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 2F5C62AF15 for ; Tue, 10 Sep 2024 10:50:00 +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=1725965401; cv=none; b=BXLn2k9wqRsNHUhJdoM3xIhgqBK3Vh7L5iXc/nRNNlcN9QzaLuboamHm3vlD1Pwl8vHbblC4/GGkQXAJkN1Nu7HSAX1tyTcHSWPDmLGBJn6xQqV7E10zut/NQ7+d+756V+7sisZNTZvw6uAKo/wNLXE0594nNB6JEN9DbR/kUls= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725965401; c=relaxed/simple; bh=tjRIYlNK9oEPZidwMLKbN36DkLeUA/Mt/bor3mAYdzg=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=YGHq7WMk8BlseHeVN4vWVmCfFCqSglQOLtPflbtAyFAXTeHjymLb12IuEStXtaFhq4Z7cUUnWdfMjznRCyBW1O//bKqCCITRLHbTpSvYNDxw1lMAEQCrqtsf217pct7ySXxemhkY4Lv1s2HbkkUmpKFl+FtzVavzuVME532xfkk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none 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=GihFLLgL; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none 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="GihFLLgL" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1725965399; 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=YZgcuspLqcfqCSPDpXA3njSxo7eX4xp8bIeZdoi4VBY=; b=GihFLLgLcHSM3x32PUoe18B0ek8V/o3TIQahuqRQoCeW3u/DfsVxB9p/B4MW6i16OAQTNI O6DqoJo/T9xmmJ8KFV3vxjCe3y/AzmZ1XAxLORXOCjImvkKJM0M5FKFAktb0EEgkR/aIkR 4TI6Pn/2c1wzeFGdZAcN6usdCGymodc= Received: from mx-prod-mc-01.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-199-iGTAO14eOdC-kAtyuE9GqQ-1; Tue, 10 Sep 2024 06:49:55 -0400 X-MC-Unique: iGTAO14eOdC-kAtyuE9GqQ-1 Received: from mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.12]) (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-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 08EAE19560B2; Tue, 10 Sep 2024 10:49:54 +0000 (UTC) Received: from pauld.westford.csb (unknown [10.22.32.72]) by mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 009A219560AA; Tue, 10 Sep 2024 10:49:51 +0000 (UTC) Date: Tue, 10 Sep 2024 06:49:49 -0400 From: Phil Auld To: Liu Song Cc: tj@kernel.org, lizefan.x@bytedance.com, hannes@cmpxchg.org, mkoutny@suse.com, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [RFC PATCH] sched, cgroup: cgroup1 can also take the non-RUNTIME_INF min Message-ID: <20240910104949.GA318990@pauld.westford.csb> References: <20240910074832.62536-1-liusong@linux.alibaba.com> Precedence: bulk X-Mailing-List: cgroups@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: <20240910074832.62536-1-liusong@linux.alibaba.com> X-Scanned-By: MIMEDefang 3.0 on 10.30.177.12 Hi, On Tue, Sep 10, 2024 at 03:48:32PM +0800 Liu Song wrote: > For the handling logic of child_quota, there is no need to distinguish > between cgroup1 and cgroup2, so unify the handling logic here. > > Signed-off-by: Liu Song > --- > kernel/sched/core.c | 21 +++++---------------- > 1 file changed, 5 insertions(+), 16 deletions(-) > > diff --git a/kernel/sched/core.c b/kernel/sched/core.c > index e752146e59a4..8418c67faa69 100644 > --- a/kernel/sched/core.c > +++ b/kernel/sched/core.c > @@ -9501,23 +9501,12 @@ static int tg_cfs_schedulable_down(struct task_group *tg, void *data) > parent_quota = parent_b->hierarchical_quota; > > /* > - * Ensure max(child_quota) <= parent_quota. On cgroup2, > - * always take the non-RUNTIME_INF min. On cgroup1, only > - * inherit when no limit is set. In both cases this is used > - * by the scheduler to determine if a given CFS task has a > - * bandwidth constraint at some higher level. This comment is here for a reason. Please don't remove it. > + * Ensure max(child_quota) <= parent_quota. > */ > - if (cgroup_subsys_on_dfl(cpu_cgrp_subsys)) { > - if (quota == RUNTIME_INF) > - quota = parent_quota; > - else if (parent_quota != RUNTIME_INF) > - quota = min(quota, parent_quota); > - } else { > - if (quota == RUNTIME_INF) > - quota = parent_quota; > - else if (parent_quota != RUNTIME_INF && quota > parent_quota) > - return -EINVAL; > - } > + if (quota == RUNTIME_INF) > + quota = parent_quota; > + else if (parent_quota != RUNTIME_INF) > + quota = min(quota, parent_quota); > } > cfs_b->hierarchical_quota = quota; > I don't think there is a need to optimize this slow path to allow setting invalid values which have to be handled in fast paths. And this will change expected behavior. So NAK. Cheers, Phil --