Re: [PATCH v3 0/2] tmpfs: Improve tmpfs scalability

[Minchan Kim]

On Fri, Jun 18, 2010 at 8:56 AM, Tim Chen <tim.c.chen@xxxxxxxxxxxxxxx> wrote:
> This patch series helps to resolve scalability problem
> for tmpfs. ÂWith these patches, Aim7 fserver throughput for tmpfs
> improved by 270% on a 4 socket, 32 cores NHM-EX system.
>
> In current implementation of tmpfs, whenever we
> get a new page, stat_lock in shmem_sb_info needs to be acquired.
> This causes a lot of lock contentions when multiple
> threads are using tmpfs simultaneously, which makes
> system with large number of cpus scale poorly.
> Almost 75% of cpu time was spent contending on
> stat_lock when we ran Aim7 fserver load with 128 threads
> on a 4 socket, 32 cores NHM-EX system.
>
> We made use of the percpu_counter library for used blocks accounting to
> speed up the getting and returning of blocks to local per cpu counter
> without lock acquisition.
>
> The first patch in the series add a function to provide
> fast but accurate comparison for the percpu_counter library.
>
> The second patch update the shmem code of tmpfs to use percpu_counter
> library to improve tmpfs performance.
>

Patch series seems good to me.

If you send a patch, please, make sure Cc list.
tmpfs is related to mm. So when you send patch at next time, please Cc linux-mm.

You can use ./script/get_maintainer.pl -f mm/shmem.c

Thanks.
-- 
Kind regards,
Minchan Kim
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