Re: VM balancing issues on 2.6.13: dentry cache not getting shrunk enough
Bharata B Rao <bharata <at> in.ibm.com>
2005-10-02 16:32:29 GMT
On Thu, Sep 15, 2005 at 10:29:10AM -0300, Marcelo Tosatti wrote:
> On Thu, Sep 15, 2005 at 03:09:45PM +0530, Bharata B Rao wrote:
> > On Wed, Sep 14, 2005 at 08:08:43PM -0300, Marcelo Tosatti wrote:
> > > On Tue, Sep 13, 2005 at 02:17:52PM +0530, Bharata B Rao wrote:
> > > >
> > <snip>
> > > > First is dentry_stats patch which collects some dcache statistics
> > > > and puts it into /proc/meminfo. This patch provides information
> > > > about how dentries are distributed in dcache slab pages, how many
> > > > free and in use dentries are present in dentry_unused lru list and
> > > > how prune_dcache() performs with respect to freeing the requested
> > > > number of dentries.
> > >
> > > Bharata,
> > >
> > > Ideally one should move the "nr_requested/nr_freed" counters from your
> > > stats patch into "struct shrinker" (or somewhere else more appropriate
> > > in which per-shrinkable-cache stats are maintained), and use the
> > > "mod_page_state" infrastructure to do lockless per-CPU accounting. ie.
> > > break /proc/vmstats's "slabs_scanned" apart in meaningful pieces.
> > Yes, I agree that we should have the nr_requested and nr_freed type of
> > counters in appropriate place. And "struct shrinker" is probably right
> > place for it.
> > Essentially you are suggesting that we maintain per cpu statistics
> > of 'requested to free'(scanned) slab objects and actual freed objects.
> > And this should be on per shrinkable cache basis.