From nobody Mon Feb 9 07:54:55 2026 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 533BB13CC52 for ; Wed, 27 Mar 2024 14:45:59 +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=1711550760; cv=none; b=efK6StkfzNUecVM1gkEXPOMfXUCCXKlUGZDg2+ReHV/XtRRowG+A3YcVlHTw/pHg8yz22FxMlHV4MUYRKu355QoDQASEF5wnq7FmNAUFPKkm/j2MG5vEguZ22nuQJ+xR5qwxfDVxIXAH/4NLJ2Xs0dmIbr8fTQQBn5B16lx8Nfk= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711550760; c=relaxed/simple; bh=urpLNOZKLvQ6EE4+hSYH0zcDJ4lwak85uzQzCqjptrQ=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=uHXJuk43PRGt4Cftr2s7sQ5NDuA/+zmQ6MgGYJYKkZN0qnGE6QWF2zKNaVwQVl3XazeE89aFOaWajIquh1mDKGi+qJEsJ19wUMf1wTMZpndfdrOamRqMJNnrL9l/nE+vzOnSjcBVrdBl1+U2QiT53bLlnF5psQFFIDApjxCGeoQ= 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; 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 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 1BD601595; Wed, 27 Mar 2024 07:46:33 -0700 (PDT) Received: from e125769.cambridge.arm.com (e125769.cambridge.arm.com [10.1.196.27]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 066593F64C; Wed, 27 Mar 2024 07:45:56 -0700 (PDT) From: Ryan Roberts To: Andrew Morton , David Hildenbrand , Matthew Wilcox , Huang Ying , Gao Xiang , Yu Zhao , Yang Shi , Michal Hocko , Kefeng Wang , Barry Song <21cnbao@gmail.com>, Chris Li , Lance Yang Cc: Ryan Roberts , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Barry Song Subject: [PATCH v5 5/6] mm: vmscan: Avoid split during shrink_folio_list() Date: Wed, 27 Mar 2024 14:45:36 +0000 Message-Id: <20240327144537.4165578-6-ryan.roberts@arm.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20240327144537.4165578-1-ryan.roberts@arm.com> References: <20240327144537.4165578-1-ryan.roberts@arm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Now that swap supports storing all mTHP sizes, avoid splitting large folios before swap-out. This benefits performance of the swap-out path by eliding split_folio_to_list(), which is expensive, and also sets us up for swapping in large folios in a future series. If the folio is partially mapped, we continue to split it since we want to avoid the extra IO overhead and storage of writing out pages uneccessarily. Reviewed-by: David Hildenbrand Reviewed-by: Barry Song Signed-off-by: Ryan Roberts --- mm/vmscan.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/mm/vmscan.c b/mm/vmscan.c index 00adaf1cb2c3..293120fe54f3 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -1223,11 +1223,12 @@ static unsigned int shrink_folio_list(struct list_h= ead *folio_list, if (!can_split_folio(folio, NULL)) goto activate_locked; /* - * Split folios without a PMD map right - * away. Chances are some or all of the - * tail pages can be freed without IO. + * Split partially mapped folios right + * away. We can free the unmapped pages + * without IO. */ - if (!folio_entire_mapcount(folio) && + if (data_race(!list_empty( + &folio->_deferred_list)) && split_folio_to_list(folio, folio_list)) goto activate_locked; --=20 2.25.1