From patchwork Fri Jan 20 16:43:20 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paolo Bonzini X-Patchwork-Id: 717814 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [IPv6:2001:4830:134:3::11]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 3v4n9n6gpwz9s2s for ; Sat, 21 Jan 2017 04:04:13 +1100 (AEDT) Received: from localhost ([::1]:56053 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cUcbj-0003TG-Gd for incoming@patchwork.ozlabs.org; Fri, 20 Jan 2017 12:04:11 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:45465) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cUcI1-0003JG-97 for qemu-devel@nongnu.org; Fri, 20 Jan 2017 11:43:54 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cUcHx-0003Hi-UT for qemu-devel@nongnu.org; Fri, 20 Jan 2017 11:43:49 -0500 Received: from mx1.redhat.com ([209.132.183.28]:56788) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1cUcHx-0003Gk-MJ for qemu-devel@nongnu.org; Fri, 20 Jan 2017 11:43:45 -0500 Received: from int-mx13.intmail.prod.int.phx2.redhat.com (int-mx13.intmail.prod.int.phx2.redhat.com [10.5.11.26]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id D2C7E8046E for ; Fri, 20 Jan 2017 16:43:45 +0000 (UTC) Received: from donizetti.redhat.com (ovpn-117-138.ams2.redhat.com [10.36.117.138]) by int-mx13.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id v0KGhNCi020161; Fri, 20 Jan 2017 11:43:44 -0500 From: Paolo Bonzini To: qemu-devel@nongnu.org Date: Fri, 20 Jan 2017 17:43:20 +0100 Message-Id: <20170120164322.21851-16-pbonzini@redhat.com> In-Reply-To: <20170120164322.21851-1-pbonzini@redhat.com> References: <20170120164322.21851-1-pbonzini@redhat.com> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.26 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.28]); Fri, 20 Jan 2017 16:43:45 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCH 15/17] aio-posix: partially inline aio_dispatch into aio_poll 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" This patch prepares for the removal of unnecessary lockcnt inc/dec pairs. Extract the dispatching loop for file descriptor handlers into a new function aio_dispatch_handlers, and then inline aio_dispatch into aio_poll. aio_dispatch can now become void. Reviewed-by: Stefan Hajnoczi Signed-off-by: Paolo Bonzini --- include/block/aio.h | 6 +----- util/aio-posix.c | 44 ++++++++++++++------------------------------ util/aio-win32.c | 13 ++++--------- util/async.c | 2 +- 4 files changed, 20 insertions(+), 45 deletions(-) diff --git a/include/block/aio.h b/include/block/aio.h index 614cbc6..677b6ff 100644 --- a/include/block/aio.h +++ b/include/block/aio.h @@ -310,12 +310,8 @@ 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 dispatch_fds); +void aio_dispatch(AioContext *ctx); /* Progress in completing AIO work to occur. This can issue new pending * aio as a result of executing I/O completion or bh callbacks. diff --git a/util/aio-posix.c b/util/aio-posix.c index 6beebcd..51e92b8 100644 --- a/util/aio-posix.c +++ b/util/aio-posix.c @@ -386,12 +386,6 @@ static bool aio_dispatch_handlers(AioContext *ctx) AioHandler *node, *tmp; bool progress = false; - /* - * We have to walk very carefully in case aio_set_fd_handler is - * called while we're walking. - */ - qemu_lockcnt_inc(&ctx->list_lock); - QLIST_FOREACH_SAFE_RCU(node, &ctx->aio_handlers, node, tmp) { int revents; @@ -426,33 +420,18 @@ static bool aio_dispatch_handlers(AioContext *ctx) } } - qemu_lockcnt_dec(&ctx->list_lock); return progress; } -/* - * 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) +void aio_dispatch(AioContext *ctx) { - bool progress; - - /* - * If there are callbacks left that have been queued, we need to call them. - * 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). - */ - progress = aio_bh_poll(ctx); + aio_bh_poll(ctx); - if (dispatch_fds) { - progress |= aio_dispatch_handlers(ctx); - } - - /* Run our timers */ - progress |= timerlistgroup_run_timers(&ctx->tlg); + qemu_lockcnt_inc(&ctx->list_lock); + aio_dispatch_handlers(ctx); + qemu_lockcnt_dec(&ctx->list_lock); - return progress; + timerlistgroup_run_timers(&ctx->tlg); } /* These thread-local variables are used only in a small part of aio_poll @@ -701,11 +680,16 @@ bool aio_poll(AioContext *ctx, bool blocking) npfd = 0; qemu_lockcnt_dec(&ctx->list_lock); - /* Run dispatch even if there were no readable fds to run timers */ - if (aio_dispatch(ctx, ret > 0)) { - progress = true; + progress |= aio_bh_poll(ctx); + + if (ret > 0) { + qemu_lockcnt_inc(&ctx->list_lock); + progress |= aio_dispatch_handlers(ctx); + qemu_lockcnt_dec(&ctx->list_lock); } + progress |= timerlistgroup_run_timers(&ctx->tlg); + return progress; } diff --git a/util/aio-win32.c b/util/aio-win32.c index 20b63ce..442a179 100644 --- a/util/aio-win32.c +++ b/util/aio-win32.c @@ -309,16 +309,11 @@ static bool aio_dispatch_handlers(AioContext *ctx, HANDLE event) return progress; } -bool aio_dispatch(AioContext *ctx, bool dispatch_fds) +void aio_dispatch(AioContext *ctx) { - bool progress; - - progress = aio_bh_poll(ctx); - if (dispatch_fds) { - progress |= aio_dispatch_handlers(ctx, INVALID_HANDLE_VALUE); - } - progress |= timerlistgroup_run_timers(&ctx->tlg); - return progress; + aio_bh_poll(ctx); + aio_dispatch_handlers(ctx, INVALID_HANDLE_VALUE); + timerlistgroup_run_timers(&ctx->tlg); } bool aio_poll(AioContext *ctx, bool blocking) diff --git a/util/async.c b/util/async.c index 99b9d7e..cc40735 100644 --- a/util/async.c +++ b/util/async.c @@ -258,7 +258,7 @@ aio_ctx_dispatch(GSource *source, AioContext *ctx = (AioContext *) source; assert(callback == NULL); - aio_dispatch(ctx, true); + aio_dispatch(ctx); return true; }