From: Jing Zhang <zj.barak@xxxxxxxxx>
Date: Sun Mar 28 17:09:33 2010
rb_tree cache is added to struct ext4_group_info at minor cost.
Cc: Theodore Ts'o <tytso@xxxxxxx>
Cc: Andreas Dilger <adilger@xxxxxxx>
Cc: Dave Kleikamp <shaggy@xxxxxxxxxxxxxxxxxx>
Cc: "Aneesh Kumar K. V" <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Jing Zhang <zj.barak@xxxxxxxxx>
---
--- linux-2.6.32/fs/ext4/ext4.h 2009-12-03 11:51:22.000000000 +0800
+++ ext4_mm_leak/ext4-12.h 2010-03-28 16:47:56.000000000 +0800
@@ -1622,6 +1622,7 @@ static inline void ext4_update_i_disksiz
struct ext4_group_info {
unsigned long bb_state;
struct rb_root bb_free_root;
+ struct rb_node *bb_free_cache;
ext4_grpblk_t bb_first_free; /* first free block */
ext4_grpblk_t bb_free; /* total free blocks */
ext4_grpblk_t bb_fragments; /* nr of freespace fragments */
--- linux-2.6.32/fs/ext4/mballoc.c 2009-12-03 11:51:22.000000000 +0800
+++ ext4_mm_leak/mballoc-12.c 2010-03-28 16:43:08.000000000 +0800
@@ -2548,6 +2548,8 @@ static void release_blocks_on_commit(jou
count2++;
ext4_lock_group(sb, entry->group);
/* Take it out of per group rb tree */
+ if (db->bb_free_cache == &entry->node)
+ db->bb_free_cache = rb_next(&entry->node);
rb_erase(&entry->node, &(db->bb_free_root));
mb_free_blocks(NULL, &e4b, entry->start_blk, entry->count);
@@ -3188,7 +3190,10 @@ static void ext4_mb_generate_from_freeli
struct ext4_free_data *entry;
grp = ext4_get_group_info(sb, group);
- n = rb_first(&(grp->bb_free_root));
+ if (grp->bb_free_cache)
+ n = grp->bb_free_cache;
+ else
+ n = rb_first(&(grp->bb_free_root));
while (n) {
entry = rb_entry(n, struct ext4_free_data, node);
@@ -4353,6 +4358,7 @@ ext4_mb_free_metadata(handle_t *handle,
struct ext4_sb_info *sbi = EXT4_SB(sb);
struct rb_node **n = &db->bb_free_root.rb_node, *node;
struct rb_node *parent = NULL, *new_node;
+ int left = 1;
BUG_ON(!ext4_handle_valid(handle));
BUG_ON(e4b->bd_bitmap_page == NULL);
@@ -4369,6 +4375,8 @@ ext4_mb_free_metadata(handle_t *handle,
* blocks */
page_cache_get(e4b->bd_buddy_page);
page_cache_get(e4b->bd_bitmap_page);
+ /* just for sure */
+ db->bb_free_cache = 0;
}
while (*n) {
parent = *n;
@@ -4376,7 +4384,7 @@ ext4_mb_free_metadata(handle_t *handle,
if (block < entry->start_blk)
n = &(*n)->rb_left;
else if (block >= (entry->start_blk + entry->count))
- n = &(*n)->rb_right;
+ n = &(*n)->rb_right, left = 0;
else {
ext4_grp_locked_error(sb, e4b->bd_group, __func__,
"Double free of blocks %d (%d %d)",
@@ -4387,6 +4395,8 @@ ext4_mb_free_metadata(handle_t *handle,
rb_link_node(new_node, parent, n);
rb_insert_color(new_node, &db->bb_free_root);
+ if (left)
+ db->bb_free_cache = new_node;
/* Now try to see the extent can be merged to left and right */
node = rb_prev(new_node);
--
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