Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751314AbaBWHxg (ORCPT ); Sun, 23 Feb 2014 02:53:36 -0500 Received: from mail-la0-f43.google.com ([209.85.215.43]:64805 "EHLO mail-la0-f43.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751006AbaBWHxe convert rfc822-to-8bit (ORCPT ); Sun, 23 Feb 2014 02:53:34 -0500 MIME-Version: 1.0 In-Reply-To: <20140221200725.GA19733@phenom.dumpdata.com> References: <20140219071605.GA25092@falcon.amazon.com> <20140219174153.GH11365@phenom.dumpdata.com> <20140221200725.GA19733@phenom.dumpdata.com> Date: Sat, 22 Feb 2014 23:53:31 -0800 Message-ID: Subject: Re: [BISECTED] Xen HVM guest hangs since 3.12-rc5 From: Steven Noonan To: Konrad Rzeszutek Wilk Cc: Linux Kernel Mailing List , Mel Gorman , Rik van Riel , Peter Zijlstra , Ingo Molnar , Andrea Arcangeli , Johannes Weiner , Srikar Dronamraju Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Feb 21, 2014 at 12:07 PM, Konrad Rzeszutek Wilk wrote: > On Thu, Feb 20, 2014 at 12:44:15PM -0800, Steven Noonan wrote: >> On Wed, Feb 19, 2014 at 1:01 PM, Steven Noonan wrote: >> > On Wed, Feb 19, 2014 at 9:41 AM, Konrad Rzeszutek Wilk >> > wrote: >> >> On Tue, Feb 18, 2014 at 11:16:05PM -0800, Steven Noonan wrote: >> >>> I've been running into problems on an Xen HVM domU. I've got a guest with NUMA >> >>> enabled, 60GB of RAM, and 3 disks attached (including root volume). 2 of the >> >>> disks are in an MD RAID0 in the guest, with an ext4 filesystem on top of that. >> >>> I was running the fio 'iometer-file-access-server.fio' example config against >> >>> that fs. During this workload, it would eventually cause a soft lockup, like >> >>> the below: >> >> >> >> I presume since you mention NUMA and Mel is CC-ed that if you boot without >> >> NUMA enabled (either via the toolstack or via Linux command line) - the issue >> >> is not present? >> > >> > I mentioned NUMA because the bisected commit is sched/numa, and the >> > guest is NUMA-enabled. I hadn't attempted booting with NUMA off. I >> > just tried with numa=off, and the workload has run in a loop for 20 >> > minutes so far with no issues (normally the issue would repro in less >> > than 5). >> >> The subject line is actually incorrect -- I did a 'git describe' on >> the result of the bisection when writing the subject line, but the >> '3.12-rc5' tag was just the base on which the code was originally >> developed. As far as what tags actually contain the commit: >> >> $ git tag --contains b795854b1fa70f6aee923ae5df74ff7afeaddcaa >> v3.13 >> v3.13-rc1 >> v3.13-rc2 >> v3.13-rc3 >> v3.13-rc4 >> v3.13-rc5 >> v3.13-rc6 >> v3.13-rc7 >> v3.13-rc8 >> v3.13.1 >> v3.13.2 >> v3.13.3 >> v3.14-rc1 >> v3.14-rc2 >> >> So it's more accurate to say it was introduced in the v3.13 merge window. >> >> In any case, does anyone have any ideas? > > There is nothing in that git commit that gives that 'AHA' feeling. > > If you revert that patch on top of the latest Linux kernel does the problem > go away? This is more of a double-check to see if the commit > is really the fault or if it exposed some latent issue. I just tried out 3.13.5 and the problem went away. Looking through the commit logs, it appears this commit (added as part of 3.13.4) resolved the issue: commit 27b4328e523b3de854229e6b505f94aa9708dde6 Author: KOSAKI Motohiro Date: Thu Feb 6 12:04:24 2014 -0800 mm: __set_page_dirty_nobuffers() uses spin_lock_irqsave() instead of spin_lock_irq() commit a85d9df1ea1d23682a0ed1e100e6965006595d06 upstream. During aio stress test, we observed the following lockdep warning. This mean AIO+numa_balancing is currently deadlockable. The problem is, aio_migratepage disable interrupt, but __set_page_dirty_nobuffers unintentionally enable it again. Generally, all helper function should use spin_lock_irqsave() instead of spin_lock_irq() because they don't know caller at all. other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&(&ctx->completion_lock)->rlock); lock(&(&ctx->completion_lock)->rlock); *** DEADLOCK *** dump_stack+0x19/0x1b print_usage_bug+0x1f7/0x208 mark_lock+0x21d/0x2a0 mark_held_locks+0xb9/0x140 trace_hardirqs_on_caller+0x105/0x1d0 trace_hardirqs_on+0xd/0x10 _raw_spin_unlock_irq+0x2c/0x50 __set_page_dirty_nobuffers+0x8c/0xf0 migrate_page_copy+0x434/0x540 aio_migratepage+0xb1/0x140 move_to_new_page+0x7d/0x230 migrate_pages+0x5e5/0x700 migrate_misplaced_page+0xbc/0xf0 do_numa_page+0x102/0x190 handle_pte_fault+0x241/0x970 handle_mm_fault+0x265/0x370 __do_page_fault+0x172/0x5a0 do_page_fault+0x1a/0x70 page_fault+0x28/0x30 Signed-off-by: KOSAKI Motohiro Cc: Larry Woodman Cc: Rik van Riel Cc: Johannes Weiner Acked-by: David Rientjes Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman >> >> >>> >> >>> [ 2536.250054] BUG: soft lockup - CPU#0 stuck for 23s! [kworker/u257:0:7] >> >>> [ 2536.250054] Modules linked in: isofs crct10dif_pclmul crct10dif_common crc32_pclmul crc32c_intel ghash_clmulni_intel aesni_intel aes_x86_64 lrw gf128mul glue_helper ablk_helper cryptd raid0 md_mod acpi_cpufreq psmouse i2c_piix4 intel_agp intel_gtt i2c_core processor serio_raw evdev microcode ext4 crc16 mbcache jbd2 ata_generic pata_acpi ata_piix libata scsi_mod floppy ixgbevf xen_privcmd xen_netfront xen_kbdfront syscopyarea sysfillrect sysimgblt fb_sys_fops xen_blkfront virtio_pci virtio_net virtio_blk virtio_ring virtio ipmi_poweroff ipmi_msghandler button >> >>> [ 2536.250054] CPU: 0 PID: 7 Comm: kworker/u257:0 Tainted: G W 3.12.0-rc4-bisect-00073-g6fe6b2d #26 >> >>> [ 2536.250054] Hardware name: Xen HVM domU, BIOS 4.2.amazon 01/14/2014 >> >>> [ 2536.250054] Workqueue: writeback bdi_writeback_workfn (flush-202:0) >> >>> [ 2536.250054] task: ffff880766533400 ti: ffff88076652e000 task.ti: ffff88076652e000 >> >>> [ 2536.250054] RIP: 0010:[] [] smp_call_function_many+0x258/0x2b0 >> >>> [ 2536.250054] RSP: 0018:ffff88076652f878 EFLAGS: 00000202 >> >>> [ 2536.250054] RAX: 000000000000000f RBX: ffff88076652f808 RCX: ffff880ef0ef74a8 >> >>> [ 2536.250054] RDX: 000000000000000f RSI: 0000000000000080 RDI: 0000000000000000 >> >>> [ 2536.250054] RBP: ffff88076652f8c0 R08: ffff880771046c00 R09: ffff880770c008e0 >> >>> [ 2536.250054] R10: 000000000000003e R11: 0000000000000210 R12: ffff88076652f7f0 >> >>> [ 2536.250054] R13: ffffffff810b859e R14: ffff88076652f7e0 R15: ffffffff810b50e7 >> >>> [ 2536.250054] FS: 0000000000000000(0000) GS:ffff880771600000(0000) knlGS:0000000000000000 >> >>> [ 2536.250054] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 >> >>> [ 2536.250054] CR2: 00007f8752bea000 CR3: 0000000001a0d000 CR4: 00000000001406f0 >> >>> [ 2536.250054] Stack: >> >>> [ 2536.250054] 0000000181275231 0000000000014d00 ffff88076652f8d0 ffffffff810564e0 >> >>> [ 2536.250054] ffff88076530b180 