From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 342972D052 for ; Sun, 13 Apr 2025 15:05:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=193.142.43.55 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744556756; cv=none; b=i36/s9VPgarG2ew6W0MPGSEOTjkgZ0Tvzqbvm+d63S7KvxC9YOfdBDyFVBhHbex2T7DpQEeAPXrrqdDzN4VPgKWlsH8g9PNk91oIVq38CvtHXb4j4SAig2FTwLJHTJfhjY6esNnoSAM+zqTL36sGkzxXD7/QdcoZe7afvsVhglU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744556756; c=relaxed/simple; bh=wh+2AVUkXsj1x0AjpoRQ/T9Fm+RZCQ1mI0V9pIyWM30=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=QXfb+sjTMGWFXwP0ZNRjbjF4B/hn7ZL3Az0PaUaYmKqhXEZomo2PuQi50X+xbfISfsUillAXoJje9KUwoQ7WFKX+6eiUrrTJ/8qqbmIwZQg9IV+TaWyNVkb61K3/Tzs/RHZR+RZvgRUx27FLm1S3gi8JQP/C1XCwUVl0s2xzNhI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de; spf=pass smtp.mailfrom=linutronix.de; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=V8uDCgty; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=oY0wF5gd; arc=none smtp.client-ip=193.142.43.55 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linutronix.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="V8uDCgty"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="oY0wF5gd" Date: Sun, 13 Apr 2025 17:05:40 +0200 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1744556746; 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: in-reply-to:in-reply-to:references:references; bh=jv50ZCVz1GnW72SCCXXhpMw7sdaqRH3PIBwsNn5sMQ4=; b=V8uDCgty1q9ap2LN46+1Umc72knzzRD0JP4mhEZczaRXXBdoHwtn5cAeYKr5zTp1icDlQV t1/KegE4mGDg3LkNwHJ+lXPpCD8zkxDPK0cPerLh/TvmYWL8lCndvYUPbVYcO0irz76KVp KwL+BvvJYw7RIUwp1m4SLTHKSLR3G7/PxnL+GspcSQeZ0gWiKGU1qTkJSuB9jQavmZkwa4 ChSeb4/lNvzJyrjV16AwHe22uf4ZzSq528wieslGk6lZuVikGxrULUYoSxYuZvoPyf4Ih1 yz0dpvrGKCumQaZCvEcFcNyYwDvNf3r4opZe9vOoC5v9dlQo7aMw+S8IHHVrFQ== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1744556746; 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: in-reply-to:in-reply-to:references:references; bh=jv50ZCVz1GnW72SCCXXhpMw7sdaqRH3PIBwsNn5sMQ4=; b=oY0wF5gdE1JMtd59uTpXNB2Pm1FshTBDRla4ZOpXHwd2qeYQtTMJfrxur1+xuJrB99HEGK XEaQhDuRL5+wBtBg== From: Nam Cao To: Gabriele Monaco Cc: linux-kernel@vger.kernel.org, Ingo Molnar , Peter Zijlstra , Tomas Glozar , Juri Lelli Subject: Re: [RFC PATCH 6/9] sched: Treat try_to_block_task with pending signal as wakeup Message-ID: <20250413150540.3ZW7XJVs@linutronix.de> References: <20250404084512.98552-11-gmonaco@redhat.com> <20250404084512.98552-17-gmonaco@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250404084512.98552-17-gmonaco@redhat.com> On Fri, Apr 04, 2025 at 10:45:19AM +0200, Gabriele Monaco wrote: > If a task sets itself to interruptible and schedules, the __schedule > function checks whether there's a pending signal and, if that's the > case, updates the state of the task to runnable instead of dequeuing. > By looking at the tracepoints, we see the task enters the scheduler > while sleepable but exits as runnable. From a modelling perspective, > this is equivalent to a wakeup and the tracepoints should reflect that. > > Add the waking/wakeup tracepoints in the try_to_block_task function and > set the prev_state used by the sched_switch tracepoint to TASK_RUNNING > if the task had a pending signal and was not blocked. > > Signed-off-by: Gabriele Monaco > --- > kernel/sched/core.c | 11 +++++++++-- > 1 file changed, 9 insertions(+), 2 deletions(-) > > diff --git a/kernel/sched/core.c b/kernel/sched/core.c > index f2f79236d5811..48cb32abce01a 100644 > --- a/kernel/sched/core.c > +++ b/kernel/sched/core.c > @@ -6584,7 +6584,12 @@ static bool try_to_block_task(struct rq *rq, struct task_struct *p, > int flags = DEQUEUE_NOCLOCK; > > if (signal_pending_state(task_state, p)) { > - WRITE_ONCE(p->__state, TASK_RUNNING); > + /* > + * From a modelling perspective, this is equivalent to a wakeup > + * before dequeuing the task: trace accordingly. > + */ > + trace_sched_waking(p); > + ttwu_do_wakeup(p); I don't think we should put trace_sched_waking() here. trace_sched_waking() "is guaranteed to be called from the waking context", and this is not the waking context. There is already a trace_sched_waking() in signal_wake_up_state(). This is duplicating that, in the wrong context. ttwu_do_wakeup() alone should be sufficient? Best regards, Nam