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| author | Dipankar Sarma <dipankar@in.ibm.com> | 2006-03-08 06:55:35 +0100 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-03-08 23:14:01 +0100 |
| commit | 529bf6be5c04f2e869d07bfdb122e9fd98ade714 (patch) | |
| tree | 38514bb3941c4ac2a79266e4483663b79efa2f22 /include | |
| parent | [PATCH] rcu batch tuning (diff) | |
| download | linux-529bf6be5c04f2e869d07bfdb122e9fd98ade714.tar.xz linux-529bf6be5c04f2e869d07bfdb122e9fd98ade714.zip | |
[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 'include')
| -rw-r--r-- | include/linux/file.h | 2 | ||||
| -rw-r--r-- | include/linux/fs.h | 1 |
2 files changed, 1 insertions, 2 deletions
diff --git a/include/linux/file.h b/include/linux/file.h index 418b6101b59a..9901b850f2e4 100644 --- a/include/linux/file.h +++ b/include/linux/file.h @@ -60,8 +60,6 @@ extern void put_filp(struct file *); extern int get_unused_fd(void); extern void FASTCALL(put_unused_fd(unsigned int fd)); struct kmem_cache; -extern void filp_ctor(void * objp, struct kmem_cache *cachep, unsigned long cflags); -extern void filp_dtor(void * objp, struct kmem_cache *cachep, unsigned long dflags); extern struct file ** alloc_fd_array(int); extern void free_fd_array(struct file **, int); diff --git a/include/linux/fs.h b/include/linux/fs.h index 0cc34b1c42c9..51c0c93bdf93 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -35,6 +35,7 @@ struct files_stat_struct { int max_files; /* tunable */ }; extern struct files_stat_struct files_stat; +extern int get_max_files(void); struct inodes_stat_t { int nr_inodes; |