From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7795EEB64D7 for ; Mon, 26 Jun 2023 22:59:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229750AbjFZW7K (ORCPT ); Mon, 26 Jun 2023 18:59:10 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50524 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229488AbjFZW7I (ORCPT ); Mon, 26 Jun 2023 18:59:08 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5A995199 for ; Mon, 26 Jun 2023 15:59:07 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id E224E60F79 for ; Mon, 26 Jun 2023 22:59:06 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B844FC433C0; Mon, 26 Jun 2023 22:59:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1687820346; bh=652MFVzhku0Nt68TmRIUSHH/UvVI7+/iNQrsltfUhdc=; h=Date:From:To:Subject:References:In-Reply-To:From; b=iS+ulOWO8zDjh7RgglL3o9Y6+s7N4KQtzNuxU8YWMOJyN8VGOoHS10JxAoODDSbhk /zoXeAHlFb2xgu+BSjHN6b0KWlhTmC8XWGkOWOSQ6PpbUXp26RCD4mNqCUikr1fIMu KENuFesoed8eIp25eKay0qgrOUPlH3lai+NYTB+1ONmKKJLOSiJ+pieiz3+7QBLrq7 wFSIPSWGRgYjmjxICeeqSDhn7IJ362av2u4Wzvwbnwk7tMglYjqp3u1rzEe+QmwHqM EdxQVCo06PiM49hJ2vYf0S+CaqmOFC+6K/mRir7BBm+841oDk9QN4pkM05VZCLZnpH dgSgyUuTzUqcg== Date: Tue, 27 Jun 2023 00:59:03 +0200 From: Frederic Weisbecker To: tj@kernel.org, mingo@redhat.com, peterz@infradead.org, juri.lelli@redhat.com, vincent.guittot@linaro.org, linux-kernel@vger.kernel.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, bristot@redhat.com, vschneid@redhat.com, fuyuanli@didiglobal.com, zwp10758@gmail.com, zyhtheonly@gmail.com, zyhtheonly@yeah.net Subject: Re: [PATCH v3] sched/isolation: add a workqueue parameter onto isolcpus to constrain unbound CPUs Message-ID: References: <20230622032133.GA29012@didi-ThinkCentre-M930t-N000> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230622032133.GA29012@didi-ThinkCentre-M930t-N000> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jun 22, 2023 at 11:22:17AM +0800, tiozhang wrote: > Motivation of doing this is to better improve boot times for devices when > we want to prevent our workqueue works from running on some specific CPUs, > i,e, some CPUs are busy with interrupts. > > Also remove HK_FLAG_WQ from nohz_full to prevent nohz_full overriding > workqueue's cpu config. But then nohz_full= doesn't re-affine workqueues anymore, right? > > Suggested-by: Tejun Heo > Signed-off-by: tiozhang > --- > kernel/sched/isolation.c | 10 ++++++++-- > 1 file changed, 8 insertions(+), 2 deletions(-) > > diff --git a/kernel/sched/isolation.c b/kernel/sched/isolation.c > index 373d42c707bc..5cd67c51622e 100644 > --- a/kernel/sched/isolation.c > +++ b/kernel/sched/isolation.c > @@ -181,8 +181,8 @@ static int __init housekeeping_nohz_full_setup(char *str) > { > unsigned long flags; > > - flags = HK_FLAG_TICK | HK_FLAG_WQ | HK_FLAG_TIMER | HK_FLAG_RCU | > - HK_FLAG_MISC | HK_FLAG_KTHREAD; > + flags = HK_FLAG_TICK | HK_FLAG_TIMER | HK_FLAG_RCU | HK_FLAG_MISC > + | HK_FLAG_KTHREAD; > > return housekeeping_setup(str, flags); > } > @@ -208,6 +208,12 @@ static int __init housekeeping_isolcpus_setup(char *str) > continue; > } > > + if (!strncmp(str, "workqueue,", 10)) { > + str += 10; > + flags |= HK_FLAG_WQ; > + continue; > + } > + I'm planning on removing HK_FLAG_TICK, HK_FLAG_WQ, HK_FLAG_TIMER, HK_FLAG_RCU, HK_FLAG_MISC and HK_FLAG_KTHREAD and merge them all together. Also the problem with these flags is that once they are modified on boot, you can't modify them later. I much prefer what was done in this patch: https://lore.kernel.org/all/20230623073033.GA6584@didi-ThinkCentre-M930t-N000/ Thanks! > if (!strncmp(str, "managed_irq,", 12)) { > str += 12; > flags |= HK_FLAG_MANAGED_IRQ; > -- > 2.17.1 >