From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from m16.mail.126.com (m16.mail.126.com [220.197.31.6]) by smtp.subspace.kernel.org (Postfix) with ESMTP id B0C091EE031 for ; Wed, 8 Jan 2025 11:03:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=220.197.31.6 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1736334211; cv=none; b=uRDC0RFOPhhJine5SXIa4Zr7CAtg0WfjnfDsW9ppgh3Plgc8uyAbQ1xhjLG2hCcFJhlrkS4SFybn0ZmhIGN52u/oGHsTXI9R6U29SBjy9B5+NdkP/uf5xZz2TD2HKk5LeyJGHudyuOibxREbhbQdUwV3TD0KdbC1ve74dF8LGb8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1736334211; c=relaxed/simple; bh=BMMql2ECsMDKBw0GRKYDjQHNI3uD3wRkCF+7ZfWnF3s=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=Ak6/WyPiYE7cmUBmS4eRAUGL6/jPIqv2sN7eA8GcJ33Lw3rXm6YYOMFXrTO9CNnS0emf+8LLuEYVIdIdpnPHeB+ZAzaNjHoOdB65HmN3FmJEO7tmPgmwCeLyK+9rAt+6+TUjsnI3Y4MBtYPdl9B8qX3xHAuDs43JuJsiW8fXz/M= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=126.com; spf=pass smtp.mailfrom=126.com; dkim=pass (1024-bit key) header.d=126.com header.i=@126.com header.b=BdtfqJrr; arc=none smtp.client-ip=220.197.31.6 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=126.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=126.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=126.com header.i=@126.com header.b="BdtfqJrr" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=126.com; s=s110527; h=Message-ID:Date:MIME-Version:Subject:From: Content-Type; bh=QSiidwp+qKK06STSwZmMHBu4kP55NmFbcxCA3echJzU=; b=BdtfqJrrAOX0c/8U8AXnlyDKIHUqk4621cdQ7Fifuw3/JRcZeoGgN8fGUmdvXN whhC8sjaM8lYaHUkCbDl2WYZ/Jv7oa8ENvO75K/BGaX34HkfCKKNbxRhCd/rpf+2 OzXJALURh7iKKPxKl6wqqKBpSSfW7AXCNQVwBnrvPNrzk= Received: from [172.24.148.16] (unknown []) by gzga-smtp-mtada-g0-1 (Coremail) with SMTP id _____wD3X6vcWn5nnmijAw--.25113S2; Wed, 08 Jan 2025 19:00:45 +0800 (CST) Message-ID: <1164966b-edae-470a-b36b-b08d952d897b@126.com> Date: Wed, 8 Jan 2025 19:00:43 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2] sched_ext: switch class when preempted by higher priority scheduler To: Andrea Righi Cc: tj@kernel.org, void@manifault.com, changwoo@igalia.com, mingo@redhat.com, peterz@infradead.org, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, vschneid@redhat.com, linux-kernel@vger.kernel.org References: <20250108023328.37675-1-jameshongleiwang@126.com> Content-Language: en-US From: Honglei Wang In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-CM-TRANSID:_____wD3X6vcWn5nnmijAw--.25113S2 X-Coremail-Antispam: 1Uf129KBjvJXoW7tw1UGF13trWfJFy8JryxXwb_yoW8XFW7pa ykZFy0ka12ya15K3WIvrn3uFyfWws7Ga4Sgr1Uta1ftF90gFyYqF95Kr4a9rWrCr109w1S vF4qvayaqr1jyaDanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x07UtpnQUUUUU= X-CM-SenderInfo: 5mdpv2pkrqwzphlzt0bj6rjloofrz/1tbiJA-OrWd+R8HdtwADs+ On 2025/1/8 17:05, Andrea Righi wrote: > Hi Honglei, > > On Wed, Jan 08, 2025 at 10:33:28AM +0800, Honglei Wang wrote: >> ops.cpu_release() function, if defined, must be invoked when preempted by >> a higher priority scheduler class task. This scenario was skipped in >> commit f422316d7466 ("sched_ext: Remove switch_class_scx()"). Let's fix >> it. >> >> Fixes: f422316d7466 ("sched_ext: Remove switch_class_scx()") >> Signed-off-by: Honglei Wang > > Thanks a lot for catching this, I've also reproduced a stall (due to the > missing ops.cpu_release() invocation) and verified that your fixes resolve > the problem, so: > > Acked-by: Andrea Righi > Thanks a lot for looking at the code and the test, Andrea. >> --- >> kernel/sched/ext.c | 3 ++- >> 1 file changed, 2 insertions(+), 1 deletion(-) >> >> diff --git a/kernel/sched/ext.c b/kernel/sched/ext.c >> index 19d2699cf638..ef0e3f2c1e6f 100644 >> --- a/kernel/sched/ext.c >> +++ b/kernel/sched/ext.c >> @@ -3034,7 +3034,7 @@ static void put_prev_task_scx(struct rq *rq, struct task_struct *p, >> */ >> if (p->scx.slice && !scx_rq_bypassing(rq)) { >> dispatch_enqueue(&rq->scx.local_dsq, p, SCX_ENQ_HEAD); >> - return; >> + goto switch_class; >> } >> >> /* >> @@ -3051,6 +3051,7 @@ static void put_prev_task_scx(struct rq *rq, struct task_struct *p, >> } >> } >> >> +switch_class: >> if (next && next->sched_class != &ext_sched_class) >> switch_class(rq, next); >> } >> -- >> 2.45.2 >> > > -Andrea