ret = 0;
+ goto out;
+ }
+
+ ret = zcomp_compress(zram->comp, zstrm, uncmem, &clen);
+ if (!is_partial_io(bvec)) {
+ kunmap_atomic(user_mem);
+ user_mem = NULL;
+ uncmem = NULL;
+ }
+
+ if (unlikely(ret)) {
+ pr_err("Compression failed! err=%d\n", ret);
+ goto out;
+ }
+ src = zstrm->buffer;
+ if (unlikely(clen > max_zpage_size)) {
+ clen = PAGE_SIZE;
+ if (is_partial_io(bvec))
+ src = uncmem;
+ }
+
+ handle = zs_malloc(meta->mem_pool, clen);
+ if (!handle) {
+ pr_info("Error allocating memory for compressed page: %u, size=%zu\n",
+ index, clen);
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ alloced_pages = zs_get_total_pages(meta->mem_pool);
+ if (zram->limit_pages && alloced_pages > zram->limit_pages) {
+ zs_free(meta->mem_pool, handle);
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ update_used_max(zram, alloced_pages);
+
+ cmem = zs_map_object(meta->mem_pool, handle, ZS_MM_WO);
+
+ if ((clen == PAGE_SIZE) && !is_partial_io(bvec)) {
+ src = kmap_atomic(page);
+ copy_page(cmem, src);
+ kunmap_atomic(src);
+ } else {
+ memcpy(cmem, src, clen);
+ }
+
+ zcomp_strm_release(zram->comp, zstrm);
+ locked = false;
+ zs_unmap_object(meta->mem_pool, handle);
+
+ /*
+ * Free memory associated with this sector
+ * before overwriting unused sectors.
+ */
+ bit_spin_lock(ZRAM_ACCESS, &meta->table[index].value);
+ zram_free_page(zram, index);
+
+ meta->table[index].handle = handle;
+ zram_set_obj_size(meta, index, clen);
+ bit_spin_unlock(ZRAM_ACCESS, &meta->table[index].value);
+
+ /* Update stats */
+ atomic64_add(clen, &zram->stats.compr_data_size);
+ atomic64_inc(&zram->stats.pages_stored);
+out:
+ if (locked)
+ zcomp_strm_release(zram->comp, zstrm);
+ if (is_partial_io(bvec))
+ kfree(uncmem);
+ return ret;
+}
+
+static int zram_bvec_rw(struct zram *zram, struct bio_vec *bvec, u32 index,
+ int offset, int rw)
+{
+ unsigned long start_time = jiffies;
+ int ret;
+
+ generic_start_io_acct(rw, bvec->bv_len >> SECTOR_SHIFT,
+ &zram->disk->part0);
+
+ if (rw == READ) {
+ atomic64_inc(&zram->stats.num_reads);
+ ret = zram_bvec_read(zram, bvec, index, offset);
+ } else {
+ atomic64_inc(&zram->stats.num_writes);
+ ret = zram_bvec_write(zram, bvec, index, offset);
+ }
+
+ generic_end_io_acct(rw, &zram->disk->part0, start_time);
+
+ if (unlikely(ret)) {
+ if (rw == READ)
+ atomic64_inc(&zram->stats.failed_reads);
+ else
+ atomic64_inc(&zram->stats.failed_writes);
+ }
+
+ return ret;
+}
+
+/*
+ * zram_bio_discard - handler on discard request
+ * @index: physical block index in PAGE_SIZE units
+ * @offset: byte offset within physical block
+ */
+static void zram_bio_discard(struct zram *zram, u32 index,
+ int offset, struct bio *bio)
+{
+ size_t n = bio->bi_size;
+ struct zram_meta *meta = zram->meta;
+
+ /*
+ * zram manages data in physical block size units. Because logical block
+ * size isn't identical with physical block size on some arch, we
+ * could get a discard request pointing to a specific offset within a
+ * certain physical block. Although we can handle this request by
+ * reading that physiclal block and decompressing and partially zeroing
+ * and re-compressing and then re-storing it, this isn't reasonable
+ * because our intent with a discard request is to save memory. So
+ * skipping this logical block is appropriate here.
+ */
+ if (offset) {
+ if (n <= (PAGE_SIZE - offset))
+ return;
+
+ n -= (PAGE_SIZE - offset);
+ index++;
+ }
+
+ while (n >= PAGE_SIZE) {
+ bit_spin_lock(ZRAM_ACCESS, &meta->table[index].value);
+ zram_free_page(zram, index);
+ bit_spin_unlock(ZRAM_ACCESS, &meta->table[index].value);
+ atomic64_inc(&zram->stats.notify_free);
+ index++;
+ n -= PAGE_SIZE;
+ }
+}
+
+static void zram_reset_device(struct zram *zram)
+{
+ struct zram_meta *meta;
+ struct zcomp *comp;
+ u64 disksize;
+
+ down_write(&zram->init_lock);
+
+ zram->limit_pages = 0;
+
+ if (!init_done(zram)) {
+ up_write(&zram->init_lock);
+ return;
+ }
+
+ meta = zram->meta;
+ comp = zram->comp;
+ disksize = zram->disksize;
+ /*
+ * Refcount will go down to 0 eventually and r/w handler
+ * cannot handle further I/O so it will bail out by
+ * check zram_meta_get.
+ */
+ zram_meta_put(zram);
+ /*
+ * We want to free zram_meta in process context to avoid
+ * deadlock between reclaim path and any other locks.
+ */
+ wait_event(zram->io_done, atomic_read(&zram->refcount) == 0);
+
+ /* Reset stats */
+ memset(&zram->stats, 0, sizeof(zram->stats));
+ zram->disksize = 0;
+ zram->max_comp_streams = 1;
+
+ set_capacity(zram->disk, 0);
+ part_stat_set_all(&zram->disk->part0, 0);
+
+ up_write(&zram->init_lock);
+ /* I/O operation under all of CPU are done so let's free */
+ zram_meta_free(meta, disksize);
+ zcomp_destroy(comp);
+}
+
+static ssize_t disksize_store(struct device *dev,
+ struct device_attribute *attr, const char *buf, size_t len)
+{
+ u64 disksize;
+ struct zcomp *comp;
+ struct zram_meta *meta;
+ struct zram *zram = dev_to_zram(dev);
+ int err;
+
+ disksize = memparse(buf, NULL);
+ if (!disksize)
+ return -EINVAL;
+
+ disksize = PAGE_ALIGN(disksize);
+ meta = zram_meta_alloc(zram->disk->first_minor, disksize);
+ if (!meta)
+ return -ENOMEM;
+
+ comp = zcomp_create(zram->compressor, zram->max_comp_streams);
+ if (IS_ERR(comp)) {
+ pr_info("Cannot initialise %s compressing backend\n",
+ zram->compressor);
+ err = PTR_ERR(comp);
+ goto out_free_meta;
+ }
+
+ down_write(&zram->init_lock);
+ if (init_done(zram)) {
+ pr_info("Cannot change disksize for initialized device\n");
+ err = -EBUSY;
+ goto out_destroy_comp;
+ }
+
+ init_waitqueue_head(&zram->io_done);
+ atomic_set(&zram->refcount, 1);
+ zram->meta = meta;
+ zram->comp = comp;
+ zram->disksize = disksize;
+ set_capacity(zram->disk, zram->disksize >> SECTOR_SHIFT);
+ up_write(&zram->init_lock);
+
+ /*
+ * Revalidate disk out of the init_lock to avoid lockdep splat.
+ * It's okay because disk's capacity is protected by init_lock
+ * so that revalidate_disk always sees up-to-date capacity.
