From nobody Mon Apr 29 07:38:14 2024 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) client-ip=208.118.235.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zohomail.com; spf=pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org Return-Path: Received: from lists.gnu.org (208.118.235.17 [208.118.235.17]) by mx.zohomail.com with SMTPS id 1513198626681625.4400740480369; Wed, 13 Dec 2017 12:57:06 -0800 (PST) Received: from localhost ([::1]:37632 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ePE5M-0005Hf-T1 for importer@patchew.org; Wed, 13 Dec 2017 15:57:00 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:39834) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ePDv9-00055f-6k for qemu-devel@nongnu.org; Wed, 13 Dec 2017 15:46:28 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ePDv8-0000Bn-6R for qemu-devel@nongnu.org; Wed, 13 Dec 2017 15:46:27 -0500 Received: from mx1.redhat.com ([209.132.183.28]:41562) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1ePDv3-0008TK-Ih; Wed, 13 Dec 2017 15:46:21 -0500 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id CC6F36A7CD; Wed, 13 Dec 2017 20:46:19 +0000 (UTC) Received: from probe.bos.redhat.com (dhcp-17-231.bos.redhat.com [10.18.17.231]) by smtp.corp.redhat.com (Postfix) with ESMTP id 54AF56A53F; Wed, 13 Dec 2017 20:46:12 +0000 (UTC) From: John Snow To: qemu-block@nongnu.org Date: Wed, 13 Dec 2017 15:46:11 -0500 Message-Id: <20171213204611.26276-1-jsnow@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.27]); Wed, 13 Dec 2017 20:46:19 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCH v2] blockjob: kick jobs on set-speed X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: kwolf@redhat.com, jcody@redhat.com, qemu-devel@nongnu.org, mreitz@redhat.com, stefanha@redhat.com, John Snow Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RSF_0 Z_629925259 SPT_0 Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" If users set an unreasonably low speed (like one byte per second), the calculated delay may exceed many hours. While we like to punish users for asking for stupid things, we do also like to allow users to correct their wicked ways. When a user provides a new speed, kick the job to allow it to recalculate its delay. Signed-off-by: John Snow Reviewed-by: Stefan Hajnoczi --- RFC: Why is block_job_mutex shared between all jobs, instead of being per-job? blockjob.c | 30 +++++++++++++++++++++++++++++- 1 file changed, 29 insertions(+), 1 deletion(-) diff --git a/blockjob.c b/blockjob.c index 715c2c2680..6173e4728c 100644 --- a/blockjob.c +++ b/blockjob.c @@ -59,6 +59,7 @@ static void __attribute__((__constructor__)) block_job_in= it(void) =20 static void block_job_event_cancelled(BlockJob *job); static void block_job_event_completed(BlockJob *job, const char *msg); +static void block_job_enter_cond(BlockJob *job, bool(*fn)(BlockJob *job)); =20 /* Transactional group of block jobs */ struct BlockJobTxn { @@ -480,9 +481,16 @@ static void block_job_completed_txn_success(BlockJob *= job) } } =20 +/* Assumes the block_job_mutex is held */ +static bool block_job_timer_pending(BlockJob *job) +{ + return timer_pending(&job->sleep_timer); +} + void block_job_set_speed(BlockJob *job, int64_t speed, Error **errp) { Error *local_err =3D NULL; + int64_t old_speed =3D job->speed; =20 if (!job->driver->set_speed) { error_setg(errp, QERR_UNSUPPORTED); @@ -495,6 +503,12 @@ void block_job_set_speed(BlockJob *job, int64_t speed,= Error **errp) } =20 job->speed =3D speed; + if (speed <=3D old_speed) { + return; + } + + /* kick only if a timer is pending */ + block_job_enter_cond(job, block_job_timer_pending); } =20 void block_job_complete(BlockJob *job, Error **errp) @@ -821,7 +835,11 @@ void block_job_resume_all(void) } } =20 -void block_job_enter(BlockJob *job) +/* + * Conditionally enter a block_job pending a call to fn() while + * under the block_job_lock critical section. + */ +static void block_job_enter_cond(BlockJob *job, bool(*fn)(BlockJob *job)) { if (!block_job_started(job)) { return; @@ -836,6 +854,11 @@ void block_job_enter(BlockJob *job) return; } =20 + if (fn && !fn(job)) { + block_job_unlock(); + return; + } + assert(!job->deferred_to_main_loop); timer_del(&job->sleep_timer); job->busy =3D true; @@ -843,6 +866,11 @@ void block_job_enter(BlockJob *job) aio_co_wake(job->co); } =20 +void block_job_enter(BlockJob *job) +{ + block_job_enter_cond(job, NULL); +} + bool block_job_is_cancelled(BlockJob *job) { return job->cancelled; --=20 2.14.3