From patchwork Fri Jan 28 11:50:13 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Emanuele Giuseppe Esposito X-Patchwork-Id: 1585638 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: bilbo.ozlabs.org; dkim=fail reason="signature verification failed" (1024-bit key; unprotected) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256 header.s=mimecast20190719 header.b=KCawuHv7; dkim-atps=neutral Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org (client-ip=209.51.188.17; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=) 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 bilbo.ozlabs.org (Postfix) with ESMTPS id 4JlbcR2bFhz9t56 for ; Fri, 28 Jan 2022 23:00:07 +1100 (AEDT) Received: from localhost ([::1]:46516 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1nDPvB-00084D-3C for incoming@patchwork.ozlabs.org; Fri, 28 Jan 2022 07:00:05 -0500 Received: from eggs.gnu.org ([209.51.188.92]:60364) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nDPm8-0004WH-2U for qemu-devel@nongnu.org; Fri, 28 Jan 2022 06:50:45 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:57513) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nDPm5-0003Nu-Lj for qemu-devel@nongnu.org; Fri, 28 Jan 2022 06:50:43 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1643370640; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=qxcJppvwnYVfQdCihPNsBkAfFi8EBTfnO0Mo6JSswdc=; b=KCawuHv75oggyJpLlHQ61/ktCYhJGirhmRYUQt+pBc6CvtQuk7YR4OfmDbnUXkbMTl3nf5 xM+Dcue3iMOgTJaXfFT3fD4kFJsMErxBy3hfZxKv6BjpnJse+USuwto8YLKep4xB6Lj5sh oJKvgTuL1EXMHVNxbnvDesO2HrGwHNI= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-448-J8omojhQMtC1cnyHRANLXQ-1; Fri, 28 Jan 2022 06:50:37 -0500 X-MC-Unique: J8omojhQMtC1cnyHRANLXQ-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 61CFD1006AA6; Fri, 28 Jan 2022 11:50:36 +0000 (UTC) Received: from virtlab701.virt.lab.eng.bos.redhat.com (virtlab701.virt.lab.eng.bos.redhat.com [10.19.152.228]) by smtp.corp.redhat.com (Postfix) with ESMTP id 43FE122DE7; Fri, 28 Jan 2022 11:50:34 +0000 (UTC) From: Emanuele Giuseppe Esposito To: qemu-block@nongnu.org Subject: [PATCH v4 01/19] job.c: make job_mutex and job_lock/unlock() public Date: Fri, 28 Jan 2022 06:50:13 -0500 Message-Id: <20220128115031.4061565-2-eesposit@redhat.com> In-Reply-To: <20220128115031.4061565-1-eesposit@redhat.com> References: <20220128115031.4061565-1-eesposit@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=eesposit@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Received-SPF: pass client-ip=170.10.133.124; envelope-from=eesposit@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -29 X-Spam_score: -3.0 X-Spam_bar: --- X-Spam_report: (-3.0 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.167, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 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: , Cc: Kevin Wolf , Fam Zheng , Vladimir Sementsov-Ogievskiy , Wen Congyang , Xie Changlong , Emanuele Giuseppe Esposito , Markus Armbruster , qemu-devel@nongnu.org, Hanna Reitz , Stefan Hajnoczi , Paolo Bonzini , John Snow Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" job mutex will be used to protect the job struct elements and list, replacing AioContext locks. Right now use a shared lock for all jobs, in order to keep things simple. Once the AioContext lock is gone, we can introduce per-job locks. To simplify the switch from aiocontext to job lock, introduce *nop* lock/unlock functions and macros. We want to always call job_lock/unlock outside the AioContext locks, and not vice-versa, otherwise we might get a deadlock. This is not straightforward to do, and that's why we start with nop functions. Once everything is protected by job_lock/unlock, we can change the nop into an actual mutex and remove the aiocontext lock. Since job_mutex is already being used, add static real_job_{lock/unlock} for the existing usage. Signed-off-by: Emanuele Giuseppe Esposito --- include/qemu/job.h | 24 ++++++++++++++++++++++++ job.c | 35 +++++++++++++++++++++++------------ 2 files changed, 47 insertions(+), 12 deletions(-) diff --git a/include/qemu/job.h b/include/qemu/job.h index 915ceff425..8d0d370dda 100644 --- a/include/qemu/job.h +++ b/include/qemu/job.h @@ -312,6 +312,30 @@ typedef enum JobCreateFlags { JOB_MANUAL_DISMISS = 0x04, } JobCreateFlags; +extern QemuMutex job_mutex; + +#define JOB_LOCK_GUARD() /* QEMU_LOCK_GUARD(&job_mutex) */ + +#define WITH_JOB_LOCK_GUARD() /* WITH_QEMU_LOCK_GUARD(&job_mutex) */ + +/** + * job_lock: + * + * Take the mutex protecting the list of jobs and their status. + * Most functions called by the monitor need to call job_lock + * and job_unlock manually. On the other hand, function called + * by the block jobs themselves and by the block layer will take the + * lock for you. + */ +void job_lock(void); + +/** + * job_unlock: + * + * Release the mutex protecting the list of jobs and their status. + */ +void job_unlock(void); + /** * Allocate and return a new job transaction. Jobs can be added to the * transaction using job_txn_add_job(). diff --git a/job.c b/job.c index cf0dc9325a..f5e5b04e8c 100644 --- a/job.c +++ b/job.c @@ -32,6 +32,12 @@ #include "trace/trace-root.h" #include "qapi/qapi-events-job.h" +/* + * job_mutex protects the jobs list, but also makes the + * struct job fields thread-safe. + */ +QemuMutex job_mutex; + static QLIST_HEAD(, Job) jobs = QLIST_HEAD_INITIALIZER(jobs); /* Job State Transition Table */ @@ -74,17 +80,22 @@ struct JobTxn { int refcnt; }; -/* Right now, this mutex is only needed to synchronize accesses to job->busy - * and job->sleep_timer, such as concurrent calls to job_do_yield and - * job_enter. */ -static QemuMutex job_mutex; +void job_lock(void) +{ + /* nop */ +} + +void job_unlock(void) +{ + /* nop */ +} -static void job_lock(void) +static void real_job_lock(void) { qemu_mutex_lock(&job_mutex); } -static void job_unlock(void) +static void real_job_unlock(void) { qemu_mutex_unlock(&job_mutex); } @@ -450,21 +461,21 @@ void job_enter_cond(Job *job, bool(*fn)(Job *job)) return; } - job_lock(); + real_job_lock(); if (job->busy) { - job_unlock(); + real_job_unlock(); return; } if (fn && !fn(job)) { - job_unlock(); + real_job_unlock(); return; } assert(!job->deferred_to_main_loop); timer_del(&job->sleep_timer); job->busy = true; - job_unlock(); + real_job_unlock(); aio_co_enter(job->aio_context, job->co); } @@ -481,13 +492,13 @@ void job_enter(Job *job) * called explicitly. */ static void coroutine_fn job_do_yield(Job *job, uint64_t ns) { - job_lock(); + real_job_lock(); if (ns != -1) { timer_mod(&job->sleep_timer, ns); } job->busy = false; job_event_idle(job); - job_unlock(); + real_job_unlock(); qemu_coroutine_yield(); /* Set by job_enter_cond() before re-entering the coroutine. */