+ */
+ revalidate_disk(zram->disk);
+
+ return len;
+
+out_destroy_comp:
+ up_write(&zram->init_lock);
+ zcomp_destroy(comp);
+out_free_meta:
+ zram_meta_free(meta, disksize);
+ return err;
+}
+
+static ssize_t reset_store(struct device *dev,
+ struct device_attribute *attr, const char *buf, size_t len)
+{
+ int ret;
+ unsigned short do_reset;
+ struct zram *zram;
+ struct block_device *bdev;
+
+ zram = dev_to_zram(dev);
+ bdev = bdget_disk(zram->disk, 0);
+
+ if (!bdev)
+ return -ENOMEM;
+
+ mutex_lock(&bdev->bd_mutex);
+ /* Do not reset an active device! */
+ if (bdev->bd_openers) {
+ ret = -EBUSY;
+ goto out;
+ }
+
+ ret = kstrtou16(buf, 10, &do_reset);
+ if (ret)
+ goto out;
+
+ if (!do_reset) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ /* Make sure all pending I/O is finished */
+ fsync_bdev(bdev);
+ zram_reset_device(zram);
+
+ mutex_unlock(&bdev->bd_mutex);
+ revalidate_disk(zram->disk);
+ bdput(bdev);
+
+ return len;
+
+out:
+ mutex_unlock(&bdev->bd_mutex);
+ bdput(bdev);
+ return ret;
+}
+
+static void __zram_make_request(struct zram *zram, struct bio *bio)
+{
+ int i, offset, rw;
+ u32 index;
+ struct bio_vec *bvec;
+
+ index = bio->bi_sector >> SECTORS_PER_PAGE_SHIFT;
+ offset = (bio->bi_sector &
+ (SECTORS_PER_PAGE - 1)) << SECTOR_SHIFT;
+
+ if (unlikely(bio->bi_rw & REQ_DISCARD)) {
+ zram_bio_discard(zram, index, offset, bio);
+ bio_endio(bio, 0);
+ return;
+ }
+
+ rw = bio_data_dir(bio);
+ bio_for_each_segment(bvec, bio, i) {
+ int max_transfer_size = PAGE_SIZE - offset;
+
+ if (bvec->bv_len > max_transfer_size) {
+ /*
+ * zram_bvec_rw() can only make operation on a single
+ * zram page. Split the bio vector.
+ */
+ struct bio_vec bv;
+
+ bv.bv_page = bvec->bv_page;
+ bv.bv_len = max_transfer_size;
+ bv.bv_offset = bvec->bv_offset;
+
+ if (zram_bvec_rw(zram, &bv, index, offset, rw) < 0)
+ goto out;
+
+ bv.bv_len = bvec->bv_len - max_transfer_size;
+ bv.bv_offset += max_transfer_size;
+ if (zram_bvec_rw(zram, &bv, index + 1, 0, rw) < 0)
+ goto out;
+ } else
+ if (zram_bvec_rw(zram, bvec, index, offset, rw) < 0)
+ goto out;
+
+ update_position(&index, &offset, bvec);
+ }
+
+ set_bit(BIO_UPTODATE, &bio->bi_flags);
+ bio_endio(bio, 0);
+ return;
+
+out:
+ bio_io_error(bio);
+}
+
+/*
+ * Handler function for all zram I/O requests.
+ */
+static void zram_make_request(struct request_queue *queue, struct bio *bio)
+{
+ struct zram *zram = queue->queuedata;
+
+ if (unlikely(!zram_meta_get(zram)))
+ goto error;
+
+ if (!valid_io_request(zram, bio->bi_sector,
+ bio->bi_size)) {
+ atomic64_inc(&zram->stats.invalid_io);
+ goto put_zram;
+ }
+
+ __zram_make_request(zram, bio);
+ zram_meta_put(zram);
+ return;
+put_zram:
+ zram_meta_put(zram);
+error:
+ bio_io_error(bio);
+}
+
+static void zram_slot_free_notify(struct block_device *bdev,
+ unsigned long index)
+{
+ struct zram *zram;
+ struct zram_meta *meta;
+
+ zram = bdev->bd_disk->private_data;
+ meta = zram->meta;
+
+ bit_spin_lock(ZRAM_ACCESS, &meta->table[index].value);
+ zram_free_page(zram, index);
+ bit_spin_unlock(ZRAM_ACCESS, &meta->table[index].value);
+ atomic64_inc(&zram->stats.notify_free);
+}
+
+static const struct block_device_operations zram_devops = {
+ .swap_slot_free_notify = zram_slot_free_notify,
+ .owner = THIS_MODULE
+};
+
+static DEVICE_ATTR_WO(compact);
+static DEVICE_ATTR_RW(disksize);
+static DEVICE_ATTR_RO(initstate);
+static DEVICE_ATTR_WO(reset);
+static DEVICE_ATTR_RO(orig_data_size);
+static DEVICE_ATTR_RO(mem_used_total);
+static DEVICE_ATTR_RW(mem_limit);
+static DEVICE_ATTR_RW(mem_used_max);
+static DEVICE_ATTR_RW(max_comp_streams);
+static DEVICE_ATTR_RW(comp_algorithm);
+
+static ssize_t io_stat_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct zram *zram = dev_to_zram(dev);
+ ssize_t ret;
+
+ down_read(&zram->init_lock);
+ ret = scnprintf(buf, PAGE_SIZE,
+ "%8llu %8llu %8llu %8llu\n",
+ (u64)atomic64_read(&zram->stats.failed_reads),
+ (u64)atomic64_read(&zram->stats.failed_writes),
+ (u64)atomic64_read(&zram->stats.invalid_io),
+ (u64)atomic64_read(&zram->stats.notify_free));
+ up_read(&zram->init_lock);
+
+ return ret;
+}
+
+static ssize_t mm_stat_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct zram *zram = dev_to_zram(dev);
+ u64 orig_size, mem_used = 0;
+ long max_used;
+ ssize_t ret;
+
+ down_read(&zram->init_lock);
+ if (init_done(zram))
+ mem_used = zs_get_total_pages(zram->meta->mem_pool);
+
+ orig_size = atomic64_read(&zram->stats.pages_stored);
+ max_used = atomic_long_read(&zram->stats.max_used_pages);
+
+ ret = scnprintf(buf, PAGE_SIZE,
+ "%8llu %8llu %8llu %8lu %8ld %8llu %8llu\n",
+ orig_size << PAGE_SHIFT,
+ (u64)atomic64_read(&zram->stats.compr_data_size),
+ mem_used << PAGE_SHIFT,
+ zram->limit_pages << PAGE_SHIFT,
+ max_used << PAGE_SHIFT,
+ (u64)atomic64_read(&zram->stats.zero_pages),
+ (u64)atomic64_read(&zram->stats.num_migrated));
+ up_read(&zram->init_lock);
+
+ return ret;
+}
+
+static DEVICE_ATTR_RO(io_stat);
+static DEVICE_ATTR_RO(mm_stat);
+ZRAM_ATTR_RO(num_reads);
+ZRAM_ATTR_RO(num_writes);
+ZRAM_ATTR_RO(failed_reads);
+ZRAM_ATTR_RO(failed_writes);
+ZRAM_ATTR_RO(invalid_io);
+ZRAM_ATTR_RO(notify_free);
+ZRAM_ATTR_RO(zero_pages);
+ZRAM_ATTR_RO(compr_data_size);
+
+static struct attribute *zram_disk_attrs[] = {
+ &dev_attr_disksize.attr,
+ &dev_attr_initstate.attr,
+ &dev_attr_reset.attr,
+ &dev_attr_num_reads.attr,
+ &dev_attr_num_writes.attr,
+ &dev_attr_failed_reads.attr,
+ &dev_attr_failed_writes.attr,
+ &dev_attr_compact.attr,
+ &dev_attr_invalid_io.attr,
+ &dev_attr_notify_free.attr,
+ &dev_attr_zero_pages.attr,
+ &dev_attr_orig_data_size.attr,
