From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) (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 EDE5D2D780A for ; Fri, 5 Dec 2025 10:49:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.50.34 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764931803; cv=none; b=Gr3WZOo7MAWDChGUBJJCpbFE9BWUWW1+VyMWCcyR0ngY0G0OssWQbqAIploMF2kwPaTmziupWBuh6zdDMVH/UXl0gJMBwdV63PJgPgPzonAB8no5VC7lYZrncxdgDtE4M/iONPyyxLciGMv1EaK5nxbIP2FWVjiihV9bRAc/vhU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764931803; c=relaxed/simple; bh=sNgLSLQEBTTF2RcFJh7aoMAbOVRh1PEafIRPH6LxPsg=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=NviEBCp5nLK4XcuDByimOLkCC7pm3Gs/KiKHCMOpMhNtuWE7xpDUlj9CRk3SkXljlENQNSHRICuwqKYP5wQRYIow9asIW45V0v3SbRx7BBYgooB656O1fu9WlRGjbDoXJuOPM6R32WA17q9CRGpR/IjTruL20wibwYnn8kbUp/8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=SjTkT3t8; arc=none smtp.client-ip=90.155.50.34 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="SjTkT3t8" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Transfer-Encoding: Content-Type:MIME-Version:References:Message-ID:Subject:Cc:To:From:Date: Sender:Reply-To:Content-ID:Content-Description; bh=fDcwKI3q0KANDfOxaRyLtPh4GtlaBRS/jy7TXaS93QA=; b=SjTkT3t8OI/uD+okytOgmYUK4B GsgteUISq6M1aCjS7uVc28djBomZ5N4ohXeu8Iggqd+psSPwn3K5MId00X7kl9xpmhFMwCaMrMLLn DxmJwtXagfE93giOnMHPzIchjdQig8rSJK7zZjMes/Scztk8A7/a4g22JibFLx9rzStamneOvVX2m MGoRrPWz0nRj3iCRjMXxjVybZvLAHjDNqP4b228b06BhGUcPAITA5J3NgzBxWlsHGAfegFWS7Myc7 58H397NiHKHpJylB7v7syXoKN3Itaxkbrb4HpFnVBPBk8XFg0JJ2QA7k83HK1WJ0aUpI6E2+VEC4f Tv07pstw==; Received: from 2001-1c00-8d85-5700-266e-96ff-fe07-7dcc.cable.dynamic.v6.ziggo.nl ([2001:1c00:8d85:5700:266e:96ff:fe07:7dcc] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.98.2 #2 (Red Hat Linux)) id 1vRTNf-00000005aTD-3Ocq; Fri, 05 Dec 2025 10:49:43 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id DF5F430027B; Fri, 05 Dec 2025 11:49:41 +0100 (CET) Date: Fri, 5 Dec 2025 11:49:41 +0100 From: Peter Zijlstra To: Josh Don Cc: Blake Jones , Ingo Molnar , Juri Lelli , Vincent Guittot , Andrew Morton , Linus Torvalds , Madadi Vineeth Reddy , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Valentin Schneider , linux-kernel@vger.kernel.org Subject: Re: [PATCH v5] sched: reorder some fields in struct rq Message-ID: <20251205104941.GR2528459@noisy.programming.kicks-ass.net> References: <20251202023743.1524247-1-blakejones@google.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=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: On Thu, Dec 04, 2025 at 02:56:47PM -0800, Josh Don wrote: > Hi Blake, > > On Mon, Dec 1, 2025 at 6:37 PM Blake Jones wrote: > > > > This colocates some hot fields in "struct rq" to be on the same cache line > > as others that are often accessed at the same time or in similar ways. > [snip] > > Signed-off-by: Blake Jones > > Reviewed-by: Madadi Vineeth Reddy > > Tested-by: Madadi Vineeth Reddy > > Sorry, I thought I had already included a review tag when I responded > to the earlier version of this. > > Reviewed-by: Josh Don > > > --- > > kernel/sched/sched.h | 80 +++++++++++++++++++++++++++----------------- > > 1 file changed, 50 insertions(+), 30 deletions(-) > > > > v4 -> v5 changes: > > - Resynced with sched/core. > > Link to v4: https://lore.kernel.org/lkml/20251029185458.3040228-1-blakejones@google.com/T/#u > > > > v3 -> v4 changes: > > - Updated based on review comments from peterz@infradead.org: > > updated block comment in struct rq, moved "nr_iowait" to the end of the > > structure, and added "__no_randomize_layout" tag to the structure. > > Link to v3: https://lore.kernel.org/lkml/20251028080348.2177469-1-blakejones@google.com/T/#u > > > > v2 -> v3 changes: > > - Resynced and retested. Results are consistent with v2. > > Link to v2: https://lore.kernel.org/lkml/20250730205644.2595052-1-blakejones@google.com/T/#u > > > > v1 -> v2 changes: > > - Resynced to tip/sched/core tree, which has removed CONFIG_SMP. > > Link to v1: https://lore.kernel.org/lkml/20250722201339.1198239-1-blakejones@google.com/T/#u > > > > v1 was sent on July 22 of this year, over four months ago. > > The patch is straightforward and the results look compelling; > Peter/Ingo, any thoughts? I've stuck it on the pile for post -rc1 time.