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 8D9D5ECAAD4 for ; Mon, 29 Aug 2022 12:50:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229459AbiH2MuW (ORCPT ); Mon, 29 Aug 2022 08:50:22 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40182 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230140AbiH2MuD (ORCPT ); Mon, 29 Aug 2022 08:50:03 -0400 Received: from outbound-smtp18.blacknight.com (outbound-smtp18.blacknight.com [46.22.139.245]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 35622861CB for ; Mon, 29 Aug 2022 05:36:17 -0700 (PDT) Received: from mail.blacknight.com (pemlinmail02.blacknight.ie [81.17.254.11]) by outbound-smtp18.blacknight.com (Postfix) with ESMTPS id 4E44C1C3A74 for ; Mon, 29 Aug 2022 13:36:16 +0100 (IST) Received: (qmail 8212 invoked from network); 29 Aug 2022 12:36:16 -0000 Received: from unknown (HELO techsingularity.net) (mgorman@techsingularity.net@[84.203.198.246]) by 81.17.254.9 with ESMTPSA (AES256-SHA encrypted, authenticated); 29 Aug 2022 12:36:16 -0000 Date: Mon, 29 Aug 2022 13:36:10 +0100 From: Mel Gorman To: Abel Wu Cc: Peter Zijlstra , Mel Gorman , Vincent Guittot , Josh Don , Chen Yu , linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/5] sched/fair: default to false in test_idle_cores Message-ID: <20220829123610.iooaxujglh2l43x6@techsingularity.net> References: <20220712082036.5130-1-wuyun.abel@bytedance.com> <20220712082036.5130-3-wuyun.abel@bytedance.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <20220712082036.5130-3-wuyun.abel@bytedance.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jul 12, 2022 at 04:20:33PM +0800, Abel Wu wrote: > It's uncertain whether idle cores exist or not if shared sched- > domains are not ready, so returning "no idle cores" usually > makes sense. > > While __update_idle_core() is an exception, it checks status > of this core and set to shared sched-domain if necessary. So > the whole logic depends on the existence of sds, and can bail > out early if !sds. > > It's somehow a little tricky, and as Josh suggested that it > should be transient while the domain isn't ready. So remove > the self-defined default value to make things more clearer, > while introduce little overhead in idle path. > > Signed-off-by: Abel Wu > Reviewed-by: Josh Don Acked-by: Mel Gorman -- Mel Gorman SUSE Labs