From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id E86EAC433FE for ; Thu, 13 Oct 2022 19:08:17 +0000 (UTC) Received: from localhost ([::1]:44410 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1oj3Z2-0004xy-DG for qemu-devel@archiver.kernel.org; Thu, 13 Oct 2022 15:08:16 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:55606) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oj3QY-0006L0-9h for qemu-devel@nongnu.org; Thu, 13 Oct 2022 14:59:30 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:27230) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oj3QW-00042s-Rr for qemu-devel@nongnu.org; Thu, 13 Oct 2022 14:59:30 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1665687568; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=oogAcoRLp/QWsr4CO7HP7wKYUqyqCTLVEVguGfP/s9g=; b=QAp80J75KG3AlUW/WTWomdxvkfDhy+e+23t0pnbLWIFGDrioMkjL8tyykcerhtzvvYPFej 6qzXDh9j6LNaQsB5Fx5oWssYJN2e8UhrMzqj00o57rlc0FDaLRT7+g6Dspiq1sa9bAtO1n X4ngOa/2gkiWnInBqe3Sp5KU+S8/wLE= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-488-NAZPW-cCN2Kk2eV1ZwllwA-1; Thu, 13 Oct 2022 14:59:22 -0400 X-MC-Unique: NAZPW-cCN2Kk2eV1ZwllwA-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.rdu2.redhat.com [10.11.54.5]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 0BDF33C138A6; Thu, 13 Oct 2022 18:59:22 +0000 (UTC) Received: from localhost (unknown [10.39.194.71]) by smtp.corp.redhat.com (Postfix) with ESMTP id 4C83B7AE5; Thu, 13 Oct 2022 18:59:21 +0000 (UTC) From: Stefan Hajnoczi To: qemu-devel@nongnu.org Cc: Fam Zheng , Markus Armbruster , Stefan Hajnoczi , Laurent Vivier , Marcel Apfelbaum , "Michael S. Tsirkin" , Wen Congyang , Kevin Wolf , =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= , Richard Henderson , David Hildenbrand , Hanna Reitz , Xie Changlong , Eduardo Habkost , qemu-block@nongnu.org, Eric Blake , John Snow , afaria@redhat.com, Jeff Cody , Yanan Wang , Paolo Bonzini , Raphael Norwitz , sgarzare@redhat.com, integration@gluster.org, Peter Xu , "Richard W.M. Jones" , Thomas Huth , Vladimir Sementsov-Ogievskiy , "Denis V. Lunev" Subject: [PATCH v7 01/13] coroutine: add flag to re-queue at front of CoQueue Date: Thu, 13 Oct 2022 14:58:56 -0400 Message-Id: <20221013185908.1297568-2-stefanha@redhat.com> In-Reply-To: <20221013185908.1297568-1-stefanha@redhat.com> References: <20221013185908.1297568-1-stefanha@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.1 on 10.11.54.5 Received-SPF: pass client-ip=170.10.133.124; envelope-from=stefanha@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" When a coroutine wakes up it may determine that it must re-queue. Normally coroutines are pushed onto the back of the CoQueue, but for fairness it may be necessary to push it onto the front of the CoQueue. Add a flag to specify that the coroutine should be pushed onto the front of the CoQueue. A later patch will use this to ensure fairness in the bounce buffer CoQueue used by the blkio BlockDriver. Signed-off-by: Stefan Hajnoczi --- include/qemu/coroutine.h | 15 +++++++++++++-- util/qemu-coroutine-lock.c | 9 +++++++-- 2 files changed, 20 insertions(+), 4 deletions(-) diff --git a/include/qemu/coroutine.h b/include/qemu/coroutine.h index aae33cce17..608fe45dcf 100644 --- a/include/qemu/coroutine.h +++ b/include/qemu/coroutine.h @@ -198,14 +198,25 @@ typedef struct CoQueue { */ void qemu_co_queue_init(CoQueue *queue); +typedef enum { + /* + * Enqueue at front instead of back. Use this to re-queue a request when + * its wait condition is not satisfied after being woken up. + */ + CO_QUEUE_WAIT_FRONT = 0x1, +} CoQueueWaitFlags; + /** * Adds the current coroutine to the CoQueue and transfers control to the * caller of the coroutine. The mutex is unlocked during the wait and * locked again afterwards. */ #define qemu_co_queue_wait(queue, lock) \ - qemu_co_queue_wait_impl(queue, QEMU_MAKE_LOCKABLE(lock)) -void coroutine_fn qemu_co_queue_wait_impl(CoQueue *queue, QemuLockable *lock); + qemu_co_queue_wait_impl(queue, QEMU_MAKE_LOCKABLE(lock), 0) +#define qemu_co_queue_wait_flags(queue, lock, flags) \ + qemu_co_queue_wait_impl(queue, QEMU_MAKE_LOCKABLE(lock), (flags)) +void coroutine_fn qemu_co_queue_wait_impl(CoQueue *queue, QemuLockable *lock, + CoQueueWaitFlags flags); /** * Removes the next coroutine from the CoQueue, and queue it to run after diff --git a/util/qemu-coroutine-lock.c b/util/qemu-coroutine-lock.c index 15c82d9348..45c6b57374 100644 --- a/util/qemu-coroutine-lock.c +++ b/util/qemu-coroutine-lock.c @@ -39,10 +39,15 @@ void qemu_co_queue_init(CoQueue *queue) QSIMPLEQ_INIT(&queue->entries); } -void coroutine_fn qemu_co_queue_wait_impl(CoQueue *queue, QemuLockable *lock) +void coroutine_fn qemu_co_queue_wait_impl(CoQueue *queue, QemuLockable *lock, + CoQueueWaitFlags flags) { Coroutine *self = qemu_coroutine_self(); - QSIMPLEQ_INSERT_TAIL(&queue->entries, self, co_queue_next); + if (flags & CO_QUEUE_WAIT_FRONT) { + QSIMPLEQ_INSERT_HEAD(&queue->entries, self, co_queue_next); + } else { + QSIMPLEQ_INSERT_TAIL(&queue->entries, self, co_queue_next); + } if (lock) { qemu_lockable_unlock(lock); -- 2.37.3