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 6332F24395C for ; Tue, 15 Apr 2025 08:02:57 +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=1744704179; cv=none; b=CUcZR+iXJFSXH0DEroIjlyOIFyIw2CF55VhuOnZ5aZr4Z3w7vtGoAiz2zhlgFAi5jOmCGLWMjsvaZQ1oCNwc9GoAKHaWUpxelTnuLkfKSvY99a+mogVRepJgZpw/PkodJ2TOGPeHbVNf6WSiIm0g2qBoZIj8Mraoz3DFBDFb+QM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744704179; c=relaxed/simple; bh=bB9v90uUXLJMSGTtBA+KWYPBjUb8sJFHAsNnD4zAvYA=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=JOcq95iw0KVsx+kgBjaP9qTum+/BaE2k1/rUukt5olnkUZ+FXwwYI36HJzMGD/pBj66CFeisvHccbGPGb7N9ENCMwb7hZ39WnxExUmexWiJlsQjq8YaJKhcHIkdpqSeJtSjjNOqOVzrREF/T8jEg/V/FvhQlkSYRxhSGT4zvry0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (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=Oy3/b4yO; arc=none smtp.client-ip=90.155.50.34 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (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="Oy3/b4yO" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=TTmEwawP5Z2mJepsUH2z9F7/mt/Xfpdj1VKxTKYIjjs=; b=Oy3/b4yOh/s/DyIXd+tdGKvCmJ x634Z0gn+6UqI4Y+OB2GkyoPtK872FtFkufxSUVW0NTGxNCp9iL58yIKsTAlK1jvQbhuQ4byOktXT wd81lXSb3uAsjRgXyyWZGa6E9YWolj1gNCqh+XdkQ6eDYkFZORnVKpB2b/usDHhCd3v3gnNxPNR2e zSEKxEfo4xnO4qsSEINankaHE6VBMgR66pFdZdxFtZHX1cR+ZF+JzWl+Gxi6luO0OZ/nP/8XEOi1P 5uPgYKV2GY9KU+rcll2/bNVq8AYlUBhUYhWQXaRdaE0PqE2nGS1nSIMtqaYs2T2KUOT9uFf2ZT6PJ qbsWxYpw==; Received: from 77-249-17-252.cable.dynamic.v4.ziggo.nl ([77.249.17.252] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.98.2 #2 (Red Hat Linux)) id 1u4bFc-00000008EH8-24FD; Tue, 15 Apr 2025 08:02:37 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id 3D91030037D; Tue, 15 Apr 2025 10:02:35 +0200 (CEST) Date: Tue, 15 Apr 2025 10:02:35 +0200 From: Peter Zijlstra To: Rik van Riel Cc: Chris Mason , Pat Cody , mingo@redhat.com, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, vschneid@redhat.com, linux-kernel@vger.kernel.org, patcody@meta.com, kernel-team@meta.com, Breno Leitao Subject: Re: [PATCH] sched/fair: Add null pointer check to pick_next_entity() Message-ID: <20250415080235.GK5600@noisy.programming.kicks-ass.net> References: <20250320205310.779888-1-pat@patcody.io> <20250324115613.GD14944@noisy.programming.kicks-ass.net> <7B2CFC16-1ADE-4565-B555-7525A50494C2@surriel.com> <20250402082221.GT5880@noisy.programming.kicks-ass.net> 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: On Mon, Apr 14, 2025 at 03:57:42PM -0400, Rik van Riel wrote: > On Wed, 2025-04-02 at 10:22 +0200, Peter Zijlstra wrote: > > > > Please confirm what the reason for overflow is. > > > Running a large enough sample size has its benefits. > > We have hit 3 out of the 4 warnings below. > > The only one we did not hit is the cfs_rq->avg_load != avg_load > warning. Fair enough, that one really isn't hard. > Most of the time we seem to hit the warnings from the > code that removes tasks from the runqueue, *blink*.. > but we are > occasionally seeing it when adding tasks to the runqueue, > as well. OK, let me try and get my head around that.