Messages in this thread | | | Date | Thu, 15 Mar 2012 15:44:00 +0100 | From | Michal Hocko <> | Subject | Re: [PATCH] mm: hugetlb: defer freeing pages when gathering surplus pages |
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On Wed 14-03-12 21:08:13, Hillf Danton wrote: > On Wed, Mar 14, 2012 at 7:13 PM, Michal Hocko <mhocko@suse.cz> wrote: > > [Sorry for the late reply but I was away from email for quite sometime] > > > > Nice to see you back:)
Thanks
> > > On Tue 14-02-12 20:53:51, Hillf Danton wrote: > >> When gathering surplus pages, the number of needed pages is recomputed after > >> reacquiring hugetlb lock to catch changes in resv_huge_pages and > >> free_huge_pages. Plus it is recomputed with the number of newly allocated > >> pages involved. > >> > >> Thus freeing pages could be deferred a bit to see if the final page request is > >> satisfied, though pages could be allocated less than needed. > > > > The patch looks OK but I am missing a word why we need it. I guess > > False negative is removed as it should be.
Right, I meant false negative. Would be nice to have it in the changelog... Anyway, Andrew has already picked up the patch I guess. Just in case
Reviewed-by: Michal Hocko <mhocko@suse.cz>
> > your primary motivation is that we want to reduce false positives when > > we fail to allocate surplus pages while somebody freed some in the > > background. > > What is the workload that you observed such a behavior? Or is this just > > from the code review? > > > The second.
OK
-- Michal Hocko SUSE Labs SUSE LINUX s.r.o. Lihovarska 1060/12 190 00 Praha 9 Czech Republic
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