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| author | Dipankar Sarma <dipankar@in.ibm.com> | 2006-03-08 08:55:35 +0300 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-03-09 01:14:01 +0300 |
| commit | 529bf6be5c04f2e869d07bfdb122e9fd98ade714 (patch) | |
| tree | 38514bb3941c4ac2a79266e4483663b79efa2f22 /fs/dcache.c | |
| parent | 21a1ea9eb40411d4ee29448c53b9e4c0654d6ceb (diff) | |
| download | linux-529bf6be5c04f2e869d07bfdb122e9fd98ade714.tar.xz | |
[PATCH] fix file counting
I have benchmarked this on an x86_64 NUMA system and see no significant
performance difference on kernbench. Tested on both x86_64 and powerpc.
The way we do file struct accounting is not very suitable for batched
freeing. For scalability reasons, file accounting was
constructor/destructor based. This meant that nr_files was decremented
only when the object was removed from the slab cache. This is susceptible
to slab fragmentation. With RCU based file structure, consequent batched
freeing and a test program like Serge's, we just speed this up and end up
with a very fragmented slab -
llm22:~ # cat /proc/sys/fs/file-nr
587730 0 758844
At the same time, I see only a 2000+ objects in filp cache. The following
patch I fixes this problem.
This patch changes the file counting by removing the filp_count_lock.
Instead we use a separate percpu counter, nr_files, for now and all
accesses to it are through get_nr_files() api. In the sysctl handler for
nr_files, we populate files_stat.nr_files before returning to user.
Counting files as an when they are created and destroyed (as opposed to
inside slab) allows us to correctly count open files with RCU.
Signed-off-by: Dipankar Sarma <dipankar@in.ibm.com>
Cc: "Paul E. McKenney" <paulmck@us.ibm.com>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'fs/dcache.c')
| -rw-r--r-- | fs/dcache.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/dcache.c b/fs/dcache.c index a173bba32666..11dc83092d4a 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -1736,7 +1736,7 @@ void __init vfs_caches_init(unsigned long mempages) SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL); filp_cachep = kmem_cache_create("filp", sizeof(struct file), 0, - SLAB_HWCACHE_ALIGN|SLAB_PANIC, filp_ctor, filp_dtor); + SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL); dcache_init(mempages); inode_init(mempages); |