| Date | Wed, 22 Aug 2012 14:22:33 -0700 (PDT) | From | Hugh Dickins <> | Subject | Re: [PATCH 19/36] autonuma: memory follows CPU algorithm and task/mm_autonuma stats collection |
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On Wed, 22 Aug 2012, Andi Kleen wrote: > Andrea Arcangeli <aarcange@redhat.com> writes: > > + /* > > + * Take the lock with irqs disabled to avoid a lock > > + * inversion with the lru_lock. The lru_lock is taken > > + * before the autonuma_migrate_lock in > > + * split_huge_page. If we didn't disable irqs, the > > + * lru_lock could be taken by interrupts after we have > > + * obtained the autonuma_migrate_lock here. > > + */ > > Which interrupt code takes the lru_lock? That sounds like a bug.
Not a bug: the clearest example is end_page_writeback() calling rotate_reclaimable_page(); but I think once you probe deeper, you find some other mm/swap.c pagevec operations which may get called from interrupt, and end up freeing unrelated PageLRU pages.
Hugh
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