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Re: [Qemu-devel] [PATCH v2 for-2.6 4/5] aio-posix: Skip external nodes i
From: |
Kevin Wolf |
Subject: |
Re: [Qemu-devel] [PATCH v2 for-2.6 4/5] aio-posix: Skip external nodes in aio_dispatch |
Date: |
Fri, 22 Apr 2016 13:38:34 +0200 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
Am 22.04.2016 um 12:56 hat Fam Zheng geschrieben:
> aio_poll doesn't poll the external nodes so this should never be true,
> but aio_ctx_dispatch may get notified by the events from GSource. To
> make bdrv_drained_begin effective in main loop, we should check the
> is_external flag here too.
>
> This could result in a few busy polls because the fd is left unhandled,
> but the drained section is only transient and shouldn't be longer than
> one or two event loop iterations.
Are the busy polls because aio_ctx_check() calls aio_pending(), which
still returns true, even if only disabled AioHandlers are ready? If so,
should we just add the is_external check to aio_pending(), too?
Kevin
> Signed-off-by: Fam Zheng <address@hidden>
> ---
> aio-posix.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/aio-posix.c b/aio-posix.c
> index 7fd565f..a7c9304 100644
> --- a/aio-posix.c
> +++ b/aio-posix.c
> @@ -323,6 +323,7 @@ bool aio_dispatch(AioContext *ctx)
>
> if (!node->deleted &&
> (revents & (G_IO_IN | G_IO_HUP | G_IO_ERR)) &&
> + aio_node_check(ctx, node->is_external) &&
> node->io_read) {
> node->io_read(node->opaque);
>
> @@ -333,6 +334,7 @@ bool aio_dispatch(AioContext *ctx)
> }
> if (!node->deleted &&
> (revents & (G_IO_OUT | G_IO_ERR)) &&
> + aio_node_check(ctx, node->is_external) &&
> node->io_write) {
> node->io_write(node->opaque);
> progress = true;
> --
> 2.8.0
>
- [Qemu-devel] [PATCH v2 for-2.6 0/5] block: Fix assertion failure at mirror exit, Fam Zheng, 2016/04/22
- [Qemu-devel] [PATCH v2 for-2.6 1/5] iohandler: Introduce iohandler_get_aio_context, Fam Zheng, 2016/04/22
- [Qemu-devel] [PATCH v2 for-2.6 2/5] event-notifier: Add "is_external" parameter, Fam Zheng, 2016/04/22
- [Qemu-devel] [PATCH v2 for-2.6 3/5] virtio: Mark host notifiers as external, Fam Zheng, 2016/04/22
- [Qemu-devel] [PATCH v2 for-2.6 4/5] aio-posix: Skip external nodes in aio_dispatch, Fam Zheng, 2016/04/22
- Re: [Qemu-devel] [PATCH v2 for-2.6 4/5] aio-posix: Skip external nodes in aio_dispatch,
Kevin Wolf <=
- [Qemu-devel] [PATCH v2 for-2.6 5/5] mirror: Workaround for unexpected iohandler events during completion, Fam Zheng, 2016/04/22
- Re: [Qemu-devel] [PATCH v2 for-2.6 0/5] block: Fix assertion failure at mirror exit, Michael S. Tsirkin, 2016/04/22