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Re: [Qemu-devel] [PATCH 08/17] aio: add non-blocking variant of aio_wait
From: |
Anthony Liguori |
Subject: |
Re: [Qemu-devel] [PATCH 08/17] aio: add non-blocking variant of aio_wait |
Date: |
Tue, 25 Sep 2012 16:56:19 -0500 |
User-agent: |
Notmuch/0.13.2+93~ged93d79 (http://notmuchmail.org) Emacs/23.3.1 (x86_64-pc-linux-gnu) |
Paolo Bonzini <address@hidden> writes:
> This will be used when polling the GSource attached to an AioContext.
>
> Signed-off-by: Paolo Bonzini <address@hidden>
Reviewed-by: Anthony Liguori <address@hidden>
Regards,
Anthony Liguori
> ---
> aio.c | 16 ++++++++++++----
> async.c | 2 +-
> main-loop.c | 2 +-
> qemu-aio.h | 21 +++++++++++++++------
> 4 file modificati, 29 inserzioni(+), 12 rimozioni(-)
>
> diff --git a/aio.c b/aio.c
> index c89f1e9..95ad467 100644
> --- a/aio.c
> +++ b/aio.c
> @@ -93,13 +93,16 @@ void aio_set_event_notifier(AioContext *ctx,
> (AioFlushHandler *)io_flush, notifier);
> }
>
> -bool aio_wait(AioContext *ctx)
> +bool aio_poll(AioContext *ctx, bool blocking)
> {
> + static struct timeval tv0;
> AioHandler *node;
> fd_set rdfds, wrfds;
> int max_fd = -1;
> int ret;
> - bool busy;
> + bool busy, progress;
> +
> + progress = false;
>
> /*
> * If there are callbacks left that have been queued, we need to call
> then.
> @@ -107,6 +110,11 @@ bool aio_wait(AioContext *ctx)
> * does not need a complete flush (as is the case for qemu_aio_wait
> loops).
> */
> if (aio_bh_poll(ctx)) {
> + blocking = false;
> + progress = true;
> + }
> +
> + if (progress && !blocking) {
> return true;
> }
>
> @@ -142,11 +150,11 @@ bool aio_wait(AioContext *ctx)
>
> /* No AIO operations? Get us out of here */
> if (!busy) {
> - return false;
> + return progress;
> }
>
> /* wait until next event */
> - ret = select(max_fd, &rdfds, &wrfds, NULL, NULL);
> + ret = select(max_fd, &rdfds, &wrfds, NULL, blocking ? NULL : &tv0);
>
> /* if we have any readable fds, dispatch event */
> if (ret > 0) {
> diff --git a/async.c b/async.c
> index c99db79..513bdd7 100644
> --- a/async.c
> +++ b/async.c
> @@ -144,5 +144,5 @@ AioContext *aio_context_new(void)
>
> void aio_flush(AioContext *ctx)
> {
> - while (aio_wait(ctx));
> + while (aio_poll(ctx, true));
> }
> diff --git a/main-loop.c b/main-loop.c
> index 8301fe9..67800fe 100644
> --- a/main-loop.c
> +++ b/main-loop.c
> @@ -531,7 +531,7 @@ void qemu_aio_flush(void)
>
> bool qemu_aio_wait(void)
> {
> - return aio_wait(qemu_aio_context);
> + return aio_poll(qemu_aio_context, true);
> }
>
> void qemu_aio_set_fd_handler(int fd,
> diff --git a/qemu-aio.h b/qemu-aio.h
> index f8a93d8..f19201e 100644
> --- a/qemu-aio.h
> +++ b/qemu-aio.h
> @@ -133,13 +133,22 @@ void qemu_bh_delete(QEMUBH *bh);
> * outstanding AIO operations have been completed or cancelled. */
> void aio_flush(AioContext *ctx);
>
> -/* Wait for a single AIO completion to occur. This function will wait
> - * until a single AIO event has completed and it will ensure something
> - * has moved before returning. This can issue new pending aio as
> - * result of executing I/O completion or bh callbacks.
> +/* Progress in completing AIO work to occur. This can issue new pending
> + * aio as a result of executing I/O completion or bh callbacks.
> *
> - * Return whether there is still any pending AIO operation. */
> -bool aio_wait(AioContext *ctx);
> + * If there is no pending AIO operation or completion (bottom half),
> + * return false. If there are pending bottom halves, return true.
> + *
> + * If there are no pending bottom halves, but there are pending AIO
> + * operations, it may not be possible to make any progress without
> + * blocking. If @blocking is true, this function will wait until one
> + * or more AIO events have completed, to ensure something has moved
> + * before returning.
> + *
> + * If @blocking is false, this function will also return false if the
> + * function cannot make any progress without blocking.
> + */
> +bool aio_poll(AioContext *ctx, bool blocking);
>
> #ifdef CONFIG_POSIX
> /* Returns 1 if there are still outstanding AIO requests; 0 otherwise */
> --
> 1.7.12
- [Qemu-devel] [PATCH 02/17] event_notifier: enable it to use pipes, (continued)
- [Qemu-devel] [PATCH 02/17] event_notifier: enable it to use pipes, Paolo Bonzini, 2012/09/25
- [Qemu-devel] [PATCH 04/17] aio: change qemu_aio_set_fd_handler to return void, Paolo Bonzini, 2012/09/25
- [Qemu-devel] [PATCH 06/17] aio: introduce AioContext, move bottom halves there, Paolo Bonzini, 2012/09/25
- [Qemu-devel] [PATCH 05/17] aio: provide platform-independent API, Paolo Bonzini, 2012/09/25
- [Qemu-devel] [PATCH 07/17] aio: add I/O handlers to the AioContext interface, Paolo Bonzini, 2012/09/25
- [Qemu-devel] [PATCH 08/17] aio: add non-blocking variant of aio_wait, Paolo Bonzini, 2012/09/25
- Re: [Qemu-devel] [PATCH 08/17] aio: add non-blocking variant of aio_wait,
Anthony Liguori <=
- [Qemu-devel] [PATCH 10/17] aio: add Win32 implementation, Paolo Bonzini, 2012/09/25
- [Qemu-devel] [PATCH 09/17] aio: prepare for introducing GSource-based dispatch, Paolo Bonzini, 2012/09/25
- [Qemu-devel] [PATCH 12/17] aio: add aio_notify, Paolo Bonzini, 2012/09/25
- [Qemu-devel] [PATCH 13/17] aio: call aio_notify after setting I/O handlers, Paolo Bonzini, 2012/09/25