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From: Zhiyong Ye <yezhiyong@bytedance.com>
To: qemu-block@nongnu.org, qemu-devel@nongnu.org
Cc: kwolf@redhat.com, Zhiyong Ye <yezhiyong@bytedance.com>,
	mreitz@redhat.com
Subject: [PATCH 0/1] block: Do not poll in bdrv_set_aio_context_ignore() when acquiring new_context
Date: Mon, 12 Jul 2021 13:38:30 +0800	[thread overview]
Message-ID: <20210712053831.51722-1-yezhiyong@bytedance.com> (raw)

When bdrv_set_aio_context_ignore() is called in the main loop to change
the AioContext onto the IO thread, the bdrv_drain_invoke_entry() never
gets to run and the IO thread hangs at co_schedule_bh_cb().

This is because the AioContext is occupied by the main thread after
being attached to the IO thread, and the main thread poll in
bdrv_drained_end() waiting for the IO request to be drained, but the IO
thread cannot acquire the AioContext, which leads to deadlock.

Zhiyong Ye (1):
  block: Do not poll in bdrv_set_aio_context_ignore() when acquiring new_context

 block.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

-- 
2.11.0



             reply	other threads:[~2021-07-12  5:41 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-12  5:38 Zhiyong Ye [this message]
2021-07-12  5:38 ` [PATCH 1/1] block: Do not poll in bdrv_set_aio_context_ignore() when acquiring new_context Zhiyong Ye
2021-07-19 10:24   ` Kevin Wolf
2021-07-20 13:07     ` Zhiyong Ye

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