On Wed, 8 Jul 2015, Dave Jones wrote: > I've got a box with 4GB of RAM that I've driven into oom (so much so that e1000 can't > alloc a single page, so I can't even ping it). But over serial console I noticed this.. > > [158831.710001] DMA32 free:1624kB min:6880kB low:8600kB high:10320kB active_anon:407004kB inactive_anon:799300kB active_file:516kB inactive_file:6644kB unevictable:0kB > isolated(anon):0kB isolated(file):0kB present:3127220kB managed:3043108kB mlocked:0kB dirty:6680kB writeback:64kB mapped:31544kB shmem:1146792kB > slab_reclaimable:46812kB slab_unreclaimable:388364kB kernel_stack:2288kB pagetables:2076kB unstable:0kB bounce:0kB free_pcp:0kB local_pcp:0kB > free_cma:0kB writeback_tmp:0kB pages_scanned:70152496980 all_unreclaimable? yes > > How come that 'pages_scanned' number is greater than the number of pages in the system ? > Does kswapd iterate over the same pages a number of times each time the page allocator fails ? > > > I've managed to hit this a couple times this week, where the oom killer kicks in, kills some > processes, but then the machine goes into a death spiral of looping in the page allocator. > Once that begins, it never tries to oom kill again, just hours of page allocation failure messages. > We don't have the full oom log to see if there's any indication of a problem, but pages_scanned should be able to grow very large since it's never reset as a result of either memory freeing or periodic pcp flush (I notice free_pcp is 0kB above) so pages_scanned never gets cleared. -- 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>