00007f0c8826a000 ffff880ed4d57700 ffff88076530b180 >> >>> [ 2536.250054] ffff880ed4cc6350 ffff88076652f8e8 ffffffff81056637 ffff88076530b180 >> >>> [ 2536.250054] Call Trace: >> >>> [ 2536.250054] [] ? leave_mm+0x70/0x70 >> >>> [ 2536.250054] [] native_flush_tlb_others+0x37/0x40 >> >>> [ 2536.250054] [] flush_tlb_page+0x88/0x90 >> >>> [ 2536.250054] [] ptep_clear_flush+0x34/0x40 >> >>> [ 2536.250054] [] page_mkclean+0x12e/0x1d0 >> >>> [ 2536.250054] [] clear_page_dirty_for_io+0x3b/0xe0 >> >>> [ 2536.250054] [] mpage_submit_page+0x52/0x80 [ext4] >> >>> [ 2536.250054] [] mpage_process_page_bufs+0x109/0x140 [ext4] >> >>> [ 2536.250054] [] mpage_prepare_extent_to_map+0x217/0x2d0 [ext4] >> >>> [ 2536.250054] [] ext4_writepages+0x469/0xca0 [ext4] >> >>> [ 2536.250054] [] do_writepages+0x1e/0x50 >> >>> [ 2536.250054] [] __writeback_single_inode+0x76/0x240 >> >>> [ 2536.250054] [] writeback_sb_inodes+0x282/0x420 >> >>> [ 2536.250054] [] __writeback_inodes_wb+0x7f/0xd0 >> >>> [ 2536.250054] [] wb_writeback+0x15b/0x2a0 >> >>> [ 2536.250054] [] bdi_writeback_workfn+0x1d7/0x450 >> >>> [ 2536.250054] [] process_one_work+0x25d/0x460 >> >>> [ 2536.250054] [] worker_thread+0x266/0x480 >> >>> [ 2536.250054] [] ? manage_workers.isra.18+0x3f0/0x3f0 >> >>> [ 2536.250054] [] kthread+0xbb/0xd0 >> >>> [ 2536.250054] [] ? kthread_stop+0xf0/0xf0 >> >>> [ 2536.250054] [] ret_from_fork+0x7c/0xb0 >> >>> [ 2536.250054] [] ? kthread_stop+0xf0/0xf0 >> >>> [ 2536.250054] Code: 00 74 70 48 63 35 d1 1f a1 00 ba ff ff ff ff eb 29 66 90 48 98 48 8b 0b 48 03 0c c5 00 27 ad 81 f6 41 20 01 74 14 0f 1f 44 00 00 90 f6 41 20 01 75 f8 48 63 35 a1 1f a1 00 48 8b 7b 08 83 c2 >> >>> [ 2544.900055] BUG: soft lockup - CPU#31 stuck for 24s! [systemd-journal:304] >> >>> [ 2544.900055] Modules linked in: isofs crct10dif_pclmul crct10dif_common crc32_pclmul crc32c_intel ghash_clmulni_intel aesni_intel aes_x86_64 lrw gf128mul glue_helper ablk_helper cryptd raid0 md_mod acpi_cpufreq psmouse i2c_piix4 intel_agp intel_gtt i2c_core processor serio_raw evdev microcode ext4 crc16 mbcache jbd2 ata_generic pata_acpi ata_piix libata scsi_mod floppy ixgbevf xen_privcmd xen_netfront xen_kbdfront syscopyarea sysfillrect sysimgblt fb_sys_fops xen_blkfront virtio_pci virtio_net virtio_blk virtio_ring virtio ipmi_poweroff ipmi_msghandler button >> >>> [ 2544.900055] CPU: 31 PID: 304 Comm: systemd-journal Tainted: G W 3.12.0-rc4-bisect-00073-g6fe6b2d #26 >> >>> [ 2544.900055] Hardware name: Xen HVM domU, BIOS 4.2.amazon 01/14/2014 >> >>> [ 2544.900055] task: ffff880764bcb400 ti: ffff8807653f6000 task.ti: ffff8807653f6000 >> >>> [ 2544.900055] RIP: 0010:[] [] generic_exec_single+0x80/0xa0 >> >>> [ 2544.900055] RSP: 0018:ffff8807653f7c80 EFLAGS: 00000202 >> >>> [ 2544.900055] RAX: 0000000000000080 RBX: ffffffff813207fd RCX: 0000000000000080 >> >>> [ 2544.900055] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 0000000000000080 >> >>> [ 2544.900055] RBP: ffff8807653f7cb0 R08: ffffffff8160d148 R09: ffff880770c006a8 >> >>> [ 2544.900055] R10: 0000000000000020 R11: ffffea003b490700 R12: ffffffff810b859e >> >>> [ 2544.900055] R13: ffff8807653f7bf8 R14: ffffffff810b50e7 R15: ffff8807653f7be8 >> >>> [ 2544.900055] FS: 00007f0c934cd780(0000) GS:ffff880ef0fe0000(0000) knlGS:0000000000000000 >> >>> [ 2544.900055] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 >> >>> [ 2544.900055] CR2: 00007f0c934db000 CR3: 0000000764b0f000 CR4: 00000000001406e0 >> >>> [ 2544.900055] Stack: >> >>> [ 2544.900055] 0000000106038000 000000000000000f 000000000000001f ffffffff81adcfe0 >> >>> [ 2544.900055] ffffffff810564e0 000000000000001f ffff8807653f7d20 ffffffff810cc195 >> >>> [ 2544.900055] 00007f0c934db000 ffff8807653f7cd8 ffff880ef0ef74a8 ffff880ef0ef4d00 >> >>> [ 2544.900055] Call Trace: >> >>> [ 2544.900055] [] ? leave_mm+0x70/0x70 >> >>> [ 2544.900055] [] smp_call_function_single+0x135/0x170 >> >>> [ 2544.900055] [] ? leave_mm+0x70/0x70 >> >>> [ 2544.900055] [] smp_call_function_many+0x105/0x2b0 >> >>> [ 2544.900055] [] ? leave_mm+0x70/0x70 >> >>> [ 2544.900055] [] native_flush_tlb_others+0x37/0x40 >> >>> [ 2544.900055] [] flush_tlb_mm_range+0x1fe/0x250 >> >>> [ 2544.900055] [] tlb_flush_mmu+0x37/0xa0 >> >>> [ 2544.900055] [] tlb_finish_mmu+0x14/0x50 >> >>> [ 2544.900055] [] unmap_region+0x105/0x120 >> >>> [ 2544.900055] [] ? mntput_no_expire+0x3e/0x140 >> >>> [ 2544.900055] [] ? vma_rb_erase+0x1c9/0x210 >> >>> [ 2544.900055] [] do_munmap+0x280/0x370 >> >>> [ 2544.900055] [] vm_munmap+0x41/0x60 >> >>> [ 2544.900055] [] SyS_munmap+0x22/0x30 >> >>> [ 2544.900055] [] system_call_fastpath+0x1a/0x1f >> >>> [ 2544.900055] Code: 48 89 4b 08 48 89 19 e8 4f 05 40 00 4d 39 fc 8b 55 d4 75 0f 44 89 f7 ff 15 5e 8d 95 00 8b 55 d4 0f 1f 00 85 d2 75 06 eb 0a 66 90 90 f6 43 20 01 75 f8 48 83 c4 08 5b 41 5c 41 5d 41 5e 41 5f >> >>> >> >>> At this point, the MD array will not accept any I/O, and any requests will just >> >>> result in additional soft lockup messages. >> >>> >> >>> I originally noticed this issue on Linux 3.13.3, and wasn't able to reproduce >> >>> it on 3.10.30. I eventually narrowed it down to a regression introduced between >> >>> 3.12 and 3.13. A bisection blames this commit: >> >>> >> >>> commit b795854b1fa70f6aee923ae5df74ff7afeaddcaa >> >>> Author: Mel Gorman >> >>> Date: Mon Oct 7 11:29:07 2013 +0100 >> >>> >> >>> sched/numa: Set preferred NUMA node based on number of private faults >> >>> >> >>> Ideally it would be possible to distinguish between NUMA hinting faults that >> >>> are private to a task and those that are shared. If treated identically >> >>> there is a risk that shared pages bounce between nodes depending on >> >>> the order they are referenced by tasks. Ultimately what is desirable is >> >>> that task private pages remain local to the task while shared pages are >> >>> interleaved between sharing tasks running on different nodes to give good >> >>> average performance. This is further complicated by THP as even >> >>> applications that partition their data may not be partitioning on a huge >> >>> page boundary. >> >>> >> >>> To start with, this patch assumes that multi-threaded or multi-process >> >>> applications partition their data and that in general the private accesses >> >>> are more important for cpu->memory locality in the general case. Also, >> >>> no new infrastructure is required to treat private pages properly but >> >>> interleaving for shared pages requires additional infrastructure. >> >>> >> >>> To detect private accesses the pid of the last accessing task is required >> >>> but the storage requirements are a high. This patch borrows heavily from >> >>> Ingo Molnar's patch "numa, mm, sched: Implement last-CPU+PID hash