Re: [PATCH 1/2] super: fix calculation of shrinkable objects for small numbers
From: Dave Chinner <hidden>
Date: 2012-12-20 07:06:57
Also in:
linux-fsdevel, linux-mm
On Wed, Dec 19, 2012 at 12:40:17PM +0400, Glauber Costa wrote:
quoted hunk
The sysctl knob sysctl_vfs_cache_pressure is used to determine which percentage of the shrinkable objects in our cache we should actively try to shrink. It works great in situations in which we have many objects (at least more than 100), because the aproximation errors will be negligible. But if this is not the case, specially when total_objects < 100, we may end up concluding that we have no objects at all (total / 100 = 0, if total < 100). This is certainly not the biggest killer in the world, but may matter in very low kernel memory situations. Signed-off-by: Glauber Costa <redacted> CC: Dave Chinner <redacted> CC: "Theodore Ts'o" <redacted> CC: Al Viro <viro-RmSDqhL/yNMiFSDQTTA3OLVCufUGDwFn@public.gmane.org> --- fs/super.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)diff --git a/fs/super.c b/fs/super.c index 12f1237..660552c 100644 --- a/fs/super.c +++ b/fs/super.c@@ -104,7 +104,7 @@ static int prune_super(struct shrinker *shrink, struct shrink_control *sc) sb->s_nr_inodes_unused + fs_objects; } - total_objects = (total_objects / 100) * sysctl_vfs_cache_pressure; + total_objects = mult_frac(total_objects, sysctl_vfs_cache_pressure, 100); drop_super(sb); return total_objects;
Hi Glauber, sysctl_vfs_cache_pressure all over the place with exactly the same calculation. Can you fix all of them in one pass? Cheers, Dave. -- Dave Chinner david-FqsqvQoI3Ljby3iVrkZq2A@public.gmane.org