Messages in this thread | | | Date | Wed, 18 Jan 2023 22:33:39 +0100 | From | Michal Hocko <> | Subject | Re: [PATCH 17/41] mm/mmap: move VMA locking before anon_vma_lock_write call |
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On Wed 18-01-23 10:09:29, Suren Baghdasaryan wrote: > On Wed, Jan 18, 2023 at 1:23 AM Michal Hocko <mhocko@suse.com> wrote: > > > > On Tue 17-01-23 18:01:01, Suren Baghdasaryan wrote: > > > On Tue, Jan 17, 2023 at 7:16 AM Michal Hocko <mhocko@suse.com> wrote: > > > > > > > > On Mon 09-01-23 12:53:12, Suren Baghdasaryan wrote: > > > > > Move VMA flag modification (which now implies VMA locking) before > > > > > anon_vma_lock_write to match the locking order of page fault handler. > > > > > > > > Does this changelog assumes per vma locking in the #PF? > > > > > > Hmm, you are right. Page fault handlers do not use per-vma locks yet > > > but the changelog already talks about that. Maybe I should change it > > > to simply: > > > ``` > > > Move VMA flag modification (which now implies VMA locking) before > > > vma_adjust_trans_huge() to ensure the modifications are done after VMA > > > has been locked. > > > > Because .... > > because vma_adjust_trans_huge() modifies the VMA and such > modifications should be done under VMA write-lock protection.
So it will become: Move VMA flag modification (which now implies VMA locking) before vma_adjust_trans_huge() to ensure the modifications are done after VMA has been locked. Because vma_adjust_trans_huge() modifies the VMA and such modifications should be done under VMA write-lock protection.
which is effectivelly saying vma_adjust_trans_huge() modifies the VMA and such modifications should be done under VMA write-lock protection so move VMA flag modifications before so all of them are covered by the same write protection.
right? -- Michal Hocko SUSE Labs
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