+ &dev_attr_compr_data_size.attr,
+ &dev_attr_mem_used_total.attr,
+ &dev_attr_mem_limit.attr,
+ &dev_attr_mem_used_max.attr,
+ &dev_attr_max_comp_streams.attr,
+ &dev_attr_comp_algorithm.attr,
+ &dev_attr_io_stat.attr,
+ &dev_attr_mm_stat.attr,
+ NULL,
+};
+
+static struct attribute_group zram_disk_attr_group = {
+ .attrs = zram_disk_attrs,
+};
+
+static int create_device(struct zram *zram, int device_id)
+{
+ struct request_queue *queue;
+ int ret = -ENOMEM;
+
+ init_rwsem(&zram->init_lock);
+
+ queue = blk_alloc_queue(GFP_KERNEL);
+ if (!queue) {
+ pr_err("Error allocating disk queue for device %d\n",
+ device_id);
+ goto out;
+ }
+
+ blk_queue_make_request(queue, zram_make_request);
+
+ /* gendisk structure */
+ zram->disk = alloc_disk(1);
+ if (!zram->disk) {
+ pr_warn("Error allocating disk structure for device %d\n",
+ device_id);
+ ret = -ENOMEM;
+ goto out_free_queue;
+ }
+
+ zram->disk->major = zram_major;
+ zram->disk->first_minor = device_id;
+ zram->disk->fops = &zram_devops;
+ zram->disk->queue = queue;
+ zram->disk->queue->queuedata = zram;
+ zram->disk->private_data = zram;
+ snprintf(zram->disk->disk_name, 16, "zram%d", device_id);
+
+ /* Actual capacity set using syfs (/sys/block/zram<id>/disksize */
+ set_capacity(zram->disk, 0);
+ /* zram devices sort of resembles non-rotational disks */
+ queue_flag_set_unlocked(QUEUE_FLAG_NONROT, zram->disk->queue);
+ queue_flag_clear_unlocked(QUEUE_FLAG_ADD_RANDOM, zram->disk->queue);
+ /*
+ * To ensure that we always get PAGE_SIZE aligned
+ * and n*PAGE_SIZED sized I/O requests.
+ */
+ blk_queue_physical_block_size(zram->disk->queue, PAGE_SIZE);
+ blk_queue_logical_block_size(zram->disk->queue,
+ ZRAM_LOGICAL_BLOCK_SIZE);
+ blk_queue_io_min(zram->disk->queue, PAGE_SIZE);
+ blk_queue_io_opt(zram->disk->queue, PAGE_SIZE);
+ zram->disk->queue->limits.discard_granularity = PAGE_SIZE;
+ zram->disk->queue->limits.max_discard_sectors = UINT_MAX;
+ /*
+ * zram_bio_discard() will clear all logical blocks if logical block
+ * size is identical with physical block size(PAGE_SIZE). But if it is
+ * different, we will skip discarding some parts of logical blocks in
+ * the part of the request range which isn't aligned to physical block
+ * size. So we can't ensure that all discarded logical blocks are
+ * zeroed.
+ */
+ if (ZRAM_LOGICAL_BLOCK_SIZE == PAGE_SIZE)
+ zram->disk->queue->limits.discard_zeroes_data = 1;
+ else
+ zram->disk->queue->limits.discard_zeroes_data = 0;
+ queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, zram->disk->queue);
+
+ add_disk(zram->disk);
+
+ ret = sysfs_create_group(&disk_to_dev(zram->disk)->kobj,
+ &zram_disk_attr_group);
+ if (ret < 0) {
+ pr_warn("Error creating sysfs group");
+ goto out_free_disk;
+ }
+ strlcpy(zram->compressor, default_compressor, sizeof(zram->compressor));
+ zram->meta = NULL;
+ zram->max_comp_streams = 1;
+ return 0;
+
+out_free_disk:
+ del_gendisk(zram->disk);
+ put_disk(zram->disk);
+out_free_queue:
+ blk_cleanup_queue(queue);
+out:
+ return ret;
+}
+
+static void destroy_devices(unsigned int nr)
+{
+ struct zram *zram;
+ unsigned int i;
+
+ for (i = 0; i < nr; i++) {
+ zram = &zram_devices[i];
+ /*
+ * Remove sysfs first, so no one will perform a disksize
+ * store while we destroy the devices
+ */
+ sysfs_remove_group(&disk_to_dev(zram->disk)->kobj,
+ &zram_disk_attr_group);
+
+ zram_reset_device(zram);
+
+ blk_cleanup_queue(zram->disk->queue);
+ del_gendisk(zram->disk);
+ put_disk(zram->disk);
+ }
+
+ kfree(zram_devices);
+ unregister_blkdev(zram_major, "zram");
+ pr_info("Destroyed %u device(s)\n", nr);
+}
+
+static int __init zram_init(void)
+{
+ int ret, dev_id;
+
+ if (num_devices > max_num_devices) {
+ pr_warn("Invalid value for num_devices: %u\n",
+ num_devices);
+ return -EINVAL;
+ }
+
+ zram_major = register_blkdev(0, "zram");
+ if (zram_major <= 0) {
+ pr_warn("Unable to get major number\n");
+ return -EBUSY;
+ }
+
+ /* Allocate the device array and initialize each one */
+ zram_devices = kzalloc(num_devices * sizeof(struct zram), GFP_KERNEL);
+ if (!zram_devices) {
+ unregister_blkdev(zram_major, "zram");
+ return -ENOMEM;
+ }
+
+ for (dev_id = 0; dev_id < num_devices; dev_id++) {
+ ret = create_device(&zram_devices[dev_id], dev_id);
+ if (ret)
+ goto out_error;
+ }
+
+ pr_info("Created %u device(s)\n", num_devices);
+ return 0;
+
+out_error:
+ destroy_devices(dev_id);
+ return ret;
+}
+
+static void __exit zram_exit(void)
+{
+ destroy_devices(num_devices);
+}
+
+module_init(zram_init);
+module_exit(zram_exit);
+
+module_param(num_devices, uint, 0);
+MODULE_PARM_DESC(num_devices, "Number of zram devices");
+
+MODULE_LICENSE("Dual BSD/GPL");
+MODULE_AUTHOR("Nitin Gupta <ngupta@vflare.org>");
+MODULE_DESCRIPTION("Compressed RAM Block Device");
--- /dev/null
+/*
+ * Compressed RAM block device
+ *
+ * Copyright (C) 2008, 2009, 2010 Nitin Gupta
+ * 2012, 2013 Minchan Kim
+ *
+ * This code is released using a dual license strategy: BSD/GPL
+ * You can choose the licence that better fits your requirements.
+ *
+ * Released under the terms of 3-clause BSD License
+ * Released under the terms of GNU General Public License Version 2.0
+ *
+ */
+
+#ifndef _ZRAM_DRV_H_
+#define _ZRAM_DRV_H_
+
+#include <linux/spinlock.h>
+#include <linux/zsmalloc.h>
+
+#include "zcomp.h"
+
+/*
+ * Some arbitrary value. This is just to catch
+ * invalid value for num_devices module parameter.
+ */
+static const unsigned max_num_devices = 32;
+
+/*-- Configurable parameters */
+
+/*
+ * Pages that compress to size greater than this are stored
+ * uncompressed in memory.
