From: Fam Zheng <famz@redhat.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: qemu-devel@nongnu.org, stefanha@redhat.com
Subject: Re: [Qemu-devel] [PATCH v2 09/16] block: wait for all pending I/O when doing synchronous requests
Date: Thu, 17 Mar 2016 10:55:32 +0800 [thread overview]
Message-ID: <20160317025532.GK23821@ad.usersys.redhat.com> (raw)
In-Reply-To: <1458137817-15383-10-git-send-email-pbonzini@redhat.com>
On Wed, 03/16 15:16, Paolo Bonzini wrote:
> Synchronous I/O should in general happen either in the main thread (e.g.
> for bdrv_open and bdrv_create) or between bdrv_drained_begin and
> bdrv_drained_end. Therefore, the simplest way to wait for it to finish
> is to wait for _all_ pending I/O to complete.
>
> In fact, there was one case in bdrv_close where we explicitly drained
> after bdrv_flush; this is now unnecessary. And we should probably have
> called bdrv_drain_all after calls to bdrv_flush_all, which is now
> unnecessary too.
>
> This decouples synchronous I/O from aio_poll. When the request used
> not to be tracked as part of bdrv_drain (e.g. bdrv_co_get_block_status)
> we need to update the in_flight count.
>
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
next prev parent reply other threads:[~2016-03-17 2:55 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-16 14:16 [Qemu-devel] [PATCH v2 00/16] AioContext fine-grained locking, part 1 of 3, including bdrv_drain rewrite Paolo Bonzini
2016-03-16 14:16 ` [Qemu-devel] [PATCH v2 01/16] block: make bdrv_start_throttled_reqs return void Paolo Bonzini
2016-03-16 14:16 ` [Qemu-devel] [PATCH v2 02/16] block: move restarting of throttled reqs to block/throttle-groups.c Paolo Bonzini
2016-03-17 2:39 ` Fam Zheng
2016-03-16 14:16 ` [Qemu-devel] [PATCH v2 03/16] block: introduce bdrv_no_throttling_begin/end Paolo Bonzini
2016-03-17 2:52 ` Fam Zheng
2016-03-16 14:16 ` [Qemu-devel] [PATCH v2 04/16] block: plug whole tree at once, introduce bdrv_io_unplugged_begin/end Paolo Bonzini
2016-03-16 14:16 ` [Qemu-devel] [PATCH v2 05/16] mirror: use bottom half to re-enter coroutine Paolo Bonzini
2016-03-17 2:23 ` Fam Zheng
2016-03-16 14:16 ` [Qemu-devel] [PATCH v2 06/16] block: add BDS field to count in-flight requests Paolo Bonzini
2016-03-17 2:53 ` Fam Zheng
2016-03-16 14:16 ` [Qemu-devel] [PATCH v2 07/16] block: change drain to look only at one child at a time Paolo Bonzini
2016-03-17 3:10 ` Fam Zheng
2016-03-16 14:16 ` [Qemu-devel] [PATCH v2 08/16] blockjob: introduce .drain callback for jobs Paolo Bonzini
2016-03-16 14:16 ` [Qemu-devel] [PATCH v2 09/16] block: wait for all pending I/O when doing synchronous requests Paolo Bonzini
2016-03-17 2:55 ` Fam Zheng [this message]
2016-03-16 14:16 ` [Qemu-devel] [PATCH v2 10/16] nfs: replace aio_poll with bdrv_drain Paolo Bonzini
2016-03-16 14:16 ` [Qemu-devel] [PATCH v2 11/16] sheepdog: disable dataplane Paolo Bonzini
2016-03-23 10:45 ` Kevin Wolf
2016-03-23 11:07 ` Paolo Bonzini
2016-03-16 14:16 ` [Qemu-devel] [PATCH v2 12/16] aio: introduce aio_context_in_iothread Paolo Bonzini
2016-03-16 14:16 ` [Qemu-devel] [PATCH v2 13/16] block: only call aio_poll from iothread Paolo Bonzini
2016-03-16 14:16 ` [Qemu-devel] [PATCH v2 14/16] iothread: release AioContext around aio_poll Paolo Bonzini
2016-03-16 14:16 ` [Qemu-devel] [PATCH v2 15/16] qemu-thread: introduce QemuRecMutex Paolo Bonzini
2016-03-16 14:16 ` [Qemu-devel] [PATCH v2 16/16] aio: convert from RFifoLock to QemuRecMutex Paolo Bonzini
2016-03-18 16:03 ` [Qemu-devel] [PATCH v2 00/16] AioContext fine-grained locking, part 1 of 3, including bdrv_drain rewrite Stefan Hajnoczi
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