Re: [PATCH 3/3][RFC] swsusp: shrink file cache first

From: KOSAKI Motohiro
Date: Sun Mar 01 2009 - 05:39:44 EST


> > hm? And if this approach leads to less-than-optimum performance after
> > resume then the fault lies with core page reclaim - it reclaimed the
> > wrong pages!
> >
> > That actually was my thinking when I first worked on
> > shrink_all_memory() and it did turn out to be surprisingly hard to
> > simply reuse the existing reclaim code for this application. Things
> > kept on going wrong. IIRC this was because we were freeing pages as we
> > were reclaiming, so the page reclaim logic kept on seeing all these
> > free pages and kept on wanting to bale out.
> >
> > Now, the simple and obvious fix to this is not to free the pages - just
> > keep on allocating pages and storing them locally until we have
> > "enough" memory. Then when we're all done, dump them all straight onto
> > to the freelists.
> >
> > But for some reason which I do not recall, we couldn't do that.
>
> We used to do that. I remember having loop doing get_free_page and
> doing linklist of them. I believe it was considered quite an hack.
>
> .....one reason is that ee don't want to OOMkill anything if memory is
> low, we want to abort the hibernation...
>
> Sorry for being late.....

Not at all.
your information is really helpful.

maybe, I expect we can make simplification without oomkill...



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