+ */
+static const size_t max_zpage_size = PAGE_SIZE / 4 * 3;
+
+/*
+ * NOTE: max_zpage_size must be less than or equal to:
+ * ZS_MAX_ALLOC_SIZE. Otherwise, zs_malloc() would
+ * always return failure.
+ */
+
+/*-- End of configurable params */
+
+#define SECTOR_SHIFT 9
+#define SECTORS_PER_PAGE_SHIFT (PAGE_SHIFT - SECTOR_SHIFT)
+#define SECTORS_PER_PAGE (1 << SECTORS_PER_PAGE_SHIFT)
+#define ZRAM_LOGICAL_BLOCK_SHIFT 12
+#define ZRAM_LOGICAL_BLOCK_SIZE (1 << ZRAM_LOGICAL_BLOCK_SHIFT)
+#define ZRAM_SECTOR_PER_LOGICAL_BLOCK \
+ (1 << (ZRAM_LOGICAL_BLOCK_SHIFT - SECTOR_SHIFT))
+
+
+/*
+ * The lower ZRAM_FLAG_SHIFT bits of table.value is for
+ * object size (excluding header), the higher bits is for
+ * zram_pageflags.
+ *
+ * zram is mainly used for memory efficiency so we want to keep memory
+ * footprint small so we can squeeze size and flags into a field.
+ * The lower ZRAM_FLAG_SHIFT bits is for object size (excluding header),
+ * the higher bits is for zram_pageflags.
+ */
+#define ZRAM_FLAG_SHIFT 24
+
+/* Flags for zram pages (table[page_no].value) */
+enum zram_pageflags {
+ /* Page consists entirely of zeros */
+ ZRAM_ZERO = ZRAM_FLAG_SHIFT,
+ ZRAM_ACCESS, /* page is now accessed */
+
+ __NR_ZRAM_PAGEFLAGS,
+};
+
+/*-- Data structures */
+
+/* Allocated for each disk page */
+struct zram_table_entry {
+ unsigned long handle;
+ unsigned long value;
+};
+
+struct zram_stats {
+ atomic64_t compr_data_size; /* compressed size of pages stored */
+ atomic64_t num_reads; /* failed + successful */
+ atomic64_t num_writes; /* --do-- */
+ atomic64_t num_migrated; /* no. of migrated object */
+ atomic64_t failed_reads; /* can happen when memory is too low */
+ atomic64_t failed_writes; /* can happen when memory is too low */
+ atomic64_t invalid_io; /* non-page-aligned I/O requests */
+ atomic64_t notify_free; /* no. of swap slot free notifications */
+ atomic64_t zero_pages; /* no. of zero filled pages */
+ atomic64_t pages_stored; /* no. of pages currently stored */
+ atomic_long_t max_used_pages; /* no. of maximum pages stored */
+};
+
+struct zram_meta {
+ struct zram_table_entry *table;
+ struct zs_pool *mem_pool;
+};
+
+struct zram {
+ struct zram_meta *meta;
+ struct zcomp *comp;
+ struct gendisk *disk;
+ /* Prevent concurrent execution of device init */
+ struct rw_semaphore init_lock;
+ /*
+ * the number of pages zram can consume for storing compressed data
+ */
+ unsigned long limit_pages;
+ int max_comp_streams;
+
+ struct zram_stats stats;
+ atomic_t refcount; /* refcount for zram_meta */
+ /* wait all IO under all of cpu are done */
+ wait_queue_head_t io_done;
+ /*
+ * This is the limit on amount of *uncompressed* worth of data
+ * we can store in a disk.
+ */
+ u64 disksize; /* bytes */
+ char compressor[10];
+};
+#endif
source "drivers/staging/iio/Kconfig"
-source "drivers/staging/zram/Kconfig"
-
source "drivers/staging/wlags49_h2/Kconfig"
source "drivers/staging/wlags49_h25/Kconfig"
obj-$(CONFIG_VME_BUS) += vme/
obj-$(CONFIG_DX_SEP) += sep/
obj-$(CONFIG_IIO) += iio/
-obj-$(CONFIG_ZRAM) += zram/
obj-$(CONFIG_WLAGS49_H2) += wlags49_h2/
obj-$(CONFIG_WLAGS49_H25) += wlags49_h25/
obj-$(CONFIG_FB_SM7XX) += sm7xxfb/
+++ /dev/null
-config ZRAM
- tristate "Compressed RAM block device support"
- depends on BLOCK && SYSFS && ZSMALLOC
- select LZO_COMPRESS
- select LZO_DECOMPRESS
- default n
- help
- Creates virtual block devices called /dev/zramX (X = 0, 1, ...).
- Pages written to these disks are compressed and stored in memory
- itself. These disks allow very fast I/O and compression provides
- good amounts of memory savings.
-
- It has several use cases, for example: /tmp storage, use as swap
- disks and maybe many more.
-
- See zram.txt for more information.
- Project home: <https://compcache.googlecode.com/>
-
-config ZRAM_DEBUG
- bool "Compressed RAM block device debug support"
- depends on ZRAM
- default n
- help
- This option adds additional debugging code to the compressed
- RAM block device driver.
+++ /dev/null
-zram-y := zram_drv.o zram_sysfs.o
-
-obj-$(CONFIG_ZRAM) += zram.o
+++ /dev/null
-zram: Compressed RAM based block devices
-----------------------------------------
-
-Project home: http://compcache.googlecode.com/
-
-* Introduction
-
-The zram module creates RAM based block devices named /dev/zram<id>
-(<id> = 0, 1, ...). Pages written to these disks are compressed and stored
-in memory itself. These disks allow very fast I/O and compression provides
-good amounts of memory savings. Some of the usecases include /tmp storage,
-use as swap disks, various caches under /var and maybe many more :)
-
-Statistics for individual zram devices are exported through sysfs nodes at
-/sys/block/zram<id>/
-
-* Usage
-
-Following shows a typical sequence of steps for using zram.
-
-1) Load Module:
- modprobe zram num_devices=4
- This creates 4 devices: /dev/zram{0,1,2,3}
- (num_devices parameter is optional. Default: 1)
-
-2) Set Disksize
- Set disk size by writing the value to sysfs node 'disksize'.
- The value can be either in bytes or you can use mem suffixes.
- Examples:
- # Initialize /dev/zram0 with 50MB disksize
- echo $((50*1024*1024)) > /sys/block/zram0/disksize
-
- # Using mem suffixes
- echo 256K > /sys/block/zram0/disksize
- echo 512M > /sys/block/zram0/disksize
- echo 1G > /sys/block/zram0/disksize
-
-3) Activate:
- mkswap /dev/zram0
- swapon /dev/zram0
-
- mkfs.ext4 /dev/zram1
- mount /dev/zram1 /tmp
-
-4) Stats:
- Per-device statistics are exported as various nodes under
- /sys/block/zram<id>/
- disksize
- num_reads
- num_writes
- invalid_io
- notify_free
- discard
- zero_pages
- orig_data_size
- compr_data_size
- mem_used_total
-
-5) Deactivate:
- swapoff /dev/zram0
- umount /dev/zram1
-
-6) Reset:
- Write any positive value to 'reset' sysfs node
- echo 1 > /sys/block/zram0/reset
- echo 1 > /sys/block/zram1/reset
-
- This frees all the memory allocated for the given device and
- resets the disksize to zero. You must set the disksize again
- before reusing the device.
-
-Please report any problems at:
- - Mailing list: linux-mm-cc at laptop dot org
- - Issue tracker: http://code.google.com/p/compcache/issues/list
-
-Nitin Gupta
-ngupta@vflare.org
+++ /dev/null
-/*
- * Compressed RAM block device
- *
- * Copyright (C) 2008, 2009, 2010 Nitin Gupta
- *
- * This code is released using a dual license strategy: BSD/GPL
- * You can choose the licence that better fits your requirements.
