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From: Charlie Shepherd <charlie@ctshepherd.com>
To: Stefan Hajnoczi <stefanha@gmail.com>
Cc: kwolf@redhat.com, pbonzini@redhat.com, gabriel@kerneis.info,
	qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [RFC v2 05/15] Make qcow2_open synchronous
Date: Thu, 29 Aug 2013 13:43:02 +0100	[thread overview]
Message-ID: <521F41D6.6050204@ctshepherd.com> (raw)
In-Reply-To: <20130829123345.GC17744@stefanha-thinkpad.redhat.com>

On 29/08/2013 13:33, Stefan Hajnoczi wrote:
> On Fri, Aug 09, 2013 at 07:43:55PM +0200, Charlie Shepherd wrote:
>> The previous patch convert all .bdrv_open functions to run from a coroutine context. However
>> qcow2's open method is also called from qcow2_invalidate_cache. bdrv_invalidate_cache is mainly
>> called by migration.c, which doesn't run in coroutine context, so rather than propagating
>> coroutine_fn annotations up the call chain, turn qcow2_open into a synchronous wrapper.
> I think it would be cleaner to make .bdrv_open a coroutine function and
> push the synchronous wrapper out to the callers.  That way we can either
> keep synchronous wrappers where necessary, or we can eventually convert
> that synchronous code to coroutine code.
>
> If you hide the synchronous wrapper inside qcow2 it blocks coroutine
> callers who could otherwise use the event loop.

So you want this approach for all synchronous wrappers?


Charlie

  reply	other threads:[~2013-08-29 12:43 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-08-09 17:43 [Qemu-devel] [RFC v2 01/15] Add an explanation of when a function should be marked coroutine_fn Charlie Shepherd
2013-08-09 17:43 ` [Qemu-devel] [RFC v2 02/15] Rename qemu_coroutine_self to qemu_coroutine_self_int and add an annotated wrapper Charlie Shepherd
2013-08-14 14:21   ` Stefan Hajnoczi
2013-08-09 17:43 ` [Qemu-devel] [RFC v2 03/15] Explicitly mark BlockDriver function .bdrv_create as coroutine and rename it bdrv_co_create Charlie Shepherd
2013-08-14 14:26   ` Stefan Hajnoczi
2013-08-09 17:43 ` [Qemu-devel] [RFC v2 04/15] Convert .bdrv_open and .bdrv_file_open to coroutine_fn Charlie Shepherd
2013-08-29 12:11   ` Stefan Hajnoczi
2013-08-29 12:16     ` Charlie Shepherd
2013-08-09 17:43 ` [Qemu-devel] [RFC v2 05/15] Make qcow2_open synchronous Charlie Shepherd
2013-08-29 12:29   ` Stefan Hajnoczi
2013-08-29 12:33   ` Stefan Hajnoczi
2013-08-29 12:43     ` Charlie Shepherd [this message]
2013-09-04 11:39       ` Stefan Hajnoczi
2013-08-09 17:43 ` [Qemu-devel] [RFC v2 06/15] Explicitly mark BlockDriver functions .bdrv_write and .bdrv_read as coroutine functions Charlie Shepherd
2013-08-09 17:43 ` [Qemu-devel] [RFC v2 07/15] Call bdrv->open via a synchronous wrapper in block/snapshot.c Charlie Shepherd
2013-08-29 15:14   ` Stefan Hajnoczi
2013-08-09 17:43 ` [Qemu-devel] [RFC v2 08/15] Convert bdrv_create and associated functions to be coroutine_fn Charlie Shepherd
2013-08-29 15:31   ` Stefan Hajnoczi
2013-08-09 17:43 ` [Qemu-devel] [RFC v2 09/15] Add a synchronous wrapper bdrv_sync_rwco Charlie Shepherd
2013-08-29 15:32   ` Stefan Hajnoczi
2013-08-09 17:44 ` [Qemu-devel] [RFC v2 10/15] Convert bdrv_read, bdrv_write and associated functions to coroutine functions Charlie Shepherd
2013-08-09 17:44 ` [Qemu-devel] [RFC v2 11/15] Make bdrv_discard coroutine only and add bdrv_sync_discard Charlie Shepherd
2013-08-09 17:44 ` [Qemu-devel] [RFC v2 12/15] Make bdrv_flush coroutine only and add bdrv_sync_flush Charlie Shepherd
2013-08-09 17:44 ` [Qemu-devel] [RFC v2 13/15] Introduce a run_handler function in qemu-img.c Charlie Shepherd
2013-08-09 17:44 ` [Qemu-devel] [RFC v2 14/15] Add coroutine annotations for qemu_co_rwlock_rdlock and qemu_co_rwlock_wrlock Charlie Shepherd
2013-08-09 17:44 ` [Qemu-devel] [RFC v2 15/15] Add coroutine_fn annotations to nbd_co_* functions Charlie Shepherd
2013-08-14 14:14 ` [Qemu-devel] [RFC v2 01/15] Add an explanation of when a function should be marked coroutine_fn Stefan Hajnoczi
2013-08-29 15:34 ` Stefan Hajnoczi

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