Re: Fw: two 2.6.13-rc3-mm3 oddities
From: Dipankar Sarma
Date: Mon Aug 08 2005 - 17:59:42 EST
On Mon, Aug 08, 2005 at 10:25:59AM -0700, Andrew Morton wrote:
> Dipankar Sarma <dipankar@xxxxxxxxxx> wrote:
> > > But: IIRC the counters were moved to the ctor/dtor for performance
> > > reasons, I'd guess mbligh ran into cache line trashing on the
> > > filp_count_lock spinlock with reaim or something like that.
> > Ah, so the whole idea was to inc/dec nr_files less often so
> > that we reduce contention on filp_count_lock, right ? This however
> > causes skews nr_files by the size of the slab array, AFAICS.
> > Since we check nr_files before we allocate files from slab, the
> > check seems inaccurate.
> > Anyway, I guess, I need to look at scaling the file counting
> > first.
> Something like vm_acct_memory() or percpu_counter would suit.
Yes, that is what I am doing, except that because of the sysctl
stuff, I now have to wallow myself in /proc code.
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