- *
- * Released under the terms of 3-clause BSD License
- * Released under the terms of GNU General Public License Version 2.0
- *
- * Project home: http://compcache.googlecode.com
- */
-
-#define KMSG_COMPONENT "zram"
-#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
-
-#ifdef CONFIG_ZRAM_DEBUG
-#define DEBUG
-#endif
-
-#include <linux/module.h>
-#include <linux/kernel.h>
-#include <linux/bio.h>
-#include <linux/bitops.h>
-#include <linux/blkdev.h>
-#include <linux/buffer_head.h>
-#include <linux/device.h>
-#include <linux/genhd.h>
-#include <linux/highmem.h>
-#include <linux/slab.h>
-#include <linux/lzo.h>
-#include <linux/string.h>
-#include <linux/vmalloc.h>
-
-#include "zram_drv.h"
-
-/* Globals */
-static int zram_major;
-struct zram *zram_devices;
-
-/* Module params (documentation at end) */
-static unsigned int num_devices = 1;
-
-static void zram_stat64_add(struct zram *zram, u64 *v, u64 inc)
-{
- spin_lock(&zram->stat64_lock);
- *v = *v + inc;
- spin_unlock(&zram->stat64_lock);
-}
-
-static void zram_stat64_sub(struct zram *zram, u64 *v, u64 dec)
-{
- spin_lock(&zram->stat64_lock);
- *v = *v - dec;
- spin_unlock(&zram->stat64_lock);
-}
-
-static void zram_stat64_inc(struct zram *zram, u64 *v)
-{
- zram_stat64_add(zram, v, 1);
-}
-
-static int zram_test_flag(struct zram_meta *meta, u32 index,
- enum zram_pageflags flag)
-{
- return meta->table[index].flags & BIT(flag);
-}
-
-static void zram_set_flag(struct zram_meta *meta, u32 index,
- enum zram_pageflags flag)
-{
- meta->table[index].flags |= BIT(flag);
-}
-
-static void zram_clear_flag(struct zram_meta *meta, u32 index,
- enum zram_pageflags flag)
-{
- meta->table[index].flags &= ~BIT(flag);
-}
-
-static int page_zero_filled(void *ptr)
-{
- unsigned int pos;
- unsigned long *page;
-
- page = (unsigned long *)ptr;
-
- for (pos = 0; pos != PAGE_SIZE / sizeof(*page); pos++) {
- if (page[pos])
- return 0;
- }
-
- return 1;
-}
-
-static void zram_free_page(struct zram *zram, size_t index)
-{
- struct zram_meta *meta = zram->meta;
- unsigned long handle = meta->table[index].handle;
- u16 size = meta->table[index].size;
-
- if (unlikely(!handle)) {
- /*
- * No memory is allocated for zero filled pages.
- * Simply clear zero page flag.
- */
- if (zram_test_flag(meta, index, ZRAM_ZERO)) {
- zram_clear_flag(meta, index, ZRAM_ZERO);
- zram->stats.pages_zero--;
- }
- return;
- }
-
- if (unlikely(size > max_zpage_size))
- zram->stats.bad_compress--;
-
- zs_free(meta->mem_pool, handle);
-
- if (size <= PAGE_SIZE / 2)
- zram->stats.good_compress--;
-
- zram_stat64_sub(zram, &zram->stats.compr_size,
- meta->table[index].size);
- zram->stats.pages_stored--;
-
- meta->table[index].handle = 0;
- meta->table[index].size = 0;
-}
-
-static void handle_zero_page(struct bio_vec *bvec)
-{
- struct page *page = bvec->bv_page;
- void *user_mem;
-
- user_mem = kmap_atomic(page);
- memset(user_mem + bvec->bv_offset, 0, bvec->bv_len);
- kunmap_atomic(user_mem);
-
- flush_dcache_page(page);
-}
-
-static inline int is_partial_io(struct bio_vec *bvec)
-{
- return bvec->bv_len != PAGE_SIZE;
-}
-
-static int zram_decompress_page(struct zram *zram, char *mem, u32 index)
-{
- int ret = LZO_E_OK;
- size_t clen = PAGE_SIZE;
- unsigned char *cmem;
- struct zram_meta *meta = zram->meta;
- unsigned long handle = meta->table[index].handle;
-
- if (!handle || zram_test_flag(meta, index, ZRAM_ZERO)) {
- memset(mem, 0, PAGE_SIZE);
- return 0;
- }
-
- cmem = zs_map_object(meta->mem_pool, handle, ZS_MM_RO);
- if (meta->table[index].size == PAGE_SIZE)
- memcpy(mem, cmem, PAGE_SIZE);
- else
- ret = lzo1x_decompress_safe(cmem, meta->table[index].size,
- mem, &clen);
- zs_unmap_object(meta->mem_pool, handle);
-
- /* Should NEVER happen. Return bio error if it does. */
- if (unlikely(ret != LZO_E_OK)) {
- pr_err("Decompression failed! err=%d, page=%u\n", ret, index);
- zram_stat64_inc(zram, &zram->stats.failed_reads);
- return ret;
- }
-
- return 0;
-}
-
-static int zram_bvec_read(struct zram *zram, struct bio_vec *bvec,
- u32 index, int offset, struct bio *bio)
-{
- int ret;
- struct page *page;
- unsigned char *user_mem, *uncmem = NULL;
- struct zram_meta *meta = zram->meta;
- page = bvec->bv_page;
-
- if (unlikely(!meta->table[index].handle) ||
- zram_test_flag(meta, index, ZRAM_ZERO)) {
- handle_zero_page(bvec);
- return 0;
- }
-
- if (is_partial_io(bvec))
- /* Use a temporary buffer to decompress the page */
- uncmem = kmalloc(PAGE_SIZE, GFP_NOIO);
-
- user_mem = kmap_atomic(page);
- if (!is_partial_io(bvec))
- uncmem = user_mem;
-
- if (!uncmem) {
- pr_info("Unable to allocate temp memory\n");
- ret = -ENOMEM;
- goto out_cleanup;
- }
-
- ret = zram_decompress_page(zram, uncmem, index);
- /* Should NEVER happen. Return bio error if it does. */
- if (unlikely(ret != LZO_E_OK))
- goto out_cleanup;
-
- if (is_partial_io(bvec))
- memcpy(user_mem + bvec->bv_offset, uncmem + offset,
- bvec->bv_len);
-
- flush_dcache_page(page);
- ret = 0;
-out_cleanup:
- kunmap_atomic(user_mem);
- if (is_partial_io(bvec))
- kfree(uncmem);
- return ret;
-}
-
-static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index,
- int offset)
-{
- int ret = 0;
- size_t clen;
- unsigned long handle;
- struct page *page;
- unsigned char *user_mem, *cmem, *src, *uncmem = NULL;
- struct zram_meta *meta = zram->meta;
-
- page = bvec->bv_page;
- src = meta->compress_buffer;
-
- if (is_partial_io(bvec)) {
- /*
- * This is a partial IO. We need to read the full page
- * before to write the changes.
- */
- uncmem = kmalloc(PAGE_SIZE, GFP_NOIO);
- if (!uncmem) {
- ret = -ENOMEM;
- goto out;
- }
- ret = zram_decompress_page(zram, uncmem, index);
- if (ret)
- goto out;
- }
-
- /*
- * System overwrites unused sectors. Free memory associated
- * with this sector now.
