From e4c7e2d12d7b1c4501ab3397218a206d4953e633 Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Wed, 9 Jul 2014 11:53:05 +0200 Subject: AioContext: export and use aio_dispatch So far, aio_poll's scheme was dispatch/poll/dispatch, where the first dispatch phase was used only in the GSource case in order to avoid a blocking poll. Earlier patches changed it to dispatch/prepare/poll/dispatch, where prepare is aio_compute_timeout. By making aio_dispatch public, we can remove the first dispatch phase altogether, so that both aio_poll and the GSource use the same prepare/poll/dispatch scheme. This patch breaks the invariant that aio_poll(..., true) will not block the first time it returns false. This used to be fundamental for qemu_aio_flush's implementation as "while (qemu_aio_wait()) {}" but no code in QEMU relies on this invariant anymore. The return value of aio_poll() is now comparable with that of g_main_context_iteration. Signed-off-by: Paolo Bonzini Signed-off-by: Stefan Hajnoczi --- aio-win32.c | 31 ++++--------------------------- 1 file changed, 4 insertions(+), 27 deletions(-) (limited to 'aio-win32.c') diff --git a/aio-win32.c b/aio-win32.c index 2ac38a897c..1ec434a83c 100644 --- a/aio-win32.c +++ b/aio-win32.c @@ -130,11 +130,12 @@ static bool aio_dispatch_handlers(AioContext *ctx, HANDLE event) return progress; } -static bool aio_dispatch(AioContext *ctx) +bool aio_dispatch(AioContext *ctx) { bool progress; - progress = aio_dispatch_handlers(ctx, INVALID_HANDLE_VALUE); + progress = aio_bh_poll(ctx); + progress |= aio_dispatch_handlers(ctx, INVALID_HANDLE_VALUE); progress |= timerlistgroup_run_timers(&ctx->tlg); return progress; } @@ -149,23 +150,6 @@ bool aio_poll(AioContext *ctx, bool blocking) progress = false; - /* - * If there are callbacks left that have been queued, we need to call then. - * Do not call select in this case, because it is possible that the caller - * does not need a complete flush (as is the case for aio_poll loops). - */ - if (aio_bh_poll(ctx)) { - blocking = false; - progress = true; - } - - /* Dispatch any pending callbacks from the GSource. */ - progress |= aio_dispatch(ctx); - - if (progress && !blocking) { - return true; - } - ctx->walking_handlers++; /* fill fd sets */ @@ -205,14 +189,7 @@ bool aio_poll(AioContext *ctx, bool blocking) events[ret - WAIT_OBJECT_0] = events[--count]; } - if (blocking) { - /* Run the timers a second time. We do this because otherwise aio_wait - * will not note progress - and will stop a drain early - if we have - * a timer that was not ready to run entering g_poll but is ready - * after g_poll. This will only do anything if a timer has expired. - */ - progress |= timerlistgroup_run_timers(&ctx->tlg); - } + progress |= timerlistgroup_run_timers(&ctx->tlg); return progress; } -- cgit v1.2.3