From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.ilvokhin.com (mail.ilvokhin.com [178.62.254.231]) (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 BABFF19343E for ; Sat, 23 May 2026 13:50:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=178.62.254.231 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779544256; cv=none; b=hG6BPJYRkQ2Z+XIfYiC/Imcq6WtX3Kd7L0b/cVtg7QYOxO30uWLFbxiVBuvvwq1aDWsoyuN1r4cQAiTvQr7BDZJfeivM7Ucle5kgcbD9TmyQc0iR+fvaVg0h/uv61180oLrpypOyMGKF8mPSSkVSiF/BCv6yHHErgZx/hFUVc90= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779544256; c=relaxed/simple; bh=pTA+rTytqXwRZDzoAztTkydPnY88CGl7bXU/svbRiXM=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=nz+dhIyjH79w3mjSJVtZkb+Z3gSFskWfZfnAbrg9mnWZDUqn6XzS+FnsJd9mTi7M5+Ec+/MtdYuKWeCaOXJXOOs/NCOdAaUt+EmX87MarGUgl+kRY4wikZlVrtH2F9qkI3w7f9RB1zyAH1KH2gJRHEULxian0X9O30zxjdTZf9I= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=ilvokhin.com; spf=pass smtp.mailfrom=ilvokhin.com; dkim=pass (1024-bit key) header.d=ilvokhin.com header.i=@ilvokhin.com header.b=cNcsZ54F; arc=none smtp.client-ip=178.62.254.231 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=ilvokhin.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=ilvokhin.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=ilvokhin.com header.i=@ilvokhin.com header.b="cNcsZ54F" Received: from shell.ilvokhin.com (shell.ilvokhin.com [138.68.190.75]) (Authenticated sender: d@ilvokhin.com) by mail.ilvokhin.com (Postfix) with ESMTPSA id 8FE79D0A8D; Sat, 23 May 2026 13:50:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ilvokhin.com; s=mail; t=1779544246; bh=AC/2/8v0gXhGn6yBxeQK/GPYzfG5O7Mk+gnTKcGs3Js=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=cNcsZ54F2iJQFEFkHSCOO+HYLmbg8zCOX/YYa8WnJn+NxHFvmxwfVNbKnJXwkEnws 4V1ny2G1nO5rlNwTtMVCwPt0t9xDiQs6S/OaI8kZKK+pwCMmxeO9d1S1CADcKiH+fF Kt2NWMbrQYRlG95yRMdF6yCDUdjOKOws/KlJe6g0= Date: Sat, 23 May 2026 13:50:45 +0000 From: Dmitry Ilvokhin To: Andrew Morton Cc: Vlastimil Babka , Suren Baghdasaryan , Michal Hocko , Brendan Jackman , Johannes Weiner , Zi Yan , linux-mm@kvack.org, linux-kernel@vger.kernel.org, kernel-team@meta.com Subject: Re: [PATCH v2] mm/page_alloc: fix defrag_mode for non-reclaimable allocations Message-ID: References: <20260520122228.201550-1-d@ilvokhin.com> <20260521165910.e7dea6a4e591d66293d2bd47@linux-foundation.org> <20260522195426.6e764847f4c4dcbaad388291@linux-foundation.org> 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: <20260522195426.6e764847f4c4dcbaad388291@linux-foundation.org> On Fri, May 22, 2026 at 07:54:26PM -0700, Andrew Morton wrote: > On Fri, 22 May 2026 13:05:36 +0000 Dmitry Ilvokhin wrote: > > > > How serious is this to our users when running real-world workloads? > > > > We observed it on a few of the Meta workloads that adopted > > defrag_mode=1. > > > > For the service under load there were 85509 SLUB allocation failures > > messages in dmesg within 2 hours. All of them are GFP_ATOMIC allocations > > for skbuff_head_cache, despite free pages being available in other > > migratetype freelists (~13 GB free). > > For a single machine, I assume. Yes, all of that data is from a single machine. > > > Since it is networking path from the practical point of view, this means > > dropped packets, failed RPC requests, tail latency spikes and overall > > service degradation. > > OK, thanks. I assume 12 failures per second isn't a disaster, and that > there's no need to fast-track this into 7.1? Yes, I agree. No need to fast-track this.