- */
- if (meta->table[index].handle ||
- zram_test_flag(meta, index, ZRAM_ZERO))
- zram_free_page(zram, index);
-
- user_mem = kmap_atomic(page);
-
- if (is_partial_io(bvec)) {
- memcpy(uncmem + offset, user_mem + bvec->bv_offset,
- bvec->bv_len);
- kunmap_atomic(user_mem);
- user_mem = NULL;
- } else {
- uncmem = user_mem;
- }
-
- if (page_zero_filled(uncmem)) {
- kunmap_atomic(user_mem);
- zram->stats.pages_zero++;
- zram_set_flag(meta, index, ZRAM_ZERO);
- ret = 0;
- goto out;
- }
-
- ret = lzo1x_1_compress(uncmem, PAGE_SIZE, src, &clen,
- meta->compress_workmem);
-
- if (!is_partial_io(bvec)) {
- kunmap_atomic(user_mem);
- user_mem = NULL;
- uncmem = NULL;
- }
-
- if (unlikely(ret != LZO_E_OK)) {
- pr_err("Compression failed! err=%d\n", ret);
- goto out;
- }
-
- if (unlikely(clen > max_zpage_size)) {
- zram->stats.bad_compress++;
- clen = PAGE_SIZE;
- src = NULL;
- if (is_partial_io(bvec))
- src = uncmem;
- }
-
- handle = zs_malloc(meta->mem_pool, clen);
- if (!handle) {
- pr_info("Error allocating memory for compressed "
- "page: %u, size=%zu\n", index, clen);
- ret = -ENOMEM;
- goto out;
- }
- cmem = zs_map_object(meta->mem_pool, handle, ZS_MM_WO);
-
- if ((clen == PAGE_SIZE) && !is_partial_io(bvec))
- src = kmap_atomic(page);
- memcpy(cmem, src, clen);
- if ((clen == PAGE_SIZE) && !is_partial_io(bvec))
- kunmap_atomic(src);
-
- zs_unmap_object(meta->mem_pool, handle);
-
- meta->table[index].handle = handle;
- meta->table[index].size = clen;
-
- /* Update stats */
- zram_stat64_add(zram, &zram->stats.compr_size, clen);
- zram->stats.pages_stored++;
- if (clen <= PAGE_SIZE / 2)
- zram->stats.good_compress++;
-
-out:
- if (is_partial_io(bvec))
- kfree(uncmem);
-
- if (ret)
- zram_stat64_inc(zram, &zram->stats.failed_writes);
- return ret;
-}
-
-static int zram_bvec_rw(struct zram *zram, struct bio_vec *bvec, u32 index,
- int offset, struct bio *bio, int rw)
-{
- int ret;
-
- if (rw == READ) {
- down_read(&zram->lock);
- ret = zram_bvec_read(zram, bvec, index, offset, bio);
- up_read(&zram->lock);
- } else {
- down_write(&zram->lock);
- ret = zram_bvec_write(zram, bvec, index, offset);
- up_write(&zram->lock);
- }
-
- return ret;
-}
-
-static void update_position(u32 *index, int *offset, struct bio_vec *bvec)
-{
- if (*offset + bvec->bv_len >= PAGE_SIZE)
- (*index)++;
- *offset = (*offset + bvec->bv_len) % PAGE_SIZE;
-}
-
-static void __zram_make_request(struct zram *zram, struct bio *bio, int rw)
-{
- int i, offset;
- u32 index;
- struct bio_vec *bvec;
-
- switch (rw) {
- case READ:
- zram_stat64_inc(zram, &zram->stats.num_reads);
- break;
- case WRITE:
- zram_stat64_inc(zram, &zram->stats.num_writes);
- break;
- }
-
- index = bio->bi_sector >> SECTORS_PER_PAGE_SHIFT;
- offset = (bio->bi_sector & (SECTORS_PER_PAGE - 1)) << SECTOR_SHIFT;
-
- bio_for_each_segment(bvec, bio, i) {
- int max_transfer_size = PAGE_SIZE - offset;
-
- if (bvec->bv_len > max_transfer_size) {
- /*
- * zram_bvec_rw() can only make operation on a single
- * zram page. Split the bio vector.
- */
- struct bio_vec bv;
-
- bv.bv_page = bvec->bv_page;
- bv.bv_len = max_transfer_size;
- bv.bv_offset = bvec->bv_offset;
-
- if (zram_bvec_rw(zram, &bv, index, offset, bio, rw) < 0)
- goto out;
-
- bv.bv_len = bvec->bv_len - max_transfer_size;
- bv.bv_offset += max_transfer_size;
- if (zram_bvec_rw(zram, &bv, index+1, 0, bio, rw) < 0)
- goto out;
- } else
- if (zram_bvec_rw(zram, bvec, index, offset, bio, rw)
- < 0)
- goto out;
-
- update_position(&index, &offset, bvec);
- }
-
- set_bit(BIO_UPTODATE, &bio->bi_flags);
- bio_endio(bio, 0);
- return;
-
-out:
- bio_io_error(bio);
-}
-
-/*
- * Check if request is within bounds and aligned on zram logical blocks.
- */
-static inline int valid_io_request(struct zram *zram, struct bio *bio)
-{
- u64 start, end, bound;
-
- /* unaligned request */
- if (unlikely(bio->bi_sector & (ZRAM_SECTOR_PER_LOGICAL_BLOCK - 1)))
- return 0;
- if (unlikely(bio->bi_size & (ZRAM_LOGICAL_BLOCK_SIZE - 1)))
- return 0;
-
- start = bio->bi_sector;
- end = start + (bio->bi_size >> SECTOR_SHIFT);
- bound = zram->disksize >> SECTOR_SHIFT;
- /* out of range range */
- if (unlikely(start >= bound || end > bound || start > end))
- return 0;
-
- /* I/O request is valid */
- return 1;
-}
-
-/*
- * Handler function for all zram I/O requests.
