From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752952Ab0KEBaL (ORCPT ); Thu, 4 Nov 2010 21:30:11 -0400 Received: from bld-mail13.adl6.internode.on.net ([150.101.137.98]:55225 "EHLO mail.internode.on.net" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752687Ab0KEBaI (ORCPT ); Thu, 4 Nov 2010 21:30:08 -0400 Date: Fri, 5 Nov 2010 12:30:03 +1100 From: Dave Chinner To: linux-kernel@vger.kernel.org Subject: [2.6.37-rc1, OOM] virtblk: OOM in do_virtblk_request() Message-ID: <20101105013003.GE13830@dastard> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Folks, Running an IO test with lots of concurrent metadata modifications and IO under memory pressure, I hit this OOM report: [ 367.866979] xfsbufd/vdb: page allocation failure. order:0, mode:0x20 [ 367.868030] Pid: 2145, comm: xfsbufd/vdb Not tainted 2.6.36-dgc+ #634 [ 367.868030] Call Trace: [ 367.868030] [] __alloc_pages_nodemask+0x65e/0x760 [ 367.868030] [] kmem_getpages+0x62/0x160 [ 367.868030] [] fallback_alloc+0x18f/0x270 [ 367.868030] [] ____cache_alloc_node+0x9b/0x180 [ 367.868030] [] ? cache_alloc_refill+0x21c/0x260 [ 367.868030] [] __kmalloc+0x1cb/0x240 [ 367.868030] [] ? virtqueue_add_buf_gfp+0x221/0x410 [ 367.868030] [] virtqueue_add_buf_gfp+0x221/0x410 [ 367.868030] [] ? blk_rq_map_sg+0x81/0x2d0 [ 367.868030] [] do_virtblk_request+0x1f3/0x400 [ 367.868030] [] __generic_unplug_device+0x3a/0x50 [ 367.868030] [] elv_insert+0x8e/0x1b0 [ 367.868030] [] __elv_add_request+0x4a/0x90 [ 367.868030] [] __make_request+0x120/0x500 [ 367.868030] [] ? kmem_cache_alloc+0xb4/0x1e0 [ 367.868030] [] generic_make_request+0x266/0x550 [ 367.868030] [] ? mempool_alloc_slab+0x15/0x20 [ 367.868030] [] ? xfs_buf_delwri_split+0x1a9/0x1c0 [ 367.868030] [] ? kvm_clock_read+0x19/0x20 [ 367.868030] [] submit_bio+0x65/0xe0 [ 367.868030] [] _xfs_buf_ioapply+0x18c/0x360 [ 367.868030] [] ? xfs_bdstrat_cb+0x5d/0xb0 [ 367.868030] [] xfs_buf_iorequest+0x4f/0xd0 [ 367.868030] [] xfs_bdstrat_cb+0x5d/0xb0 [ 367.868030] [] xfsbufd+0x10f/0x190 [ 367.868030] [] ? xfsbufd+0x0/0x190 [ 367.868030] [] kthread+0xa6/0xb0 [ 367.868030] [] kernel_thread_helper+0x4/0x10 [ 367.868030] [] ? restore_args+0x0/0x30 [ 367.868030] [] ? kthread+0x0/0xb0 [ 367.868030] [] ? kernel_thread_helper+0x0/0x10 [ 367.868030] Mem-Info: [ 367.868030] Node 0 DMA per-cpu: [ 367.868030] CPU 0: hi: 0, btch: 1 usd: 0 [ 367.868030] CPU 1: hi: 0, btch: 1 usd: 0 [ 367.868030] CPU 2: hi: 0, btch: 1 usd: 0 [ 367.868030] CPU 3: hi: 0, btch: 1 usd: 0 [ 367.868030] CPU 4: hi: 0, btch: 1 usd: 0 [ 367.868030] CPU 5: hi: 0, btch: 1 usd: 0 [ 367.868030] CPU 6: hi: 0, btch: 1 usd: 0 [ 367.868030] CPU 7: hi: 0, btch: 1 usd: 0 [ 367.868030] Node 0 DMA32 per-cpu: [ 367.868030] CPU 0: hi: 186, btch: 31 usd: 0 [ 367.868030] CPU 1: hi: 186, btch: 31 usd: 23 [ 367.868030] CPU 2: hi: 186, btch: 31 usd: 0 [ 367.868030] CPU 3: hi: 186, btch: 31 usd: 0 [ 367.868030] CPU 4: hi: 186, btch: 31 usd: 0 [ 367.868030] CPU 5: hi: 186, btch: 31 usd: 0 [ 367.868030] CPU 6: hi: 186, btch: 31 usd: 0 [ 367.868030] CPU 7: hi: 186, btch: 31 usd: 0 [ 367.868030] Node 0 Normal per-cpu: [ 367.868030] CPU 0: hi: 186, btch: 31 usd: 0 [ 367.868030] CPU 1: hi: 186, btch: 31 usd: 0 [ 367.868030] CPU 2: hi: 186, btch: 31 usd: 0 [ 