tracking" >> >>> to encode some bits from the last accessing task in the page flags as >> >>> well as the node information. Collisions will occur but it is better than >> >>> just depending on the node information. Node information is then used to >> >>> determine if a page needs to migrate. The PID information is used to detect >> >>> private/shared accesses. The preferred NUMA node is selected based on where >> >>> the maximum number of approximately private faults were measured. Shared >> >>> faults are not taken into consideration for a few reasons. >> >>> >> >>> First, if there are many tasks sharing the page then they'll all move >> >>> towards the same node. The node will be compute overloaded and then >> >>> scheduled away later only to bounce back again. Alternatively the shared >> >>> tasks would just bounce around nodes because the fault information is >> >>> effectively noise. Either way accounting for shared faults the same as >> >>> private faults can result in lower performance overall. >> >>> >> >>> The second reason is based on a hypothetical workload that has a small >> >>> number of very important, heavily accessed private pages but a large shared >> >>> array. The shared array would dominate the number of faults and be selected >> >>> as a preferred node even though it's the wrong decision. >> >>> >> >>> The third reason is that multiple threads in a process will race each >> >>> other to fault the shared page making the fault information unreliable. >> >>> >> >>> Signed-off-by: Mel Gorman >> >>> [ Fix complication error when !NUMA_BALANCING. ] >> >>> Reviewed-by: Rik van Riel >> >>> Cc: Andrea Arcangeli >> >>> Cc: Johannes Weiner >> >>> Cc: Srikar Dronamraju >> >>> Signed-off-by: Peter Zijlstra >> >>> Link: http://lkml.kernel.org/r/1381141781-10992-30-git-send-email-mgorman@suse.de >> >>> Signed-off-by: Ingo Molnar >> >>> >> >>> Here's the bisection log: >> >>> >> >>> # bad: [d8ec26d7] Linux 3.13 >> >>> # good: [5e01dc7b] Linux 3.12 >> >>> # bad: [42a2d923] Merge git://git.kernel.org/pub/scm/linux/kernel/gi >> >>> # bad: [4b4d2b46] Merge tag 'h8300-for-linus' of git://git.kernel.or >> >>> # skip: [c224b76b] Merge tag 'nfs-for-3.13-1' of git://git.linux-nfs. >> >>> # good: [ae1dd9bc] Staging: xillybus: quoted strings split across lin >> >>> # good: [beb5bfe4] Merge tag 'fixes-nc-for-linus' of git://git.kernel >> >>> # good: [f9efbce6] Merge tag 'dt-for-linus' of git://git.kernel.org/p >> >>> # good: [ad5d6989] Merge branch 'perf-core-for-linus' of git://git.ke >> >>> # bad: [39cf275a] Merge branch 'sched-core-for-linus' of git://git.k >> >>> # good: [e6628d5b] sched/numa: Reschedule task on preferred NUMA node >> >>> # bad: [04bb2f94] sched/numa: Adjust scan rate in task_numa_placemen >> >>> # bad: [e1dda8a7] sched/numa: Fix placement of workloads spread acro >> >>> # bad: [58d081b5] sched/numa: Avoid overloading CPUs on a preferred >> >>> # good: [073b5bee] sched/numa: Remove check that skips small VMAs >> >>> # bad: [6fe6b2d6] sched/numa: Do not migrate memory immediately afte >> >>> # bad: [b795854b] sched/numa: Set preferred NUMA node based on numbe >> >>> >> >>> Anyone have any ideas why this change broke things? Is there any additional >> >>> information I can provide to help pin this down? >> >>> >> >>> - Steven -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/