From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 04AEE30C14C for ; Sun, 26 Jul 2026 12:04:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785067500; cv=none; b=m3rHfNZskXTjNCwM9IxZgQWbwjWnhwlun0ByKGwmow8c8SGzRGIXK8G+2BOWH2l9logMxMG1q24LcD4KjI9jqXANlE4PiIzy6LPjdp09pIbgOvkj3w6UTTcdekNU27f3NUMpqvmSDgCzYSzSDzy6JjfPML1ECac2DbNvVXYfHlU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785067500; c=relaxed/simple; bh=X09LtppIkxdFEe/nXafOWSTuA+b6bmQduq0/Yvh7LfU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Q1FZsv77FGlRen2XgWIqrVEAsvxuEv5D5U2QUWCtKrDj/mbLQc0sSDuhxH4sIdCVYwIPd85V6viuI6kuXyg7AyuJOgbQFoGW0flQZjUbOPNSVKTyy8j1G/CB5BoWpvulQo08quFvY8J8NRgZTgHwiyKpp1nmc2uMBebYfoHJmxE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=CKkbHMG0; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="CKkbHMG0" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2761D1F000E9; Sun, 26 Jul 2026 12:04:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1785067498; bh=uMML1efS+UPzVQLzCYqWqxIChwAo1j7w0cpTXOZDtsA=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=CKkbHMG0KXFP0DIzRLV7Y3ZGTCpddSntmKLgxKbz+wltZgFr2lioGJeY3fxGvwc9g de/3jCdJ7tbLkfVuXE7/Qok7mn7eLtNx/mU/Kcc29S2oymvlKQ2QD4zmwuxREQpoZk WvCUxNz9quGvyZO9l9ujX5xUEOq7zeHToBNo44AUI3BCx9OOPzjRvtC4NWDJw7cE2O 98dw+t4RzrcT3WbSky2FgtjdF/7l+igKl1W8dVBtRvdehkfpwIMi0/byqBPqu5o0fS YWaZz+Q+WF+VEig6eHcuCYCo36JA+NOr3O8Uf9QC9G1rg5MFkhb7BmB/MYlsU6fqWx QZ4rznoVQMzCA== From: Sasha Levin To: "stable@vger.kernel.org" Cc: Sasha Levin , Peter Zijlstra , "Janne Huttunen (Nokia)" Subject: Re: Please backport 101f3498b4bd to 6.18.y Date: Sun, 26 Jul 2026 08:04:40 -0400 Message-ID: <20260725192000.stable-0001@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: References: Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit > My attempt at a backport is below. Apologies in advance if the mail > system mangles it. The only real diff between this and the original > should be the use use of div_s64 vs div64_long + maybe tiny bit of > patch context. Thanks for putting this together, and for the weeks of production testing. I'd like to hold this one until Peter can weigh in. Upstream the revert was preceded by 4823725d9d1d ("sched/fair: Increase weight bits for avg_vruntime"), which is what actually cured the underlying rounding artifact that 6d71a9c61604 was working around. That prerequisite is part of the larger v7.1 avg_vruntime rework and isn't practical to bring back to 6.18. Reverting alone on 6.18 (which still uses the scale_load_down avg_vruntime) theoretically re-exposes that artifact, so I'd rather not queue a scheduler change like this without the author's ack. Peter, does a standalone revert of 6d71a9c61604 look correct/safe for 6.18 without 4823725d9d1d? -- Thanks, Sasha