From: Jing Zhang <zj.barak@xxxxxxxxx>
Date: Tue Mar 30 20:35:22 2010
With the added cache, better group locality may be earned when
allocating blocks.
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/mballoc.c 2009-12-03 11:51:22.000000000 +0800
+++ ext4_mm_leak/mballoc-13.c 2010-03-30 20:28:08.000000000 +0800
@@ -4183,12 +4183,20 @@ static int ext4_mb_discard_preallocation
ext4_group_t i, ngroups = ext4_get_groups_count(sb);
int ret;
int freed = 0;
+ static ext4_group_t grp_cache = 0;
trace_ext4_mb_discard_preallocations(sb, needed);
- for (i = 0; i < ngroups && needed > 0; i++) {
- ret = ext4_mb_discard_group_preallocations(sb, i, needed);
+ if (needed <= 0)
+ return freed;
+ for (i = 0; i < ngroups; i++) {
+ if (grp_cache >= ngroups)
+ grp_cache -= ngroups;
+ ret = ext4_mb_discard_group_preallocations(sb, grp_cache, needed);
freed += ret;
needed -= ret;
+ if (needed <= 0)
+ break;
+ grp_cache++;
}
return freed;
--
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