From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 57CC345D5F3; Mon, 19 Oct 2026 06:58:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792393132; cv=none; b=VWPhLvC6TvPP2FHFYaYz1STTIkNuQ8lq0f49BTDQ3rxIOyqk3f8FcTZ9e+kBtehhwWh9kpwJUMbzGlLAtJYoNLjRJww1UZSBOmm94EFILY9Kp/Rv2+82zRG0bOtjOqErWr+vx9kJ5ZiYFRR4q/w7kwj1ih9NSwtG9erIOfYevEU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792393132; c=relaxed/simple; bh=jKcRI0F9aHnlKD651grREaBBW4xvRcUMzBlgAiHKlsU=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=jNoSbcnDSqx9p0XaDDnR0Ma+kki1ccqM6vWlqmvE6RChURg462fokF9RBzzuSq1B3YHOgpb2HUIkMBcmasEMCxQEAFw1Bw/hC3zKOghNnnM68I5PcaOjkFqaMnpn6PWCHkHnUTgSoqdJu933oolU8Qb5urwb6/6xL8/X+3TkBYE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b=StlLDKq4; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b="StlLDKq4" Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 3F4841477; Sun, 18 Oct 2026 23:58:46 -0700 (PDT) Received: from [10.164.148.56] (MacBook-Pro-3.blr.arm.com [10.164.148.56]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 514DC3F673; Sun, 18 Oct 2026 23:58:44 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1792393129; bh=jKcRI0F9aHnlKD651grREaBBW4xvRcUMzBlgAiHKlsU=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=StlLDKq4P1yblYmcNUL/S2ln1AqLeYYRPcJPR+/GUUMAOs1w3CfSJYbdyEfSHULs+ yNXPO49brP9+UjPFeg1bY6f39wNxEV9GIf+ejuiDxy5qXrhRH/cH9ROgchLpwdaLtX AYklqgynUtNpXJDDuA7feuEpCmp7LhrGsihDk9Ms= Message-ID: <4aa14b41-9b89-494c-8825-55fffd5a541c@arm.com> Date: Mon, 19 Oct 2026 12:28:40 +0530 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3] mm: page_alloc: make defrag_mode retries follow the promoted order To: Kiryl Shutsemau , "Vlastimil Babka (SUSE)" Cc: Johannes Weiner , Andrew Morton , David Hildenbrand , Harry Yoo , Usama Arif , Suren Baghdasaryan , Michal Hocko , Brendan Jackman , Zi Yan , Shakeel Butt , linux-mm@kvack.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@meta.com References: <20261009125503.126202-1-kas@kernel.org> <15a9e03e-c748-4e51-b8cc-583a3610c897@kernel.org> <20261012192834.6934ef85444dee4a60d6d876@linux-foundation.org> <20261014202936.GC371161@cmpxchg.org> <78238103-3a7f-432c-b1df-bd14d7cf4bb1@kernel.org> Content-Language: en-US From: Dev Jain In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 15/10/26 6:25 pm, Kiryl Shutsemau wrote: > On Thu, Oct 15, 2026 at 09:16:36AM +0200, Vlastimil Babka (SUSE) wrote: >>> And agree 7.4-rc1 with CC stable is fine. Sadly, not sure if anyone >>> but Meta is using the feature right now. >> >> I thought it was there for a long time but it was only added in 2025 :) At >> least the enterprise world is slow to adopt things, AFAICS. > > I was thinking to propose a patch after merge window to make defrag_mode > default. Do you think it is too early? I don't think it is ever going > to be truly stabilized without wider exposure. AFAIU defrag mode is not going to improve mTHP allocation success. I ran a synthetic benchmark faulting in lots of 64k mTHP with swap enabled, defrag mode caused me to enter a warn_alloc (and 8 times more compact_stalls), which didn't happen without defrag. So perhaps bundle the default with pageblock_order eagerness etc. > > We also discussed with Johannes to make a stricter (defrag_mode=2?) mode > that will not give up on fragmentation ever, but OOM instead. >