Messages in this thread | | | Date | Mon, 28 Dec 2009 09:27:38 +0530 | From | Balbir Singh <> | Subject | Re: [PATCH -mmotm-2009-12-10-17-19] Prevent churning of zero page in LRU list. |
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* Balbir Singh <balbir@linux.vnet.ibm.com> [2009-12-28 09:26:39]:
> * Rik van Riel <riel@redhat.com> [2009-12-27 22:22:20]: > > > On 12/27/2009 09:53 PM, Minchan Kim wrote: > > > > > >VM doesn't add zero page to LRU list. > > >It means zero page's churning in LRU list is pointless. > > > > > >As a matter of fact, zero page can't be promoted by mark_page_accessed > > >since it doesn't have PG_lru. > > > > > >This patch prevent unecessary mark_page_accessed call of zero page > > >alghouth caller want FOLL_TOUCH. > > > > > >Signed-off-by: Minchan Kim<minchan.kim@gmail.com> > > > > The code looks correct, but I wonder how frequently we run into > > the zero page in this code, vs. how much the added cost is of > > having this extra code in follow_page. > > > > What kind of problem were you running into that motivated you > > to write this patch? > > > > Frequent moving of zero page should ideally put it to the head of the > LRU list, leaving it untouched is likely to cause it to be scanned > often - no? Should this be moved to the unevictable list? >
Sorry, I replied to wrong email, I should have been clearer that this question is for Minchan Kim.
-- Balbir
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