367.868030] CPU 3: hi: 186, btch: 31 usd: 0 [ 367.868030] CPU 4: hi: 186, btch: 31 usd: 0 [ 367.868030] CPU 5: hi: 186, btch: 31 usd: 0 [ 367.868030] CPU 6: hi: 186, btch: 31 usd: 0 [ 367.868030] CPU 7: hi: 186, btch: 31 usd: 0 [ 367.868030] active_anon:19790 inactive_anon:4264 isolated_anon:0 [ 367.868030] active_file:19793 inactive_file:36538 isolated_file:32 [ 367.868030] unevictable:0 dirty:0 writeback:0 unstable:0 [ 367.868030] free:0 slab_reclaimable:795356 slab_unreclaimable:118472 [ 367.868030] mapped:180 shmem:22 pagetables:523 bounce:0 [ 367.868030] Node 0 DMA free:0kB min:28kB low:32kB high:40kB active_anon:0kB inactive_anon:0kB active_file:0kB inactive_file:14804kB unevictable:0kB isolated(anon):0kB isolated(file):0kB present:15684kB mlocked:0kB dirty:0kB writeback:0kB mapped:0kB shmem:0kB slab_reclaimable:4kB slab_unreclaimable:1024kB kernel_stack:0kB pagetables:0kB unstable:0kB bounce:0kB writeback_tmp:0kB pages_scanned:1828 all_unreclaimable? no [ 367.868030] lowmem_reserve[]: 0 3512 4017 4017 [ 367.868030] Node 0 DMA32 free:0kB min:7076kB low:8844kB high:10612kB active_anon:77920kB inactive_anon:15648kB active_file:65824kB inactive_file:109788kB unevictable:0kB isolated(anon):0kB isolated(file):128kB present:3596500kB mlocked:0kB dirty:0kB writeback:0kB mapped:236kB shmem:0kB slab_reclaimable:2866144kB slab_unreclaimable:409596kB kernel_stack:80kB pagetables:372kB unstable:0kB bounce:0kB writeback_tmp:0kB pages_scanned:26652 all_unreclaimable? no [ 367.868030] lowmem_reserve[]: 0 0 505 505 [ 367.868030] Node 0 Normal free:0kB min:1016kB low:1268kB high:1524kB active_anon:1240kB inactive_anon:1408kB active_file:13348kB inactive_file:21560kB unevictable:0kB isolated(anon):0kB isolated(file):0kB present:517120kB mlocked:0kB dirty:0kB writeback:0kB mapped:484kB shmem:88kB slab_reclaimable:315276kB slab_unreclaimable:63268kB kernel_stack:1176kB pagetables:1720kB unstable:0kB bounce:0kB writeback_tmp:0kB pages_scanned:5375 all_unreclaimable? no [ 367.868030] lowmem_reserve[]: 0 0 0 0 [ 367.868030] Node 0 DMA: 0*4kB 0*8kB 0*16kB 0*32kB 0*64kB 0*128kB 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB = 0kB [ 367.868030] Node 0 DMA32: 0*4kB 0*8kB 0*16kB 0*32kB 0*64kB 0*128kB 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB = 0kB [ 367.868030] Node 0 Normal: 0*4kB 0*8kB 0*16kB 0*32kB 0*64kB 0*128kB 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB = 0kB [ 367.868030] 56938 total pagecache pages [ 367.868030] 388 pages in swap cache [ 367.868030] Swap cache stats: add 16495, delete 16107, find 524/722 [ 367.868030] Free swap = 443928kB [ 367.868030] Total swap = 497976kB [ 367.868030] 1048560 pages RAM [ 367.868030] 41977 pages reserved [ 367.868030] 51560 pages shared [ 367.868030] 949431 pages non-shared Basically, the system is _completely_ out of free pages, and failing allocations in the XFS metadata writeback path that could free up memory. I note that the code path in question in the virtio driver is doing GFP_ATOMIC allocations for the indirect ring structures. However, these allocations are not backed by a mempool and hence the system OOMs rather than makes slow progress. Shouldn't this path be using a mempool? Cheers, Dave. -- Dave Chinner david@fromorbit.com