A-Team_Digital_Solutions/android_kernel_motorola_sm6375
Watch
2
0
Fork
You've already forked android_kernel_motorola_sm6375
 0
mirror of https://github.com/BobTheBlinker/android_kernel_motorola_sm6375.git synced 2026-10-28 18:51:56 -04:00
Code Issues Projects Releases Packages Wiki Activity

shrink_dcache_sb speedup

Browse source 
This patch makes shrink_dcache_sb consistent with dentry pruning policy.

On the first pass we iterate over dentry unused list and prepare some
dentries for removal.

However, since the existing code moves evicted dentries to the beginning of
the LRU it can happen that fresh dentries from other superblocks will be
inserted *before* our dentries.

This can result in significant slowdown of shrink_dcache_sb().  Moreover,
for virtual filesystems like unionfs which can call dput() during dentries
kill existing code results in O(n^2) complexity.

We observed 2 minutes shrink_dcache_sb() with only 35000 dentries.

To avoid this effects we propose to isolate sb dentries at the end
of LRU list.

Signed-off-by: Denis V. Lunev <[email protected]>
Signed-off-by: Kirill Korotaev <[email protected]>
Signed-off-by: Andrey Mirkin <[email protected]>
Cc: Neil Brown <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
This commit is contained in:
Denis V. Lunev 2007-10-16 23:29:53 -07:00 • committed by Linus Torvalds
commit 37c42524d6
2 changed files with 15 additions and 3 deletions
Download patch file Download diff file Expand all files Collapse all files

6
fs/dcache.c
View file

@ -553,18 +553,18 @@ void shrink_dcache_sb(struct super_block * sb)
* superblock to the most recent end of the unused list.
*/
spin_lock(&dcache_lock);
list_for_each_safe(tmp, next, &dentry_unused) {
list_for_each_prev_safe(tmp, next, &dentry_unused) {
dentry = list_entry(tmp, struct dentry, d_lru);
if (dentry->d_sb != sb)
continue;
list_move(tmp, &dentry_unused);
list_move_tail(tmp, &dentry_unused);
}
/*
* Pass two ... free the dentries for this superblock.
*/
repeat:
list_for_each_safe(tmp, next, &dentry_unused) {
list_for_each_prev_safe(tmp, next, &dentry_unused) {
dentry = list_entry(tmp, struct dentry, d_lru);
if (dentry->d_sb != sb)
continue;