- */
-static void zram_make_request(struct request_queue *queue, struct bio *bio)
-{
- struct zram *zram = queue->queuedata;
-
- down_read(&zram->init_lock);
- if (unlikely(!zram->init_done))
- goto error;
-
- if (!valid_io_request(zram, bio)) {
- zram_stat64_inc(zram, &zram->stats.invalid_io);
- goto error;
- }
-
- __zram_make_request(zram, bio, bio_data_dir(bio));
- up_read(&zram->init_lock);
-
- return;
-
-error:
- up_read(&zram->init_lock);
- bio_io_error(bio);
-}
-
-static void __zram_reset_device(struct zram *zram)
-{
- size_t index;
- struct zram_meta *meta;
-
- if (!zram->init_done)
- return;
-
- meta = zram->meta;
- zram->init_done = 0;
-
- /* Free all pages that are still in this zram device */
- for (index = 0; index < zram->disksize >> PAGE_SHIFT; index++) {
- unsigned long handle = meta->table[index].handle;
- if (!handle)
- continue;
-
- zs_free(meta->mem_pool, handle);
- }
-
- zram_meta_free(zram->meta);
- zram->meta = NULL;
- /* Reset stats */
- memset(&zram->stats, 0, sizeof(zram->stats));
-
- zram->disksize = 0;
- set_capacity(zram->disk, 0);
-}
-
-void zram_reset_device(struct zram *zram)
-{
- down_write(&zram->init_lock);
- __zram_reset_device(zram);
- up_write(&zram->init_lock);
-}
-
-void zram_meta_free(struct zram_meta *meta)
-{
- zs_destroy_pool(meta->mem_pool);
- kfree(meta->compress_workmem);
- free_pages((unsigned long)meta->compress_buffer, 1);
- vfree(meta->table);
- kfree(meta);
-}
-
-struct zram_meta *zram_meta_alloc(u64 disksize)
-{
- size_t num_pages;
- struct zram_meta *meta = kmalloc(sizeof(*meta), GFP_KERNEL);
- if (!meta)
- goto out;
-
- meta->compress_workmem = kzalloc(LZO1X_MEM_COMPRESS, GFP_KERNEL);
- if (!meta->compress_workmem)
- goto free_meta;
-
- meta->compress_buffer =
- (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, 1);
- if (!meta->compress_buffer) {
- pr_err("Error allocating compressor buffer space\n");
- goto free_workmem;
- }
-
- num_pages = disksize >> PAGE_SHIFT;
- meta->table = vzalloc(num_pages * sizeof(*meta->table));
- if (!meta->table) {
- pr_err("Error allocating zram address table\n");
- goto free_buffer;
- }
-
- meta->mem_pool = zs_create_pool(GFP_NOIO | __GFP_HIGHMEM, NULL);
- if (!meta->mem_pool) {
- pr_err("Error creating memory pool\n");
- goto free_table;
- }
-
- return meta;
-
-free_table:
- vfree(meta->table);
-free_buffer:
- free_pages((unsigned long)meta->compress_buffer, 1);
-free_workmem:
- kfree(meta->compress_workmem);
-free_meta:
- kfree(meta);
- meta = NULL;
-out:
- return meta;
-}
-
-void zram_init_device(struct zram *zram, struct zram_meta *meta)
-{
- if (zram->disksize > 2 * (totalram_pages << PAGE_SHIFT)) {
- pr_info(
- "There is little point creating a zram of greater than "
- "twice the size of memory since we expect a 2:1 compression "
- "ratio. Note that zram uses about 0.1%% of the size of "
- "the disk when not in use so a huge zram is "
- "wasteful.\n"
- "\tMemory Size: %lu kB\n"
- "\tSize you selected: %llu kB\n"
- "Continuing anyway ...\n",
- (totalram_pages << PAGE_SHIFT) >> 10, zram->disksize >> 10
- );
- }
-
- /* zram devices sort of resembles non-rotational disks */
- queue_flag_set_unlocked(QUEUE_FLAG_NONROT, zram->disk->queue);
-
- zram->meta = meta;
- zram->init_done = 1;
-
- pr_debug("Initialization done!\n");
-}
-
-static void zram_slot_free_notify(struct block_device *bdev,
- unsigned long index)
-{
- struct zram *zram;
-
- zram = bdev->bd_disk->private_data;
- down_write(&zram->lock);
- zram_free_page(zram, index);
- up_write(&zram->lock);
- zram_stat64_inc(zram, &zram->stats.notify_free);
-}
-
-static const struct block_device_operations zram_devops = {
- .swap_slot_free_notify = zram_slot_free_notify,
- .owner = THIS_MODULE
-};
-
-static int create_device(struct zram *zram, int device_id)
-{
- int ret = -ENOMEM;
-
- init_rwsem(&zram->lock);
- init_rwsem(&zram->init_lock);
- spin_lock_init(&zram->stat64_lock);
-
- zram->queue = blk_alloc_queue(GFP_KERNEL);
- if (!zram->queue) {
- pr_err("Error allocating disk queue for device %d\n",
- device_id);
- goto out;
- }
-
- blk_queue_make_request(zram->queue, zram_make_request);
- zram->queue->queuedata = zram;
-
- /* gendisk structure */
- zram->disk = alloc_disk(1);
- if (!zram->disk) {
- pr_warn("Error allocating disk structure for device %d\n",
- device_id);
- goto out_free_queue;
- }
-
- zram->disk->major = zram_major;
- zram->disk->first_minor = device_id;
- zram->disk->fops = &zram_devops;
- zram->disk->queue = zram->queue;
- zram->disk->private_data = zram;
- snprintf(zram->disk->disk_name, 16, "zram%d", device_id);
-
- /* Actual capacity set using syfs (/sys/block/zram<id>/disksize */
- set_capacity(zram->disk, 0);
-
- /*
- * To ensure that we always get PAGE_SIZE aligned
- * and n*PAGE_SIZED sized I/O requests.
- */
- blk_queue_physical_block_size(zram->disk->queue, PAGE_SIZE);
- blk_queue_logical_block_size(zram->disk->queue,
- ZRAM_LOGICAL_BLOCK_SIZE);
- blk_queue_io_min(zram->disk->queue, PAGE_SIZE);
- blk_queue_io_opt(zram->disk->queue, PAGE_SIZE);
-
- add_disk(zram->disk);
-
- ret = sysfs_create_group(&disk_to_dev(zram->disk)->kobj,
- &zram_disk_attr_group);
- if (ret < 0) {
- pr_warn("Error creating sysfs group");
- goto out_free_disk;
- }
-
- zram->init_done = 0;
- return 0;
-
-out_free_disk:
- del_gendisk(zram->disk);
- put_disk(zram->disk);
-out_free_queue:
- blk_cleanup_queue(zram->queue);
-out:
- return ret;
-}
-
-static void destroy_device(struct zram *zram)
-{
- sysfs_remove_group(&disk_to_dev(zram->disk)->kobj,
- &zram_disk_attr_group);
-
- if (zram->disk) {
- del_gendisk(zram->disk);
- put_disk(zram->disk);
- }
-
- if (zram->queue)
- blk_cleanup_queue(zram->queue);
-}
-
-unsigned int zram_get_num_devices(void)
-{
- return num_devices;
-}
-
-static int __init zram_init(void)
-{
- int ret, dev_id;
-
- if (num_devices > max_num_devices) {
- pr_warn("Invalid value for num_devices: %u\n",
- num_devices);
- ret = -EINVAL;
- goto out;
- }
-
- zram_major = register_blkdev(0, "zram");
- if (zram_major <= 0) {
- pr_warn("Unable to get major number\n");
- ret = -EBUSY;
- goto out;
- }
-
- /* Allocate the device array and initialize each one */
- zram_devices = kzalloc(num_devices * sizeof(struct zram), GFP_KERNEL);
- if (!zram_devices) {
- ret = -ENOMEM;
- goto unregister;
- }
-
- for (dev_id = 0; dev_id < num_devices; dev_id++) {
- ret = create_device(&zram_devices[dev_id], dev_id);
- if (ret)
- goto free_devices;
- }
-
- pr_info("Created %u device(s) ...\n", num_devices);
-
- return 0;
-
-free_devices:
- while (dev_id)
- destroy_device(&zram_devices[--dev_id]);
- kfree(zram_devices);
-unregister:
- unregister_blkdev(zram_major, "zram");
-out:
- return ret;
-}
-
-static void __exit zram_exit(void)
-{
- int i;
- struct zram *zram;
-
- for (i = 0; i < num_devices; i++) {
- zram = &zram_devices[i];
-
- get_disk(zram->disk);
- destroy_device(zram);
- zram_reset_device(zram);
- put_disk(zram->disk);
- }
-
- unregister_blkdev(zram_major, "zram");
-
- kfree(zram_devices);
- pr_debug("Cleanup done!\n");
-}
-
-module_param(num_devices, uint, 0);
-MODULE_PARM_DESC(num_devices, "Number of zram devices");
-
-module_init(zram_init);
-module_exit(zram_exit);
-
-MODULE_LICENSE("Dual BSD/GPL");
-MODULE_AUTHOR("Nitin Gupta <ngupta@vflare.org>");
-MODULE_DESCRIPTION("Compressed RAM Block Device");
+++ /dev/null
-/*
- * Compressed RAM block device
- *
- * Copyright (C) 2008, 2009, 2010 Nitin Gupta
- *
- * This code is released using a dual license strategy: BSD/GPL
- * You can choose the licence that better fits your requirements.
