From patchwork Mon Jul 29 15:36:08 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Stefan Hajnoczi X-Patchwork-Id: 262825 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)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id 8DF232C00E1 for ; Tue, 30 Jul 2013 01:37:07 +1000 (EST) Received: from localhost ([::1]:42602 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1V3pVR-0006UA-4g for incoming@patchwork.ozlabs.org; Mon, 29 Jul 2013 11:37:05 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:51524) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1V3pUu-0006JM-B0 for qemu-devel@nongnu.org; Mon, 29 Jul 2013 11:36:37 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1V3pUp-0002cQ-BE for qemu-devel@nongnu.org; Mon, 29 Jul 2013 11:36:32 -0400 Received: from mx1.redhat.com ([209.132.183.28]:60023) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1V3pUp-0002cD-3m for qemu-devel@nongnu.org; Mon, 29 Jul 2013 11:36:27 -0400 Received: from int-mx11.intmail.prod.int.phx2.redhat.com (int-mx11.intmail.prod.int.phx2.redhat.com [10.5.11.24]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id r6TFaLHg018593 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Mon, 29 Jul 2013 11:36:21 -0400 Received: from localhost (ovpn-112-50.ams2.redhat.com [10.36.112.50]) by int-mx11.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id r6TFaJBL022455; Mon, 29 Jul 2013 11:36:20 -0400 From: Stefan Hajnoczi To: Date: Mon, 29 Jul 2013 17:36:08 +0200 Message-Id: <1375112172-24863-3-git-send-email-stefanha@redhat.com> In-Reply-To: <1375112172-24863-1-git-send-email-stefanha@redhat.com> References: <1375112172-24863-1-git-send-email-stefanha@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.68 on 10.5.11.24 X-MIME-Autoconverted: from 8bit to quoted-printable by mx1.redhat.com id r6TFaLHg018593 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x X-Received-From: 209.132.183.28 Cc: Anthony Liguori , =?UTF-8?q?Beno=C3=AEt=20Canet?= , Stefan Hajnoczi Subject: [Qemu-devel] [PATCH 2/6] block: Repair the throttling code. X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org From: Benoît Canet The throttling code was segfaulting since commit 02ffb504485f0920cfc75a0982a602f824a9a4f4 because some qemu_co_queue_next caller does not run in a coroutine. qemu_co_queue_do_restart assume that the caller is a coroutinne. As suggested by Stefan fix this by entering the coroutine directly. Also make sure like suggested that qemu_co_queue_next() and qemu_co_queue_restart_all() can be called only in coroutines. Signed-off-by: Benoit Canet Signed-off-by: Stefan Hajnoczi --- block.c | 7 +++---- include/block/coroutine.h | 9 +++++++-- qemu-coroutine-lock.c | 20 ++++++++++++++++++-- 3 files changed, 28 insertions(+), 8 deletions(-) diff --git a/block.c b/block.c index c77cfd1..01b66d8 100644 --- a/block.c +++ b/block.c @@ -127,7 +127,7 @@ void bdrv_io_limits_disable(BlockDriverState *bs) { bs->io_limits_enabled = false; - while (qemu_co_queue_next(&bs->throttled_reqs)); + do {} while (qemu_co_enter_next(&bs->throttled_reqs)); if (bs->block_timer) { qemu_del_timer(bs->block_timer); @@ -143,7 +143,7 @@ static void bdrv_block_timer(void *opaque) { BlockDriverState *bs = opaque; - qemu_co_queue_next(&bs->throttled_reqs); + qemu_co_enter_next(&bs->throttled_reqs); } void bdrv_io_limits_enable(BlockDriverState *bs) @@ -1452,8 +1452,7 @@ void bdrv_drain_all(void) * a busy wait. */ QTAILQ_FOREACH(bs, &bdrv_states, list) { - if (!qemu_co_queue_empty(&bs->throttled_reqs)) { - qemu_co_queue_restart_all(&bs->throttled_reqs); + while (qemu_co_enter_next(&bs->throttled_reqs)) { busy = true; } } diff --git a/include/block/coroutine.h b/include/block/coroutine.h index 377805a..1f2db3e 100644 --- a/include/block/coroutine.h +++ b/include/block/coroutine.h @@ -130,12 +130,17 @@ void coroutine_fn qemu_co_queue_wait_insert_head(CoQueue *queue); * * Returns true if a coroutine was restarted, false if the queue is empty. */ -bool qemu_co_queue_next(CoQueue *queue); +bool coroutine_fn qemu_co_queue_next(CoQueue *queue); /** * Restarts all coroutines in the CoQueue and leaves the queue empty. */ -void qemu_co_queue_restart_all(CoQueue *queue); +void coroutine_fn qemu_co_queue_restart_all(CoQueue *queue); + +/** + * Enter the next coroutine in the queue + */ +bool qemu_co_enter_next(CoQueue *queue); /** * Checks if the CoQueue is empty. diff --git a/qemu-coroutine-lock.c b/qemu-coroutine-lock.c index d9fea49..aeb33b9 100644 --- a/qemu-coroutine-lock.c +++ b/qemu-coroutine-lock.c @@ -88,16 +88,32 @@ static bool qemu_co_queue_do_restart(CoQueue *queue, bool single) return true; } -bool qemu_co_queue_next(CoQueue *queue) +bool coroutine_fn qemu_co_queue_next(CoQueue *queue) { + assert(qemu_in_coroutine()); return qemu_co_queue_do_restart(queue, true); } -void qemu_co_queue_restart_all(CoQueue *queue) +void coroutine_fn qemu_co_queue_restart_all(CoQueue *queue) { + assert(qemu_in_coroutine()); qemu_co_queue_do_restart(queue, false); } +bool qemu_co_enter_next(CoQueue *queue) +{ + Coroutine *next; + + next = QTAILQ_FIRST(&queue->entries); + if (!next) { + return false; + } + + QTAILQ_REMOVE(&queue->entries, next, co_queue_next); + qemu_coroutine_enter(next, NULL); + return true; +} + bool qemu_co_queue_empty(CoQueue *queue) { return (QTAILQ_FIRST(&queue->entries) == NULL);