Messages in this thread | | | Subject | Re: [PATCH -next 1/8] md/raid10: prevent soft lockup while flush writes | From | Yu Kuai <> | Date | Tue, 25 Apr 2023 14:47:22 +0800 |
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Hi,
在 2023/04/25 14:39, Song Liu 写道: > On Mon, Apr 24, 2023 at 11:16 PM Yu Kuai <yukuai1@huaweicloud.com> wrote: >> >> Hi, >> >> 在 2023/04/25 8:23, Song Liu 写道: >>> On Thu, Apr 20, 2023 at 4:31 AM Yu Kuai <yukuai1@huaweicloud.com> wrote: >>>> >>>> From: Yu Kuai <yukuai3@huawei.com> >>>> >>>> Currently, there is no limit for raid1/raid10 plugged bio. While flushing >>>> writes, raid1 has cond_resched() while raid10 doesn't, and too many >>>> writes can cause soft lockup. >>>> >>>> Follow up soft lockup can be triggered easily with writeback test for >>>> raid10 with ramdisks: >>>> >>>> watchdog: BUG: soft lockup - CPU#10 stuck for 27s! [md0_raid10:1293] >>>> Call Trace: >>>> <TASK> >>>> call_rcu+0x16/0x20 >>>> put_object+0x41/0x80 >>>> __delete_object+0x50/0x90 >>>> delete_object_full+0x2b/0x40 >>>> kmemleak_free+0x46/0xa0 >>>> slab_free_freelist_hook.constprop.0+0xed/0x1a0 >>>> kmem_cache_free+0xfd/0x300 >>>> mempool_free_slab+0x1f/0x30 >>>> mempool_free+0x3a/0x100 >>>> bio_free+0x59/0x80 >>>> bio_put+0xcf/0x2c0 >>>> free_r10bio+0xbf/0xf0 >>>> raid_end_bio_io+0x78/0xb0 >>>> one_write_done+0x8a/0xa0 >>>> raid10_end_write_request+0x1b4/0x430 >>>> bio_endio+0x175/0x320 >>>> brd_submit_bio+0x3b9/0x9b7 [brd] >>>> __submit_bio+0x69/0xe0 >>>> submit_bio_noacct_nocheck+0x1e6/0x5a0 >>>> submit_bio_noacct+0x38c/0x7e0 >>>> flush_pending_writes+0xf0/0x240 >>>> raid10d+0xac/0x1ed0 >>> >>> Is it possible to trigger this with a mdadm test? >>> >> >> The test I mentioned in patch 8 can trigger this problem reliablity, so >> I this add a new test can achieve this. > > To be clear, by "mdadm test" I mean the tests included in mdadm: > > https://git.kernel.org/pub/scm/utils/mdadm/mdadm.git/tree/tests > > Could you please try to add a test? If it works, we should add it to > mdadm.
Yes, of course. However, I'm not familiar how mdadm tests works yet, it might take some time. By the way, I'll be good if I can add the test to blktests if possible.
Thanks, Kuai > > Thanks, > Song > . >
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