- *
- * Released under the terms of 3-clause BSD License
- * Released under the terms of GNU General Public License Version 2.0
- *
- * Project home: http://compcache.googlecode.com
- */
-
-#ifndef _ZRAM_DRV_H_
-#define _ZRAM_DRV_H_
-
-#include <linux/spinlock.h>
-#include <linux/mutex.h>
-#include <linux/zsmalloc.h>
-
-/*
- * Some arbitrary value. This is just to catch
- * invalid value for num_devices module parameter.
- */
-static const unsigned max_num_devices = 32;
-
-/*-- Configurable parameters */
-
-/*
- * Pages that compress to size greater than this are stored
- * uncompressed in memory.
- */
-static const size_t max_zpage_size = PAGE_SIZE / 4 * 3;
-
-/*
- * NOTE: max_zpage_size must be less than or equal to:
- * ZS_MAX_ALLOC_SIZE. Otherwise, zs_malloc() would
- * always return failure.
- */
-
-/*-- End of configurable params */
-
-#define SECTOR_SHIFT 9
-#define SECTOR_SIZE (1 << SECTOR_SHIFT)
-#define SECTORS_PER_PAGE_SHIFT (PAGE_SHIFT - SECTOR_SHIFT)
-#define SECTORS_PER_PAGE (1 << SECTORS_PER_PAGE_SHIFT)
-#define ZRAM_LOGICAL_BLOCK_SHIFT 12
-#define ZRAM_LOGICAL_BLOCK_SIZE (1 << ZRAM_LOGICAL_BLOCK_SHIFT)
-#define ZRAM_SECTOR_PER_LOGICAL_BLOCK \
- (1 << (ZRAM_LOGICAL_BLOCK_SHIFT - SECTOR_SHIFT))
-
-/* Flags for zram pages (table[page_no].flags) */
-enum zram_pageflags {
- /* Page consists entirely of zeros */
- ZRAM_ZERO,
-
- __NR_ZRAM_PAGEFLAGS,
-};
-
-/*-- Data structures */
-
-/* Allocated for each disk page */
-struct table {
- unsigned long handle;
- u16 size; /* object size (excluding header) */
- u8 count; /* object ref count (not yet used) */
- u8 flags;
-} __aligned(4);
-
-struct zram_stats {
- u64 compr_size; /* compressed size of pages stored */
- u64 num_reads; /* failed + successful */
- u64 num_writes; /* --do-- */
- u64 failed_reads; /* should NEVER! happen */
- u64 failed_writes; /* can happen when memory is too low */
- u64 invalid_io; /* non-page-aligned I/O requests */
- u64 notify_free; /* no. of swap slot free notifications */
- u32 pages_zero; /* no. of zero filled pages */
- u32 pages_stored; /* no. of pages currently stored */
- u32 good_compress; /* % of pages with compression ratio<=50% */
- u32 bad_compress; /* % of pages with compression ratio>=75% */
-};
-
-struct zram_meta {
- void *compress_workmem;
- void *compress_buffer;
- struct table *table;
- struct zs_pool *mem_pool;
-};
-
-struct zram {
- struct zram_meta *meta;
- spinlock_t stat64_lock; /* protect 64-bit stats */
- struct rw_semaphore lock; /* protect compression buffers, table,
- * 32bit stat counters against concurrent
- * notifications, reads and writes */
- struct request_queue *queue;
- struct gendisk *disk;
- int init_done;
- /* Prevent concurrent execution of device init, reset and R/W request */
- struct rw_semaphore init_lock;
- /*
- * This is the limit on amount of *uncompressed* worth of data
- * we can store in a disk.
- */
- u64 disksize; /* bytes */
-
- struct zram_stats stats;
-};
-
-extern struct zram *zram_devices;
-unsigned int zram_get_num_devices(void);
-#ifdef CONFIG_SYSFS
-extern struct attribute_group zram_disk_attr_group;
-#endif
-
-extern void zram_reset_device(struct zram *zram);
-extern struct zram_meta *zram_meta_alloc(u64 disksize);
-extern void zram_meta_free(struct zram_meta *meta);
-extern void zram_init_device(struct zram *zram, struct zram_meta *meta);
-
-#endif
}
}
+void generic_start_io_acct(int rw, unsigned long sectors,
+ struct hd_struct *part)
+{
+ int cpu = part_stat_lock();
+
+ part_round_stats(cpu, part);
+ part_stat_inc(cpu, part, ios[rw]);
+ part_stat_add(cpu, part, sectors[rw], sectors);
+ part_inc_in_flight(part, rw);
+
+ part_stat_unlock();
+}
+EXPORT_SYMBOL(generic_start_io_acct);
+
+void generic_end_io_acct(int rw, struct hd_struct *part,
+ unsigned long start_time)
+{
+ unsigned long duration = jiffies - start_time;
+ int cpu = part_stat_lock();
+
+ part_stat_add(cpu, part, ticks[rw], duration);
+ part_round_stats(cpu, part);
+ part_dec_in_flight(part, rw);
+
+ part_stat_unlock();
+}
+EXPORT_SYMBOL(generic_end_io_acct);
+
#if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
void bio_flush_dcache_pages(struct bio *bi)
{
extern void bio_set_pages_dirty(struct bio *bio);
extern void bio_check_pages_dirty(struct bio *bio);
+void generic_start_io_acct(int rw, unsigned long sectors,
+ struct hd_struct *part);
+void generic_end_io_acct(int rw, struct hd_struct *part,
+ unsigned long start_time);
+
#ifndef ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
# error "You should define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE for your platform"
#endif
#define DEVICE_ATTR(_name, _mode, _show, _store) \
struct device_attribute dev_attr_##_name = __ATTR(_name, _mode, _show, _store)
+#define DEVICE_ATTR_RW(_name) \
+ struct device_attribute dev_attr_##_name = __ATTR_RW(_name)
+#define DEVICE_ATTR_RO(_name) \
+ struct device_attribute dev_attr_##_name = __ATTR_RO(_name)
+#define DEVICE_ATTR_WO(_name) \
+ struct device_attribute dev_attr_##_name = __ATTR_WO(_name)
#define DEVICE_ULONG_ATTR(_name, _mode, _var) \
struct dev_ext_attribute dev_attr_##_name = \
{ __ATTR(_name, _mode, device_show_ulong, device_store_ulong), &(_var) }
.show = _name##_show, \
}
+
+#define __ATTR_WO(_name) { \
+ .attr = { .name = __stringify(_name), .mode = S_IWUSR }, \
+ .store = _name##_store, \
+}
+
+#define __ATTR_RW(_name) __ATTR(_name, (S_IWUSR | S_IRUGO), \
+ _name##_show, _name##_store)
+
#define __ATTR_NULL { .attr = { .name = NULL } }
#ifdef CONFIG_DEBUG_LOCK_ALLOC
bdi_cap_stable_pages_required(bdi) ? 1 : 0);
}
-#define __ATTR_RW(attr) __ATTR(attr, 0644, attr##_show, attr##_store)
-
static struct device_attribute bdi_dev_attrs[] = {
__ATTR_RW(read_ahead_kb),
__ATTR_RW(min_ratio),
static inline void *__zs_map_object(struct mapping_area *area,
struct page *pages[2], int off, int size)
{
- BUG_ON(map_vm_area(area->vm, PAGE_KERNEL, &pages));
+ BUG_ON(map_vm_area(area->vm, PAGE_KERNEL, pages));
area->vm_addr = area->vm->addr;
return area->vm_addr + off;
}
projects / GitHub / LineageOS / android_kernel_samsung_universal7580.git / commitdiff