On Wed, 22 Aug 2012, Andi Kleen wrote: > Andrea Arcangeli <aarcange@xxxxxxxxxx> 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 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>