From nobody Mon Feb 9 04:14:35 2026 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 44D6145C0B for ; Mon, 11 Mar 2024 15:01:22 +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=1710169283; cv=none; b=RoFGck0VVU05NhlSqbptikJPED17lrffY74r/ArLuMYi5gGyk0eeE6J1sXaRckbRZs7hGLXbjpx0IHIjkwwQJzogh30Pa57gPlBd/UhO+x4rA6wi4ZPt3OWdcjOU2F4mhgAxzLjQ+wj5hV0IerQAgJuNrHubFPrFJozuDOjdHTg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1710169283; c=relaxed/simple; bh=r3szxxcJy6Mog/D+s2eYuesLonZdIzg75Pwy4/lQ7bk=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=g2mOBDVHPR6klL+RwT0J8p96RNTBKr+b9ZvOntTw4WmBXqIjumTiCwwIOEzAoKh8kMVcvqKHemVBiVJzR9sz6UAfcLl+9Tbxw2eCS/aa9wM+EYd+g/FLFx/Zf0RFJLc1nzpD9zG+8yH0GrtlNxdfGeuJdCcueoDj8H68tOOeB48= 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 B4CFEFEC; Mon, 11 Mar 2024 08:01:58 -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 CCDCB3F64C; Mon, 11 Mar 2024 08:01:19 -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 Cc: Ryan Roberts , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [PATCH v4 5/6] mm: vmscan: Avoid split during shrink_folio_list() Date: Mon, 11 Mar 2024 15:00:57 +0000 Message-Id: <20240311150058.1122862-6-ryan.roberts@arm.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20240311150058.1122862-1-ryan.roberts@arm.com> References: <20240311150058.1122862-1-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. Signed-off-by: Ryan Roberts Reviewed-by: Barry Song Reviewed-by: David Hildenbrand --- mm/vmscan.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/mm/vmscan.c b/mm/vmscan.c index cf7d4cf47f1a..0ebec99e04c6 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -1222,11 +1222,12 @@ 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 map + * right away. Chances are some or all + * of the tail pages can be freed + * without IO. */ - if (!folio_entire_mapcount(folio) && + if (!list_empty(&folio->_deferred_list) && split_folio_to_list(folio, folio_list)) goto activate_locked; --=20 2.25.1