Re: [PATCH V2 2/2] change shrinker API by passing shrink_control struct

[Ying Han <yinghan@google.com>]

Hmm, got Nick's email wrong.

--Ying

On Tue, Apr 26, 2011 at 6:15 PM, Ying Han <yinghan@google.com> wrote:
> On Tue, Apr 26, 2011 at 5:47 PM, KOSAKI Motohiro
> <kosaki.motohiro@jp.fujitsu.com> wrote:
>>> > >  {
>>> > >       struct xfs_mount *mp;
>>> > >       struct xfs_perag *pag;
>>> > >       xfs_agnumber_t  ag;
>>> > >       int             reclaimable;
>>> > > +     int nr_to_scan = sc->nr_slab_to_reclaim;
>>> > > +     gfp_t gfp_mask = sc->gfp_mask;
>>> >
>>> > And, this very near meaning field .nr_scanned and .nr_slab_to_reclaim
>>> > poped up new question.
>>> > Why don't we pass more clever slab shrinker target? Why do we need pass
>>> > similar two argument?
>>> >
>>>
>>> I renamed the nr_slab_to_reclaim and nr_scanned in shrink struct.
>>
>> Oh no. that's not naming issue. example, Nick's previous similar patch pass
>> zone-total-pages and how-much-scanned-pages. (ie shrink_slab don't calculate
>> current magical target scanning objects anymore)
>>        ie,  "4 *  max_pass  * (scanned / nr- lru_pages-in-zones)"
>>
>> Instead, individual shrink_slab callback calculate this one.
>> see git://git.kernel.org/pub/scm/linux/kernel/git/npiggin/linux-npiggin.git
>>
>> I'm curious why you change the design from another guy's previous very similar effort and
>> We have to be convinced which is better.
>
> Thank you for the pointer. My patch is intended to consolidate all
> existing parameters passed from reclaim code
> to the shrinker.
>
> Talked w/ Nick and Andrew from last LSF,  we agree that this patch
> will be useful for other extensions later which allows us easily
> adding extensions to the shrinkers without shrinker files. Nick and I
> talked about the effort later to pass the nodemask down to the
> shrinker. He is cc-ed in the thread. Another thing I would like to
> repost is to add the reclaim priority down to the shrinker, which we
> won't throw tons of page caches pages by reclaiming one inode slab
> object.
>
> --Ying
>
>
>
>>
>>
>>
>>
>

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