From patchwork Tue Aug 2 06:32:51 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Aneesh Kumar K.V" X-Patchwork-Id: 107844 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [140.186.70.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id A183EB7199 for ; Tue, 2 Aug 2011 16:33:15 +1000 (EST) Received: from localhost ([::1]:59784 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Qo8XO-0003hj-UB for incoming@patchwork.ozlabs.org; Tue, 02 Aug 2011 02:33:10 -0400 Received: from eggs.gnu.org ([140.186.70.92]:37873) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Qo8XK-0003hT-7E for qemu-devel@nongnu.org; Tue, 02 Aug 2011 02:33:07 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Qo8XJ-0007u1-8d for qemu-devel@nongnu.org; Tue, 02 Aug 2011 02:33:06 -0400 Received: from e23smtp03.au.ibm.com ([202.81.31.145]:55787) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Qo8XI-0007ol-Li for qemu-devel@nongnu.org; Tue, 02 Aug 2011 02:33:05 -0400 Received: from d23relay03.au.ibm.com (d23relay03.au.ibm.com [202.81.31.245]) by e23smtp03.au.ibm.com (8.14.4/8.13.1) with ESMTP id p726RjFb014640 for ; Tue, 2 Aug 2011 16:27:45 +1000 Received: from d23av04.au.ibm.com (d23av04.au.ibm.com [9.190.235.139]) by d23relay03.au.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id p726X11d1114140 for ; Tue, 2 Aug 2011 16:33:01 +1000 Received: from d23av04.au.ibm.com (loopback [127.0.0.1]) by d23av04.au.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id p726X0R3019603 for ; Tue, 2 Aug 2011 16:33:00 +1000 Received: from skywalker.in.ibm.com (skywalker.in.ibm.com [9.124.35.49]) by d23av04.au.ibm.com (8.14.4/8.13.1/NCO v10.0 AVin) with ESMTP id p726Wxm6019545; Tue, 2 Aug 2011 16:32:59 +1000 From: "Aneesh Kumar K.V" To: qemu-devel@nongnu.org, Kevin Wolf Date: Tue, 2 Aug 2011 12:02:51 +0530 Message-Id: <1312266771-28726-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> X-Mailer: git-send-email 1.7.4.1 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.6, seldom 2.4 (older, 4) X-Received-From: 202.81.31.145 Cc: aliguori@us.ibm.com, "Aneesh Kumar K.V" Subject: [Qemu-devel] [PATCH -V3] coroutine: Add CoRwlock support 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 Signed-off-by: Aneesh Kumar K.V --- qemu-coroutine-lock.c | 44 ++++++++++++++++++++++++++++++++++++++++++++ qemu-coroutine.h | 32 ++++++++++++++++++++++++++++++++ 2 files changed, 76 insertions(+), 0 deletions(-) diff --git a/qemu-coroutine-lock.c b/qemu-coroutine-lock.c index a80f437..2a385a3 100644 --- a/qemu-coroutine-lock.c +++ b/qemu-coroutine-lock.c @@ -115,3 +115,47 @@ void coroutine_fn qemu_co_mutex_unlock(CoMutex *mutex) trace_qemu_co_mutex_unlock_return(mutex, self); } + +void qemu_co_rwlock_init(CoRwlock *lock) +{ + memset(lock, 0, sizeof(*lock)); + qemu_co_queue_init(&lock->queue); +} + +void qemu_co_rwlock_rdlock(CoRwlock *lock) +{ + while (lock->writer) { + qemu_co_queue_wait(&lock->queue); + } + lock->reader++; +} + +void qemu_co_rwlock_unlock(CoRwlock *lock) +{ + assert(qemu_in_coroutine()); + if (lock->writer) { + lock->writer = false; + while (!qemu_co_queue_empty(&lock->queue)) { + /* + * Wakeup every body. This will include some + * writers too. + */ + qemu_co_queue_next(&lock->queue); + } + } else { + lock->reader--; + assert(lock->reader >= 0); + /* Wakeup only one waiting writer */ + if (!lock->reader) { + qemu_co_queue_next(&lock->queue); + } + } +} + +void qemu_co_rwlock_wrlock(CoRwlock *lock) +{ + while (lock->writer || lock->reader) { + qemu_co_queue_wait(&lock->queue); + } + lock->writer = true; +} diff --git a/qemu-coroutine.h b/qemu-coroutine.h index 2f2fd95..b8fc4f4 100644 --- a/qemu-coroutine.h +++ b/qemu-coroutine.h @@ -156,4 +156,36 @@ void coroutine_fn qemu_co_mutex_lock(CoMutex *mutex); */ void coroutine_fn qemu_co_mutex_unlock(CoMutex *mutex); +typedef struct CoRwlock { + bool writer; + int reader; + CoQueue queue; +} CoRwlock; + +/** + * Initialises a CoRwlock. This must be called before any other operation + * is used on the CoRwlock + */ +void qemu_co_rwlock_init(CoRwlock *lock); + +/** + * Read locks the CoRwlock. If the lock cannot be taken immediately because + * of a parallel writer, control is transferred to the caller of the current + * coroutine. + */ +void qemu_co_rwlock_rdlock(CoRwlock *lock); + +/** + * Write Locks the mutex. If the lock cannot be taken immediately because + * of a parallel reader, control is transferred to the caller of the current + * coroutine. + */ +void qemu_co_rwlock_wrlock(CoRwlock *lock); + +/** + * Unlocks the read/write lock and schedules the next coroutine that was + * waiting for this lock to be run. + */ +void qemu_co_rwlock_unlock(CoRwlock *lock); + #endif /* QEMU_COROUTINE_H */