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ext4: use percpu data structures for lg_prealloc_list

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lg_prealloc_list seems to cry out for a per-cpu data structure; on a large
smp system I think this should be better.  I've lightly tested this change
on a 4-cpu system.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Acked-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
This commit is contained in:
Eric Sandeen 2008-09-13 15:23:29 -04:00 committed by Theodore Ts'o
parent 8eea80d52b
commit 730c213c79
1 changed files with 5 additions and 8 deletions
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13
fs/ext4/mballoc.c
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@ -2541,17 +2541,16 @@ int ext4_mb_init(struct super_block *sb, int needs_recovery)
sbi->s_mb_history_filter = EXT4_MB_HISTORY_DEFAULT;
sbi->s_mb_group_prealloc = MB_DEFAULT_GROUP_PREALLOC;
i = sizeof(struct ext4_locality_group) * nr_cpu_ids;
sbi->s_locality_groups = kmalloc(i, GFP_KERNEL);
sbi->s_locality_groups = alloc_percpu(struct ext4_locality_group);
if (sbi->s_locality_groups == NULL) {
clear_opt(sbi->s_mount_opt, MBALLOC);
kfree(sbi->s_mb_offsets);
kfree(sbi->s_mb_maxs);
return -ENOMEM;
}
for (i = 0; i < nr_cpu_ids; i++) {
for_each_possible_cpu(i) {
struct ext4_locality_group *lg;
lg = &sbi->s_locality_groups[i];
lg = per_cpu_ptr(sbi->s_locality_groups, i);
mutex_init(&lg->lg_mutex);
for (j = 0; j < PREALLOC_TB_SIZE; j++)
INIT_LIST_HEAD(&lg->lg_prealloc_list[j]);
@ -2648,8 +2647,7 @@ int ext4_mb_release(struct super_block *sb)
atomic_read(&sbi->s_mb_discarded));
}
kfree(sbi->s_locality_groups);
free_percpu(sbi->s_locality_groups);
ext4_mb_history_release(sb);
ext4_mb_destroy_per_dev_proc(sb);
@ -4106,8 +4104,7 @@ static void ext4_mb_group_or_file(struct ext4_allocation_context *ac)
* per cpu locality group is to reduce the contention between block
* request from multiple CPUs.
*/
ac->ac_lg = &sbi->s_locality_groups[get_cpu()];
put_cpu();
ac->ac_lg = per_cpu_ptr(sbi->s_locality_groups, raw_smp_processor_id());
/* we're going to use group allocation */
ac->ac_flags |= EXT4_MB_HINT_GROUP_ALLOC;