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[149.6.153.187]) by smtp.gmail.com with ESMTPSA id s20sm4270687wmb.9.2017.01.13.05.17.41 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 13 Jan 2017 05:17:41 -0800 (PST) From: Paolo Bonzini To: qemu-devel@nongnu.org Date: Fri, 13 Jan 2017 14:17:24 +0100 Message-Id: <20170113131731.1246-10-pbonzini@redhat.com> X-Mailer: git-send-email 2.9.3 In-Reply-To: <20170113131731.1246-1-pbonzini@redhat.com> References: <20170113131731.1246-1-pbonzini@redhat.com> X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 2a00:1450:400c:c09::242 Subject: [Qemu-devel] [PATCH 09/16] aio: push aio_context_acquire/release down to dispatching X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: famz@redhat.com, stefanha@redhat.com Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" The AioContext data structures are now protected by list_lock and/or they are walked with FOREACH_RCU primitives. There is no need anymore to acquire the AioContext for the entire duration of aio_dispatch. Instead, just acquire it before and after invoking the callbacks. The next step is then to push it further down. Reviewed-by: Stefan Hajnoczi Signed-off-by: Paolo Bonzini Reviewed-by: Stefan Hajnoczi --- aio-posix.c | 25 +++++++++++-------------- aio-win32.c | 15 +++++++-------- async.c | 2 ++ 3 files changed, 20 insertions(+), 22 deletions(-) diff --git a/aio-posix.c b/aio-posix.c index 9453d83..3fd64fb 100644 --- a/aio-posix.c +++ b/aio-posix.c @@ -402,7 +402,9 @@ static bool aio_dispatch_handlers(AioContext *ctx) (revents & (G_IO_IN | G_IO_HUP | G_IO_ERR)) && aio_node_check(ctx, node->is_external) && node->io_read) { + aio_context_acquire(ctx); node->io_read(node->opaque); + aio_context_release(ctx); /* aio_notify() does not count as progress */ if (node->opaque != &ctx->notifier) { @@ -413,7 +415,9 @@ static bool aio_dispatch_handlers(AioContext *ctx) (revents & (G_IO_OUT | G_IO_ERR)) && aio_node_check(ctx, node->is_external) && node->io_write) { + aio_context_acquire(ctx); node->io_write(node->opaque); + aio_context_release(ctx); progress = true; } @@ -450,7 +454,9 @@ bool aio_dispatch(AioContext *ctx, bool dispatch_fds) } /* Run our timers */ + aio_context_acquire(ctx); progress |= timerlistgroup_run_timers(&ctx->tlg); + aio_context_release(ctx); return progress; } @@ -596,9 +602,6 @@ bool aio_poll(AioContext *ctx, bool blocking) int64_t timeout; int64_t start = 0; - aio_context_acquire(ctx); - progress = false; - /* aio_notify can avoid the expensive event_notifier_set if * everything (file descriptors, bottom halves, timers) will * be re-evaluated before the next blocking poll(). This is @@ -616,9 +619,11 @@ bool aio_poll(AioContext *ctx, bool blocking) start = qemu_clock_get_ns(QEMU_CLOCK_REALTIME); } - if (try_poll_mode(ctx, blocking)) { - progress = true; - } else { + aio_context_acquire(ctx); + progress = try_poll_mode(ctx, blocking); + aio_context_release(ctx); + + if (!progress) { assert(npfd == 0); /* fill pollfds */ @@ -635,9 +640,6 @@ bool aio_poll(AioContext *ctx, bool blocking) timeout = blocking ? aio_compute_timeout(ctx) : 0; /* wait until next event */ - if (timeout) { - aio_context_release(ctx); - } if (aio_epoll_check_poll(ctx, pollfds, npfd, timeout)) { AioHandler epoll_handler; @@ -649,9 +651,6 @@ bool aio_poll(AioContext *ctx, bool blocking) } else { ret = qemu_poll_ns(pollfds, npfd, timeout); } - if (timeout) { - aio_context_acquire(ctx); - } } if (blocking) { @@ -716,8 +715,6 @@ bool aio_poll(AioContext *ctx, bool blocking) progress = true; } - aio_context_release(ctx); - return progress; } diff --git a/aio-win32.c b/aio-win32.c index 900524c..ab6d0e5 100644 --- a/aio-win32.c +++ b/aio-win32.c @@ -266,7 +266,9 @@ static bool aio_dispatch_handlers(AioContext *ctx, HANDLE event) (revents || event_notifier_get_handle(node->e) == event) && node->io_notify) { node->pfd.revents = 0; + aio_context_acquire(ctx); node->io_notify(node->e); + aio_context_release(ctx); /* aio_notify() does not count as progress */ if (node->e != &ctx->notifier) { @@ -278,11 +280,15 @@ static bool aio_dispatch_handlers(AioContext *ctx, HANDLE event) (node->io_read || node->io_write)) { node->pfd.revents = 0; if ((revents & G_IO_IN) && node->io_read) { + aio_context_acquire(ctx); node->io_read(node->opaque); + aio_context_release(ctx); progress = true; } if ((revents & G_IO_OUT) && node->io_write) { + aio_context_acquire(ctx); node->io_write(node->opaque); + aio_context_release(ctx); progress = true; } @@ -329,7 +335,6 @@ bool aio_poll(AioContext *ctx, bool blocking) int count; int timeout; - aio_context_acquire(ctx); progress = false; /* aio_notify can avoid the expensive event_notifier_set if @@ -371,17 +376,11 @@ bool aio_poll(AioContext *ctx, bool blocking) timeout = blocking && !have_select_revents ? qemu_timeout_ns_to_ms(aio_compute_timeout(ctx)) : 0; - if (timeout) { - aio_context_release(ctx); - } ret = WaitForMultipleObjects(count, events, FALSE, timeout); if (blocking) { assert(first); atomic_sub(&ctx->notify_me, 2); } - if (timeout) { - aio_context_acquire(ctx); - } if (first) { aio_notify_accept(ctx); @@ -404,8 +403,8 @@ bool aio_poll(AioContext *ctx, bool blocking) progress |= aio_dispatch_handlers(ctx, event); } while (count > 0); + aio_context_acquire(ctx); progress |= timerlistgroup_run_timers(&ctx->tlg); - aio_context_release(ctx); return progress; } diff --git a/async.c b/async.c index 1338682..ccb70e7 100644 --- a/async.c +++ b/async.c @@ -113,7 +113,9 @@ int aio_bh_poll(AioContext *ctx) ret = 1; } bh->idle = 0; + aio_context_acquire(ctx); aio_bh_call(bh); + aio_context_release(ctx); } if (bh->deleted) { deleted = true;