On 8/8/2023 10:43 AM, Yu Zhao wrote: > On Mon, Aug 7, 2023 at 8:10 PM Yin Fengwei <fengwei.yin@xxxxxxxxx> wrote: >> >> In madvise_cold_or_pageout_pte_range() and madvise_free_pte_range(), >> folio_mapcount() is used to check whether the folio is shared. But it's >> not correct as folio_mapcount() returns total mapcount of large folio. >> >> Use folio_estimated_sharers() here as the estimated number is enough. >> >> >> This patchset will fix the cases: >> User space application call madvise() with MADV_FREE, MADV_COLD and >> MADV_PAGEOUT for specific address range. There are THP mapped to the >> range. Without the patchset, the THP is skipped. With the patch, the >> THP will be split and handled accordingly. >> >> David reported the cow self test skip some cases because of >> MADV_PAGEOUT skip THP: >> https://lore.kernel.org/linux-mm/9e92e42d-488f-47db-ac9d-75b24cd0d037@xxxxxxxxx/T/#mbf0f2ec7fbe45da47526de1d7036183981691e81 >> and I confirmed this patchset make it work again. >> >> >> Changelog from v1: >> - Avoid two Fixes tags make backport harder. Thank Andrew for pointing >> this out. >> >> - Add note section to mention this is a temporary fix which is fine >> to reduce user-visble effects. For long term fix, we should wait for >> David's solution. Thank Ryan and David for pointing this out. >> >> - Spell user-visible effects out. Then people could decide whether >> these patches are necessary for stable branch. Thank Andrew for >> pointing this out. > > LGTM, thank you. Thanks a lot for looking at this patchset. Regards Yin, Fengwei
