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 C8AA42DF128; Tue, 2 Jun 2026 17:33:36 +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=1780421617; cv=none; b=cQL54jeXTKMQ9HwNdAxQACIUptO0OfPQMxRGd8H5zu9wMwbAJjKwxVnSKQTxh0hc7flOTjST2ADnb83SWACm5RhYjoil7NLaW+bnX6rSpxkTXwQIue8dhuomfS8QkQRpPI5qgGMFAIH4AeAO3qKu5wOA0uk2qNGXZ4d9tDjrlVs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780421617; c=relaxed/simple; bh=UzZDW0C+Xie61rTyRkfKLrlsLlC51bTjswEfoyaJRhQ=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=LnsSPM+R9FgDOC7UVbBETe16A1pJHlS9/077nGOBFNgIkcfQm2RCKW5cDTBwRytrV6LHT4a5jJXcLKXDOqkiSoL46LoMMSMmFUmlAEbegftaO/W2SePxf5zHE8uSWhCzHyry96weNclGuFnv2jCtl07QsVWQxdRGShtLexiq6uE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=a0eGlr8c; 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="a0eGlr8c" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 420AC1F00898; Tue, 2 Jun 2026 17:33:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1780421616; bh=o5KkLRZDKHzqzgauZa36DRNu943jxeoDnNjfgu5c58g=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=a0eGlr8cNqe5fWtVVRIkjgBEI8yknJFz5yl76rkX84Jt7Tzwx3d/Y2U8C43dPL0CS 1Y8HN2p36jLfxyiOxKF3kVZl9kM96B2bWRfwDb9y3OeetGo13hNso5NA2FVQBbadm7 VkhxzruT9bWIuKBbaV0AaFOqTnhdKh2t7Oyy6f4VC6tYFoSAP3hvUP45dm6i6KU10c ZTEt90pVa7twql29hgu3gqBLoFyoII+8UJWWPik+/hajQp+ouvJSwudD+ZcniEpZQQ mVkS8wf7NHJv8Kii8vWaKnWOZiCbeHRmo1yKOmuC6DPXOy9Fe+GmlFsZcuibmebhyG 5r624HcOZmBkA== Message-ID: <2f30e6da-0b1c-41e6-a74f-893d4ba67f65@kernel.org> Date: Tue, 2 Jun 2026 19:33:28 +0200 Precedence: bulk X-Mailing-List: cgroups@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 1/1] mm/thp: clear deferred split shrinker bits when queues drain To: Lance Yang , akpm@linux-foundation.org, hannes@cmpxchg.org Cc: ljs@kernel.org, shakeel.butt@linux.dev, mhocko@kernel.org, david@fromorbit.com, roman.gushchin@linux.dev, muchun.song@linux.dev, qi.zheng@linux.dev, yosry.ahmed@linux.dev, ziy@nvidia.com, liam@infradead.org, usama.arif@linux.dev, kas@kernel.org, vbabka@kernel.org, ryncsn@gmail.com, zaslonko@linux.ibm.com, gor@linux.ibm.com, wangkefeng.wang@huawei.com, baolin.wang@linux.alibaba.com, baohua@kernel.org, dev.jain@arm.com, npache@redhat.com, ryan.roberts@arm.com, cgroups@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20260602043453.67597-1-lance.yang@linux.dev> <1dce1561-b42a-4322-a99f-89eba1e7c227@linux.dev> <716c7351-2641-4317-8675-e07a16a1efe2@kernel.org> <63797977-1c18-4885-8099-f5c21c80da39@linux.dev> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit On 6/2/26 14:47, Lance Yang wrote: > > > On 2026/6/2 20:11, David Hildenbrand (Arm) wrote: >> On 6/2/26 06:38, Lance Yang wrote: >>> Sorry, I missed Johannes in Cc ... >>> >> >> What's the effect of that? Would we consider it a fix that we'd want to backport? > > Just a stale memcg shrinker bit :) I'd treat this patch as a small > cleanup. > > Once the queue is empty, count_objects() returns 0. That skips the scan, > but shrink_slab_memcg() only clears the bit on SHRINK_EMPTY, not 0. > > So memcg reclaim can keep calling the shrinker even though there is > nothing on that queue. > >>> >> >> This is against Johannes' work, right? > > Yep, I noticed it there, but the behavior is older. > >> If this is a fix, likely it would be fixing 87eaceb3faa5 ("mm: thp: make >> deferred split shrinker memcg aware"), right? > > No missed reclaim, just some extra reclaim work :) Thanks for clarifying! :) Reviewed-by: David Hildenbrand (Arm) -- Cheers, David