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| author | Stefan Hajnoczi <stefanha@redhat.com> | 2016-12-01 19:26:40 +0000 |
|---|---|---|
| committer | Stefan Hajnoczi <stefanha@redhat.com> | 2017-01-03 16:38:47 +0000 |
| commit | 721671ade77f4046b45893fbb7864ca84b9504cd (patch) | |
| tree | 46a5e927a01342c5818e6ba99f137a6ad6fbb9f8 | |
| parent | 0891ee111217101bce683e30ed9f08cf0cfcffd7 (diff) | |
| download | focaccia-qemu-721671ade77f4046b45893fbb7864ca84b9504cd.tar.gz focaccia-qemu-721671ade77f4046b45893fbb7864ca84b9504cd.zip | |
aio: add flag to skip fds to aio_dispatch()
Polling mode will not call ppoll(2)/epoll_wait(2). Therefore we know there are no fds ready and should avoid looping over fd handlers in aio_dispatch(). Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Message-id: 20161201192652.9509-2-stefanha@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
| -rw-r--r-- | aio-posix.c | 14 | ||||
| -rw-r--r-- | aio-win32.c | 6 | ||||
| -rw-r--r-- | async.c | 2 | ||||
| -rw-r--r-- | include/block/aio.h | 6 |
4 files changed, 20 insertions, 8 deletions
diff --git a/aio-posix.c b/aio-posix.c index e13b9ab2b0..4ac2346370 100644 --- a/aio-posix.c +++ b/aio-posix.c @@ -290,9 +290,13 @@ bool aio_pending(AioContext *ctx) return false; } -bool aio_dispatch(AioContext *ctx) +/* + * Note that dispatch_fds == false has the side-effect of post-poning the + * freeing of deleted handlers. + */ +bool aio_dispatch(AioContext *ctx, bool dispatch_fds) { - AioHandler *node; + AioHandler *node = NULL; bool progress = false; /* @@ -308,7 +312,9 @@ bool aio_dispatch(AioContext *ctx) * We have to walk very carefully in case aio_set_fd_handler is * called while we're walking. */ - node = QLIST_FIRST(&ctx->aio_handlers); + if (dispatch_fds) { + node = QLIST_FIRST(&ctx->aio_handlers); + } while (node) { AioHandler *tmp; int revents; @@ -473,7 +479,7 @@ bool aio_poll(AioContext *ctx, bool blocking) ctx->walking_handlers--; /* Run dispatch even if there were no readable fds to run timers */ - if (aio_dispatch(ctx)) { + if (aio_dispatch(ctx, ret > 0)) { progress = true; } diff --git a/aio-win32.c b/aio-win32.c index c8c249e260..3ef8ea4caa 100644 --- a/aio-win32.c +++ b/aio-win32.c @@ -271,12 +271,14 @@ static bool aio_dispatch_handlers(AioContext *ctx, HANDLE event) return progress; } -bool aio_dispatch(AioContext *ctx) +bool aio_dispatch(AioContext *ctx, bool dispatch_fds) { bool progress; progress = aio_bh_poll(ctx); - progress |= aio_dispatch_handlers(ctx, INVALID_HANDLE_VALUE); + if (dispatch_fds) { + progress |= aio_dispatch_handlers(ctx, INVALID_HANDLE_VALUE); + } progress |= timerlistgroup_run_timers(&ctx->tlg); return progress; } diff --git a/async.c b/async.c index b2de360c23..52bdb8fb39 100644 --- a/async.c +++ b/async.c @@ -251,7 +251,7 @@ aio_ctx_dispatch(GSource *source, AioContext *ctx = (AioContext *) source; assert(callback == NULL); - aio_dispatch(ctx); + aio_dispatch(ctx, true); return true; } diff --git a/include/block/aio.h b/include/block/aio.h index ca551e346f..c1519ec83a 100644 --- a/include/block/aio.h +++ b/include/block/aio.h @@ -295,8 +295,12 @@ bool aio_pending(AioContext *ctx); /* Dispatch any pending callbacks from the GSource attached to the AioContext. * * This is used internally in the implementation of the GSource. + * + * @dispatch_fds: true to process fds, false to skip them + * (can be used as an optimization by callers that know there + * are no fds ready) */ -bool aio_dispatch(AioContext *ctx); +bool aio_dispatch(AioContext *ctx, bool dispatch_fds); /* Progress in completing AIO work to occur. This can issue new pending * aio as a result of executing I/O completion or bh callbacks. |