iv/linux
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

tmpfs: no need to use i_lock

Browse Source 
2.6.36's 7e496299d4 ("tmpfs: make tmpfs scalable with percpu_counter for
used blocks") to make tmpfs scalable with percpu_counter used
inode->i_lock in place of sbinfo->stat_lock around i_blocks updates; but
that was adverse to scalability, and unnecessary, since info->lock is
already held there in the fast paths.

Remove those uses of i_lock, and add info->lock in the three error paths
where it's then needed across shmem_free_blocks().  It's not actually
needed across shmem_unacct_blocks(), but they're so often paired that it
looks wrong to split them apart.

Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Tim Chen <tim.c.chen@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Hugh Dickins 2011-07-25 17:12:26 -07:00 committed by Linus Torvalds
parent d0823576bf
commit d515afe88a
1 changed files with 6 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

14
mm/shmem.c
View File

@ -241,9 +241,7 @@ static void shmem_free_blocks(struct inode *inode, long pages)
struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb);
if (sbinfo->max_blocks) {
percpu_counter_add(&sbinfo->used_blocks, -pages);
spin_lock(&inode->i_lock);
inode->i_blocks -= pages*BLOCKS_PER_PAGE;
spin_unlock(&inode->i_lock);
}
}
@ -432,9 +430,7 @@ static swp_entry_t *shmem_swp_alloc(struct shmem_inode_info *info, unsigned long
sbinfo->max_blocks - 1) >= 0)
return ERR_PTR(-ENOSPC);
percpu_counter_inc(&sbinfo->used_blocks);
spin_lock(&inode->i_lock);
inode->i_blocks += BLOCKS_PER_PAGE;
spin_unlock(&inode->i_lock);
}
spin_unlock(&info->lock);
@ -1421,9 +1417,7 @@ repeat:
shmem_acct_block(info->flags))
goto nospace;
percpu_counter_inc(&sbinfo->used_blocks);
spin_lock(&inode->i_lock);
inode->i_blocks += BLOCKS_PER_PAGE;
spin_unlock(&inode->i_lock);
} else if (shmem_acct_block(info->flags))
goto nospace;
@ -1434,8 +1428,10 @@ repeat:
spin_unlock(&info->lock);
filepage = shmem_alloc_page(gfp, info, idx);
if (!filepage) {
spin_lock(&info->lock);
shmem_unacct_blocks(info->flags, 1);
shmem_free_blocks(inode, 1);
spin_unlock(&info->lock);
error = -ENOMEM;
goto failed;
}
@ -1449,8 +1445,10 @@ repeat:
current->mm, GFP_KERNEL);
if (error) {
page_cache_release(filepage);
spin_lock(&info->lock);
shmem_unacct_blocks(info->flags, 1);
shmem_free_blocks(inode, 1);
spin_unlock(&info->lock);
filepage = NULL;
goto failed;
}
@ -1480,10 +1478,10 @@ repeat:
* be done automatically.
*/
if (ret) {
spin_unlock(&info->lock);
page_cache_release(filepage);
shmem_unacct_blocks(info->flags, 1);
shmem_free_blocks(inode, 1);
spin_unlock(&info->lock);
page_cache_release(filepage);
filepage = NULL;
if (error)
goto failed;