From nobody Sat Feb 7 05:48:52 2026 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) client-ip=208.118.235.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zoho.com; spf=pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; Return-Path: Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) by mx.zohomail.com with SMTPS id 1494516223694517.5684120179675; Thu, 11 May 2017 08:23:43 -0700 (PDT) Received: from localhost ([::1]:48812 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1d8pwL-0005c5-30 for importer@patchew.org; Thu, 11 May 2017 11:23:41 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:42230) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1d8pIT-0001bp-EO for qemu-devel@nongnu.org; Thu, 11 May 2017 10:42:30 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1d8pIS-0004ET-HA for qemu-devel@nongnu.org; Thu, 11 May 2017 10:42:29 -0400 Received: from mx1.redhat.com ([209.132.183.28]:51462) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1d8pIO-0004AX-J7; Thu, 11 May 2017 10:42:24 -0400 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 88A4780088; Thu, 11 May 2017 14:42:23 +0000 (UTC) Received: from donizetti.redhat.com (ovpn-117-123.ams2.redhat.com [10.36.117.123]) by int-mx13.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id v4BEg9AB012159; Thu, 11 May 2017 10:42:22 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 88A4780088 Authentication-Results: ext-mx04.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx04.extmail.prod.ext.phx2.redhat.com; spf=pass smtp.mailfrom=pbonzini@redhat.com DKIM-Filter: OpenDKIM Filter v2.11.0 mx1.redhat.com 88A4780088 From: Paolo Bonzini To: qemu-devel@nongnu.org Date: Thu, 11 May 2017 16:41:59 +0200 Message-Id: <20170511144208.24075-10-pbonzini@redhat.com> In-Reply-To: <20170511144208.24075-1-pbonzini@redhat.com> References: <20170511144208.24075-1-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]); Thu, 11 May 2017 14:42:23 +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 09/18] throttle-groups: protect throttled requests with a CoMutex 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, qemu-block@nongnu.org, stefanha@redhat.com Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RSF_0 Z_629925259 SPT_0 Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Another possibility is to use tg->lock, which we're holding anyway in both schedule_next_request and throttle_group_co_io_limits_intercept. This would require open-coding the CoQueue however, so I've chosen this alternative. Signed-off-by: Paolo Bonzini Reviewed-by: Stefan Hajnoczi --- v1->v2: rename CoMutex [Fam] block/block-backend.c | 1 + block/throttle-groups.c | 12 ++++++++++-- include/sysemu/block-backend.h | 7 ++----- 3 files changed, 13 insertions(+), 7 deletions(-) diff --git a/block/block-backend.c b/block/block-backend.c index 915ccc5e56..17b0ef2dc3 100644 --- a/block/block-backend.c +++ b/block/block-backend.c @@ -163,6 +163,7 @@ BlockBackend *blk_new(uint64_t perm, uint64_t shared_pe= rm) blk->shared_perm =3D shared_perm; blk_set_enable_write_cache(blk, true); =20 + qemu_co_mutex_init(&blk->public.throttled_reqs_lock); qemu_co_queue_init(&blk->public.throttled_reqs[0]); qemu_co_queue_init(&blk->public.throttled_reqs[1]); =20 diff --git a/block/throttle-groups.c b/block/throttle-groups.c index 8bf1031efa..a181cb1dee 100644 --- a/block/throttle-groups.c +++ b/block/throttle-groups.c @@ -270,8 +270,13 @@ static bool coroutine_fn throttle_group_co_restart_que= ue(BlockBackend *blk, bool is_write) { BlockBackendPublic *blkp =3D blk_get_public(blk); + bool ret; =20 - return qemu_co_queue_next(&blkp->throttled_reqs[is_write]); + qemu_co_mutex_lock(&blkp->throttled_reqs_lock); + ret =3D qemu_co_queue_next(&blkp->throttled_reqs[is_write]); + qemu_co_mutex_unlock(&blkp->throttled_reqs_lock); + + return ret; } =20 /* Look for the next pending I/O request and schedule it. @@ -340,7 +345,10 @@ void coroutine_fn throttle_group_co_io_limits_intercep= t(BlockBackend *blk, if (must_wait || blkp->pending_reqs[is_write]) { blkp->pending_reqs[is_write]++; qemu_mutex_unlock(&tg->lock); - qemu_co_queue_wait(&blkp->throttled_reqs[is_write], NULL); + qemu_co_mutex_lock(&blkp->throttled_reqs_lock); + qemu_co_queue_wait(&blkp->throttled_reqs[is_write], + &blkp->throttled_reqs_lock); + qemu_co_mutex_unlock(&blkp->throttled_reqs_lock); qemu_mutex_lock(&tg->lock); blkp->pending_reqs[is_write]--; } diff --git a/include/sysemu/block-backend.h b/include/sysemu/block-backend.h index 87a43b07ab..f8b7eaa4f2 100644 --- a/include/sysemu/block-backend.h +++ b/include/sysemu/block-backend.h @@ -72,11 +72,8 @@ typedef struct BlockDevOps { * fields that must be public. This is in particular for QLIST_ENTRY() and * friends so that BlockBackends can be kept in lists outside block-backen= d.c */ typedef struct BlockBackendPublic { - /* I/O throttling has its own locking, but also some fields are - * protected by the AioContext lock. - */ - - /* Protected by AioContext lock. */ + /* throttled_reqs_lock protects the CoQueues for throttled requests. = */ + CoMutex throttled_reqs_lock; CoQueue throttled_reqs[2]; =20 /* Nonzero if the I/O limits are currently being ignored; generally --=20 2.12.2