Messages in this thread | | | Subject | Re: [Question] Mlocked count will not be decreased | From | Yisheng Xie <> | Date | Thu, 25 May 2017 09:00:33 +0800 |
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Hi Vlastimil,
Thanks for comment. On 2017/5/24 19:52, Vlastimil Babka wrote: > On 05/24/2017 01:38 PM, Xishi Qiu wrote: >>> >>> Race condition with what? Who else would isolate our pages? >>> >> >> Hi Vlastimil, >> >> I find the root cause, if the page was not cached on the current cpu, >> lru_add_drain() will not push it to LRU. So we should handle fail >> case in mlock_vma_page(). > > Yeah that would explain it. > >> follow_page_pte() >> ... >> if (page->mapping && trylock_page(page)) { >> lru_add_drain(); /* push cached pages to LRU */ >> /* >> * Because we lock page here, and migration is >> * blocked by the pte's page reference, and we >> * know the page is still mapped, we don't even >> * need to check for file-cache page truncation. >> */ >> mlock_vma_page(page); >> unlock_page(page); >> } >> ... >> >> I think we should add yisheng's patch, also we should add the following change. >> I think it is better than use lru_add_drain_all(). > > I agree about yisheng's fix (but v2 didn't address my comments). I don't > think we should add the hunk below, as that deviates from the rest of > the design. > Sorry, I have sent the patch before your comment. Anyway I will send another version as your suggestion.
Thanks Yisheng Xie
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