From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (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 7D4EB343203 for ; Mon, 15 Sep 2025 14:49:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757947791; cv=none; b=hfNDoCLOHHLIMDpOK6IbTseDrzUMtaWBaOwyVILLICUqqsoJC8JUnMYeAu6ob1X6jzMTGOengSf7iwqW1U4RfCIO4lLUTo49+vJGKFEYLnDT3n3ceT8ZPvS9pRVD+RUDgAOy/MNqNTacBQhQEgjV5dSlZlZb7TJwM1jKMJWl8Rg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757947791; c=relaxed/simple; bh=EQrR3as8r6JttpBYEwX3XQQTxMYtTk/VHuoMMD/Weqc=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=BJ9INlt0S/VvscHkOV4lt/KVNlsizQv6qIkZzL/oysmafWPE2zjKtKoOb8bgGvKDGEhFUucXtDK7lQL/sUyA0ggr3XlQ+XR4XPA66OkJRej9U4MrsMipyAq9gZiABkdU+ndlPUeabygdmHyvNWsOXVf7D7bN2jFZAYIgRJgk92k= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=iRlVEryl; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="iRlVEryl" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1757947788; 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=CkA/y861UY0j0NSM/jI1mVaVre4MXQ6jr6/SWw+imII=; b=iRlVErylVtwlecChbxbD23zb5qs1aRyrVrnExiMJ57VWMsWf+zWzOBYDSa6cRbJ80voGSK Y+/9hcymO+1EvbQxs46lm4B6BVZ2RTjWSJ+L9S09TG49Pp+H2Z6wQ23ItL7D/C5IU02qjd NLxjPn1kOrcdZnqEsZpuw/2GGZgjHro= Received: from mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-397-oP7DMVCmMkaCpixDQ5C5Vg-1; Mon, 15 Sep 2025 10:49:44 -0400 X-MC-Unique: oP7DMVCmMkaCpixDQ5C5Vg-1 X-Mimecast-MFC-AGG-ID: oP7DMVCmMkaCpixDQ5C5Vg_1757947782 Received: from mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.111]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id B6BF81800447; Mon, 15 Sep 2025 14:49:41 +0000 (UTC) Received: from localhost (unknown [10.22.88.26]) by mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 19A651800451; Mon, 15 Sep 2025 14:49:39 +0000 (UTC) Date: Mon, 15 Sep 2025 11:49:37 -0300 From: "Luis Claudio R. Goncalves" To: Sebastian Andrzej Siewior Cc: Peter Zijlstra , Oleg Nesterov , Clark Williams , Steven Rostedt , Tejun Heo , David Vernet , Barret Rhoden , Josh Don , Crystal Wood , linux-kernel@vger.kernel.org, linux-rt-devel@lists.linux.dev, Juri Lelli , Ben Segall , Dietmar Eggemann , Ingo Molnar , Mel Gorman , Valentin Schneider , Vincent Guittot , Thomas Gleixner , Wander Lairson Costa Subject: Re: [RESEND PATCH] sched: restore the behavior of put_task_struct() for non-rt Message-ID: References: <20250915113812.GB3245006@noisy.programming.kicks-ass.net> <20250915122444.Gg_Tsymz@linutronix.de> 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: <20250915122444.Gg_Tsymz@linutronix.de> X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.111 On Mon, Sep 15, 2025 at 02:24:44PM +0200, Sebastian Andrzej Siewior wrote: > On 2025-09-15 13:38:12 [+0200], Peter Zijlstra wrote: > > Right, but I thought we did want to make this behaviour consistent. > > That is correct, that is what I asked for (either consistent or a > compelling reason why not). I received a ping from colleagues investigating a problem possible caused by excessive pressure on RCU and this change could make the problem worse. But last I heard from them, sounds like the problem they are investigating lies elsewhere. That said, I don't have problems either way, limiting the change to RT or keeping it general. I will follow whatever guidance I get from you all. Luis > Oleg pointed out that the patch description does not match the change. > That is the only complaint. > > > And IIRC RT has been running with this for ages, and never seen a > > problem. > > The syz-bot picked up RT recently. Other than that, yes, RT had it for > ages. > > Sebastian > ---end quoted text---