From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 6D0A03A7F4C; Fri, 20 Mar 2026 11:41:07 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774006867; cv=none; b=cyIphF91RYHo7Dqa//ZL7G3U/zq3XinERI5OrqXlZqRJEcZSetebgsucbDXqrotl1bruUKJ4+ImdfQsOeO29CvobiAVFEpWO5b1dt+lFxJv1FrXTw9fTADy23Hwr7N28eX8QrEq8m1SRhfYbljm52g87Z8ot6J2WHAkBkeeFL5s= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774006867; c=relaxed/simple; bh=ZP22FKPvmoZEN2zvYQzJ4Q95BDfg0EI3zNhotznuaMM=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=tjPR3zIySfZWqK9v/I/7hXy4KnStZ94LERbq6wfC+K4N/DFFgFB8VtEjHK231eM4nVEfOCNECiye5yc+HOT7EE5aPujGrIxHtk/bQOlkbY85EunOPGubdZsCvkVtiTz9JxrxH/Jj36OwZYSsEUCNtbJIMUWCgCy/y6PCAPXtLik= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=BbSL0S09; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="BbSL0S09" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9F853C4CEF7; Fri, 20 Mar 2026 11:41:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1774006867; bh=ZP22FKPvmoZEN2zvYQzJ4Q95BDfg0EI3zNhotznuaMM=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=BbSL0S09gbjTOCH902eTaZWwFJxiLeFTOOB0ffYmk4eaCstJylLTx1t5vmQfw3sMW FBMRq8KlvWpL9RknySCg/Y492McoR4jYgskaAyrGVYHIrcZ4eeFSNn0aQ8ypCGvgjG lfg23tUFLhNdRJPXoTIUvDcwRh7KGTg/AsFBUXhM5zjomrWRfW4QWxwHpitwcXKeIA jb4nm4inocCahiqGBS1wWaxnbzyMsjezBAX9clB6/D/XBeTHLT05CRFBfMgFru8tTx WJiNRL4QO4VaqozpqEW6+ho4h+ACObKTjF3olxl/LyBzntH1TbNdMMD7mNhDBvQ6Fz 8YUWugdygI+SA== Message-ID: Date: Fri, 20 Mar 2026 12:41:00 +0100 Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3] mm: migrate: requeue destination folio on deferred split queue To: Andrew Morton , SeongJae Park Cc: Usama Arif , npache@redhat.com, ziy@nvidia.com, willy@infradead.org, linux-mm@kvack.org, matthew.brost@intel.com, joshua.hahnjy@gmail.com, hannes@cmpxchg.org, rakie.kim@sk.com, byungchul@sk.com, gourry@gourry.net, ying.huang@linux.alibaba.com, apopple@nvidia.com, linux-kernel@vger.kernel.org, kernel-team@meta.com, richard.weiyang@gmail.com, stable@vger.kernel.org References: <20260314154042.327ba957b1a8c10f64ae0169@linux-foundation.org> <20260315000555.76876-1-sj@kernel.org> <20260314172321.3ca062bb70e51fefa633a6fe@linux-foundation.org> 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 3/15/26 01:23, Andrew Morton wrote: > On Sat, 14 Mar 2026 17:05:54 -0700 SeongJae Park wrote: > >> Because THPs are >> removed from the deferred_list, THP shinker cannot split the underutilized THPs >> in time. As a result, users will show less free memory than before. > > That'll do, thanks ;) > > Pasted, added cc:stable. It's been there since 6.12 so I don't see a > need to rush this in, so I won't move this into mm-hotfixes - it'll go > into mainline for 7.1-rc1 after which -stable should pick it up. Makes sense. I guess using the partially-mapped is only a slight problem, because we usually try to split partially-mapped before migrating. So it's mostly about over-allocated THPs (mostly 0) not getting scanned and split+reclaimed after they were migrated. Under memory pressure without swap, that might create a user-visible problem, especially when many such THPs are migrated before being scanned for zeropages that can be reclaimed. -- Cheers, David