Re: [PATCH v4 01/11] mm: x86: move _PAGE_SWP_SOFT_DIRTY from bit 7 to bit 1

2017-03-24 Thread Zi Yan
Tim Chen wrote: > On Mon, 2017-03-13 at 11:44 -0400, Zi Yan wrote: >> From: Naoya Horiguchi >> >> pmd_present() checks _PAGE_PSE along with _PAGE_PRESENT to avoid >> false negative return when it races with thp spilt >> (during which _PAGE_PRESENT is temporary cleared.) I don't think that >> dro

Re: [PATCH v4 01/11] mm: x86: move _PAGE_SWP_SOFT_DIRTY from bit 7 to bit 1

2017-03-24 Thread Tim Chen
On Mon, 2017-03-13 at 11:44 -0400, Zi Yan wrote: > From: Naoya Horiguchi > > pmd_present() checks _PAGE_PSE along with _PAGE_PRESENT to avoid > false negative return when it races with thp spilt > (during which _PAGE_PRESENT is temporary cleared.) I don't think that > dropping _PAGE_PSE check in

[PATCH v4 01/11] mm: x86: move _PAGE_SWP_SOFT_DIRTY from bit 7 to bit 1

2017-03-13 Thread Zi Yan
From: Naoya Horiguchi pmd_present() checks _PAGE_PSE along with _PAGE_PRESENT to avoid false negative return when it races with thp spilt (during which _PAGE_PRESENT is temporary cleared.) I don't think that dropping _PAGE_PSE check in pmd_present() works well because it can hurt optimization of