From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 56805105F796 for ; Fri, 13 Mar 2026 10:40:42 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 599D96B0005; Fri, 13 Mar 2026 06:40:41 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 530496B0088; Fri, 13 Mar 2026 06:40:41 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 466666B0089; Fri, 13 Mar 2026 06:40:41 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id 33C866B0005 for ; Fri, 13 Mar 2026 06:40:41 -0400 (EDT) Received: from smtpin24.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay05.hostedemail.com (Postfix) with ESMTP id 2A7B25B900 for ; Fri, 13 Mar 2026 10:40:40 +0000 (UTC) X-FDA: 84540696240.24.22E0066 Received: from out-178.mta0.migadu.com (out-178.mta0.migadu.com [91.218.175.178]) by imf14.hostedemail.com (Postfix) with ESMTP id 3951A100005 for ; Fri, 13 Mar 2026 10:40:37 +0000 (UTC) Authentication-Results: imf14.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b="jORxnQ/C"; dmarc=pass (policy=none) header.from=linux.dev; spf=pass (imf14.hostedemail.com: domain of usama.arif@linux.dev designates 91.218.175.178 as permitted sender) smtp.mailfrom=usama.arif@linux.dev ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1773398438; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=3bRz0a5rDf3B7IZQUMIebticNEhlGjLTFEMcGXq89IU=; b=qpaCfzStzYgMW3MEaGu3rjaHEtdF6sIEof+T5fnDeyIEFOzKx+XTFdM19lD3AidqXr+MBN LKfNiOL9PvE5tQ4VrD9z/HF5EsvmfZrmS7xB9bHDD8DlEo47xLM7byu+arM5VCuJ7Rs5tF dJpA/H8eK550yGg9ZUYiYMw5d/AWI+0= ARC-Authentication-Results: i=1; imf14.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b="jORxnQ/C"; dmarc=pass (policy=none) header.from=linux.dev; spf=pass (imf14.hostedemail.com: domain of usama.arif@linux.dev designates 91.218.175.178 as permitted sender) smtp.mailfrom=usama.arif@linux.dev ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1773398438; a=rsa-sha256; cv=none; b=peSdXo+ycWtU1J8zfbO8Bl5rL+Jpt18UfFJFnUu+F2VCKaSH23DEZdJPbJQp+lnSqZF/Sc gE5B6GaTvmqvGKY0EpGc/hMIWt1UM5HcoSytUUN8FmTR4B2eauUUY2z45m8r5P2G2HxrT7 iKpno2t0/5Xe/hd5mlYY2HGAEIXBD5c= Message-ID: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1773398435; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=3bRz0a5rDf3B7IZQUMIebticNEhlGjLTFEMcGXq89IU=; b=jORxnQ/CClGmZiyZq5YW/ui3uCz8vIxhsfkcXEcQkLuaZqufBN9zXYt+nV5DXaBTlThPnN O6vuRlNHol4OE/ixrrJ0fAFgtvrTmXUcL5JngaiSvjRnCV7XdPLs2LbV6iMu7vNhpvYawx fqBAxtD6NBt934ZI4NcyFvqw7yG7gRU= Date: Fri, 13 Mar 2026 13:40:29 +0300 MIME-Version: 1.0 Subject: Re: [PATCH v3] mm: migrate: requeue destination folio on deferred split queue Content-Language: en-GB To: Andrew Morton , SeongJae Park Cc: npache@redhat.com, david@kernel.org, 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: <20260312104723.1351321-1-usama.arif@linux.dev> <20260313001630.80081-1-sj@kernel.org> <20260312175241.01b876f3b325264f43312d79@linux-foundation.org> X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Usama Arif In-Reply-To: <20260312175241.01b876f3b325264f43312d79@linux-foundation.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Migadu-Flow: FLOW_OUT X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 3951A100005 X-Stat-Signature: naiz3i71cw9wgphodsnc11od1nbmjxg5 X-Rspam-User: X-HE-Tag: 1773398437-43793 X-HE-Meta: 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 ctw9Gy6a DgjTt7itaBZgNJtgHZk4z6aGQ6GpW41TVdNd3x97oa+GFNLm3X+yasj9Oms3pRSJN3tO+Hi0G3824qnE5BQeWlaUBzDijXwqk3kAsNzYiA5pgO1nTbzynguRpfPo0vFaQ8xPhSOTRNNp4FSG0No6+5+pK2T67ICNPmRUQvqqr5tAF752S14kLepwg330TrYbwgv7yM3+cSm+gqEtZqmrLL7ep4hsbXM4GTCXPRWckiYwW5E3wc+ST0WvuIjZyQBNlyO2BKkYSwWGvszvFKDPPNeLy581ihgLIic7JFmLEqzz3TS6HuXbRzm58xWZSDEIWSPRyYsKHRfrIN2ZUSt01FzngVzRdOt2QbrmSXIVeS/10rE0= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 13/03/2026 03:52, Andrew Morton wrote: > On Thu, 12 Mar 2026 17:16:30 -0700 SeongJae Park wrote: > >>> By the time migrate_folio_move() runs, partially mapped folios without a >>> pin have already been split by migrate_pages_batch(). So only two cases >>> remain on the deferred list at this point: >>> 1. Partially mapped folios with a pin (split failed). >>> 2. Fully mapped but potentially underused folios. >>> The recorded partially_mapped state is forwarded to deferred_split_folio() >>> so that the destination folio is correctly re-queued in both cases. >>> >>> Reported-by: Johannes Weiner >>> Fixes: dafff3f4c850 ("mm: split underused THPs") >> >> Seems the commit is merged in 6.12. And I assume the user impact on >> THP-shrinker enabled systems is visible. If so, should we Cc stable@ ? > > I think the user impact should be visible to backport, but the > changelog is elusive on details? > The original patches added THPs to deferred_list at fault/collapse, they got removed but not added back to the list after migration. This patch adds them to the deferred_list on migration. The user would not expect the THPs to get removed from deferred_list on migration, so this fixes user expectations. I have CC-ed stable@vger.kernel.org to this email. Should I resend the patch with CC stable in commit message?