From patchwork Thu Nov 4 14:53:21 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Emanuele Giuseppe Esposito X-Patchwork-Id: 12603329 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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id BE179C433F5 for ; Thu, 4 Nov 2021 14:58:18 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 2CCBE611C4 for ; Thu, 4 Nov 2021 14:58:18 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 2CCBE611C4 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=nongnu.org Received: from localhost ([::1]:54876 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mieC1-0002KG-Bb for qemu-devel@archiver.kernel.org; Thu, 04 Nov 2021 10:58:17 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:51190) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mie81-000389-8m for qemu-devel@nongnu.org; Thu, 04 Nov 2021 10:54:12 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]:28378) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mie7y-0006sS-Un for qemu-devel@nongnu.org; Thu, 04 Nov 2021 10:54:09 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1636037646; 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=r7ofFkHnExQPEdJ0ShEbR6dIWEJ0sNV5QRWGv2LCM4g=; b=L5c49Mutm0umE43dZC00qkubzgKb+MfVR3Pd+2WWizy/2Y2puNGt+JWF/1ynokGRgzLTip YDsiQf633iuOlGwPPCypmFcBPdclNVf0jfF6m/bzo5goI+zhuKoAeA7/n52zhlLILGlBs9 Doow6wRtlRQ9NbikLykVJ+uMck8/YtI= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-217-Uwf9X2dpOxOsddGABji-uw-1; Thu, 04 Nov 2021 10:54:03 -0400 X-MC-Unique: Uwf9X2dpOxOsddGABji-uw-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id D419F1923795; Thu, 4 Nov 2021 14:53:51 +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 B779E6418A; Thu, 4 Nov 2021 14:53:50 +0000 (UTC) From: Emanuele Giuseppe Esposito To: qemu-block@nongnu.org Subject: [RFC PATCH v2 01/14] job.c: make job_lock/unlock public Date: Thu, 4 Nov 2021 10:53:21 -0400 Message-Id: <20211104145334.1346363-2-eesposit@redhat.com> In-Reply-To: <20211104145334.1346363-1-eesposit@redhat.com> References: <20211104145334.1346363-1-eesposit@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 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=170.10.129.124; envelope-from=eesposit@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -33 X-Spam_score: -3.4 X-Spam_bar: --- X-Spam_report: (-3.4 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.648, 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_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, 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: , 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+qemu-devel=archiver.kernel.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. Once everything is protected by jobs, we can add the mutex and remove the aiocontext. Since job_mutex is already being used, add static _job_{lock/unlock}. Signed-off-by: Emanuele Giuseppe Esposito Reviewed-by: Stefan Hajnoczi --- include/qemu/job.h | 18 ++++++++++++++++++ job.c | 39 +++++++++++++++++++++++++++------------ 2 files changed, 45 insertions(+), 12 deletions(-) diff --git a/include/qemu/job.h b/include/qemu/job.h index 7e9e59f4b8..ccf7826426 100644 --- a/include/qemu/job.h +++ b/include/qemu/job.h @@ -297,6 +297,24 @@ typedef enum JobCreateFlags { JOB_MANUAL_DISMISS = 0x04, } JobCreateFlags; +/** + * 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 94b142684f..0e4dacf028 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. + */ +static QemuMutex job_mutex; + static QLIST_HEAD(, Job) jobs = QLIST_HEAD_INITIALIZER(jobs); /* Job State Transition Table */ @@ -74,17 +80,26 @@ 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; +#define JOB_LOCK_GUARD() /* QEMU_LOCK_GUARD(&job_mutex) */ + +#define WITH_JOB_LOCK_GUARD() /* WITH_QEMU_LOCK_GUARD(&job_mutex) */ + +void job_lock(void) +{ + /* nop */ +} + +void job_unlock(void) +{ + /* nop */ +} -static void job_lock(void) +static void _job_lock(void) { qemu_mutex_lock(&job_mutex); } -static void job_unlock(void) +static void _job_unlock(void) { qemu_mutex_unlock(&job_mutex); } @@ -449,21 +464,21 @@ void job_enter_cond(Job *job, bool(*fn)(Job *job)) return; } - job_lock(); + _job_lock(); if (job->busy) { - job_unlock(); + _job_unlock(); return; } if (fn && !fn(job)) { - job_unlock(); + _job_unlock(); return; } assert(!job->deferred_to_main_loop); timer_del(&job->sleep_timer); job->busy = true; - job_unlock(); + _job_unlock(); aio_co_enter(job->aio_context, job->co); } @@ -480,13 +495,13 @@ void job_enter(Job *job) * called explicitly. */ static void coroutine_fn job_do_yield(Job *job, uint64_t ns) { - job_lock(); + _job_lock(); if (ns != -1) { timer_mod(&job->sleep_timer, ns); } job->busy = false; job_event_idle(job); - job_unlock(); + _job_unlock(); qemu_coroutine_yield(); /* Set by job_enter_cond() before re-entering the coroutine. */