drm/ttm: Use private locks for the default bo range manager

Searching for a free block in the range manager may in some situations be a
lenghty operation, and we want to avoid holding the global lru lock
during that time. Instead use a per-manager spinlock.

This leaves the global lru lock for quick lru list and swap list manipulation
only, including list manipulation associated with reserving buffer objects.

Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

diff --git a/drivers/gpu/drm/ttm/ttm_bo_manager.c b/drivers/gpu/drm/ttm/ttm_bo_manager.c
index 7410c190c8911a9342ba57ea616d77a722061312..038e947d00f986ef987ef914fd8432f2202c25f3 100644 (file)
--- a/drivers/gpu/drm/ttm/ttm_bo_manager.c
+++ b/drivers/gpu/drm/ttm/ttm_bo_manager.c
@@ -1,6 +1,6 @@
 /**************************************************************************
  *
- * Copyright (c) 2007-2009 VMware, Inc., Palo Alto, CA., USA
+ * Copyright (c) 2007-2010 VMware, Inc., Palo Alto, CA., USA
  * All Rights Reserved.
  *
  * Permission is hereby granted, free of charge, to any person obtaining a
@@ -31,20 +31,29 @@
 #include "ttm/ttm_module.h"
 #include "ttm/ttm_bo_driver.h"
 #include "ttm/ttm_placement.h"
-#include <linux/jiffies.h>
+#include "drm_mm.h"
 #include <linux/slab.h>
-#include <linux/sched.h>
-#include <linux/mm.h>
-#include <linux/file.h>
+#include <linux/spinlock.h>
 #include <linux/module.h>
 
+/**
+ * Currently we use a spinlock for the lock, but a mutex *may* be
+ * more appropriate to reduce scheduling latency if the range manager
+ * ends up with very fragmented allocation patterns.
+ */
+
+struct ttm_range_manager {
+       struct drm_mm mm;
+       spinlock_t lock;
+};
+
 static int ttm_bo_man_get_node(struct ttm_mem_type_manager *man,
                               struct ttm_buffer_object *bo,
                               struct ttm_placement *placement,
                               struct ttm_mem_reg *mem)
 {
-       struct ttm_bo_global *glob = man->bdev->glob;
-       struct drm_mm *mm = man->priv;
+       struct ttm_range_manager *rman = (struct ttm_range_manager *) man->priv;
+       struct drm_mm *mm = &rman->mm;
        struct drm_mm_node *node = NULL;
        unsigned long lpfn;
        int ret;
@@ -57,19 +66,19 @@ static int ttm_bo_man_get_node(struct ttm_mem_type_manager *man,
                if (unlikely(ret))
                        return ret;
 
-               spin_lock(&glob->lru_lock);
+               spin_lock(&rman->lock);
                node = drm_mm_search_free_in_range(mm,
                                        mem->num_pages, mem->page_alignment,
                                        placement->fpfn, lpfn, 1);
                if (unlikely(node == NULL)) {
-                       spin_unlock(&glob->lru_lock);
+                       spin_unlock(&rman->lock);
                        return 0;
                }
                node = drm_mm_get_block_atomic_range(node, mem->num_pages,
-                                                       mem->page_alignment,
-                                                       placement->fpfn,
-                                                       lpfn);
-               spin_unlock(&glob->lru_lock);
+                                                    mem->page_alignment,
+                                                    placement->fpfn,
+                                                    lpfn);
+               spin_unlock(&rman->lock);
        } while (node == NULL);
 
        mem->mm_node = node;
@@ -80,12 +89,12 @@ static int ttm_bo_man_get_node(struct ttm_mem_type_manager *man,
 static void ttm_bo_man_put_node(struct ttm_mem_type_manager *man,
                                struct ttm_mem_reg *mem)
 {
-       struct ttm_bo_global *glob = man->bdev->glob;
+       struct ttm_range_manager *rman = (struct ttm_range_manager *) man->priv;
 
        if (mem->mm_node) {
-               spin_lock(&glob->lru_lock);
+               spin_lock(&rman->lock);
                drm_mm_put_block(mem->mm_node);
-               spin_unlock(&glob->lru_lock);
+               spin_unlock(&rman->lock);
                mem->mm_node = NULL;
        }
 }
@@ -93,49 +102,49 @@ static void ttm_bo_man_put_node(struct ttm_mem_type_manager *man,
 static int ttm_bo_man_init(struct ttm_mem_type_manager *man,
                           unsigned long p_size)
 {
-       struct drm_mm *mm;
+       struct ttm_range_manager *rman;
        int ret;
 
-       mm = kzalloc(sizeof(*mm), GFP_KERNEL);
-       if (!mm)
+       rman = kzalloc(sizeof(*rman), GFP_KERNEL);
+       if (!rman)
                return -ENOMEM;
 
-       ret = drm_mm_init(mm, 0, p_size);
+       ret = drm_mm_init(&rman->mm, 0, p_size);
        if (ret) {
-               kfree(mm);
+               kfree(rman);
                return ret;
        }
 
-       man->priv = mm;
+       spin_lock_init(&rman->lock);
+       man->priv = rman;
        return 0;
 }
 
 static int ttm_bo_man_takedown(struct ttm_mem_type_manager *man)
 {
-       struct ttm_bo_global *glob = man->bdev->glob;
-       struct drm_mm *mm = man->priv;
-       int ret = 0;
+       struct ttm_range_manager *rman = (struct ttm_range_manager *) man->priv;
+       struct drm_mm *mm = &rman->mm;
 
-       spin_lock(&glob->lru_lock);
+       spin_lock(&rman->lock);
        if (drm_mm_clean(mm)) {
                drm_mm_takedown(mm);
-               kfree(mm);
+               spin_unlock(&rman->lock);
+               kfree(rman);
                man->priv = NULL;
-       } else
-               ret = -EBUSY;
-       spin_unlock(&glob->lru_lock);
-       return ret;
+               return 0;
+       }
+       spin_unlock(&rman->lock);
+       return -EBUSY;
 }
 
 static void ttm_bo_man_debug(struct ttm_mem_type_manager *man,
                             const char *prefix)
 {
-       struct ttm_bo_global *glob = man->bdev->glob;
-       struct drm_mm *mm = man->priv;
+       struct ttm_range_manager *rman = (struct ttm_range_manager *) man->priv;
 
-       spin_lock(&glob->lru_lock);
-       drm_mm_debug_table(mm, prefix);
-       spin_unlock(&glob->lru_lock);
+       spin_lock(&rman->lock);
+       drm_mm_debug_table(&rman->mm, prefix);
+       spin_unlock(&rman->lock);
 }
 
 const struct ttm_mem_type_manager_func ttm_bo_manager_func = {