From patchwork Tue Feb 13 21:55:19 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Zi Yan X-Patchwork-Id: 13555721 Received: from out5-smtp.messagingengine.com (out5-smtp.messagingengine.com [66.111.4.29]) (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 89E3462A1C; Tue, 13 Feb 2024 21:55:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=66.111.4.29 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707861354; cv=none; b=ug7aSTNkCSZhsdrM5R1OC2lsd8BIMRQSa3iBIDZBfNQQsWGcIhPolL2Y9ugeJKKLnGRtvIk8NqawxqfCw4Ym0zqxYF3+QDiZ5+LMdMmDxSpz+TDKPE3fWvMnc/FEhqODs4a9Z88W+Howsc1rngKQUg541sgS4S0m4BWLcxXf2KQ= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707861354; c=relaxed/simple; bh=OvAIGuwlGYeYczWW+K0KagfhK17treRqEU1nj29vKyk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=LhRI4XBX0SBYLpXHkIIWuC6bPHBVbi4SFa1mAR9BcpkdHP2dzPXoDCfq+s9dq685hPCJlSJ9bAZ2krr0nNtnOnlmerLAmV7Q4xNdZzDS2TeC97dun6KoP0whU5UyK1rgYrqkJfaR7KtKBUyhJBDc380OTkNYjkfWb40j6t8j2jY= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=sent.com; spf=pass smtp.mailfrom=sent.com; dkim=pass (2048-bit key) header.d=sent.com header.i=@sent.com header.b=WvLMGzG8; dkim=pass (2048-bit key) header.d=messagingengine.com header.i=@messagingengine.com header.b=sd8v5LS0; arc=none smtp.client-ip=66.111.4.29 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=sent.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=sent.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=sent.com header.i=@sent.com header.b="WvLMGzG8"; dkim=pass (2048-bit key) header.d=messagingengine.com header.i=@messagingengine.com header.b="sd8v5LS0" Received: from compute6.internal (compute6.nyi.internal [10.202.2.47]) by mailout.nyi.internal (Postfix) with ESMTP id 7B87D5C0117; Tue, 13 Feb 2024 16:55:51 -0500 (EST) Received: from mailfrontend2 ([10.202.2.163]) by compute6.internal (MEProxy); Tue, 13 Feb 2024 16:55:51 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sent.com; h=cc :cc:content-transfer-encoding:content-type:content-type:date :date:from:from:in-reply-to:in-reply-to:message-id:mime-version :references:reply-to:reply-to:subject:subject:to:to; s=fm3; t= 1707861351; x=1707947751; bh=oTNlS8iSN/pL1arvPd/5QTJjaetwy6e9fk4 UTiJDrr4=; b=WvLMGzG8wXGQ5WLFCyib254XrZQHLxadtOA5IFge31vgtZsUNbw FPxOtPftSxp73UoR9iEg0kRZSjAt3xVySIfSZPJZ+naXMvtREPI0U3qhxpCwOnqu wwMAdeHW4ZkZaro6be6Dqd0SALeZhxUxx/qjy5Bkw/ko2pogmrCh5Gh0XPG4e4kd dya0nrayzU3kjfIG4G00T9cPLYiLhzzsAz8mnQFVCyxAZ65g7Af73FntZ1IvA56I //RKnQY3tLcyiUYnnv4PzxhGicKR/FW8SnezFUktwatcPARjUIMdMF/G92989M6F oegvKTtsKcbbpLMFmwuQ52mp0uNLaz0pbZA== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:cc:content-transfer-encoding :content-type:content-type:date:date:feedback-id:feedback-id :from:from:in-reply-to:in-reply-to:message-id:mime-version :references:reply-to:reply-to:subject:subject:to:to:x-me-proxy :x-me-proxy:x-me-sender:x-me-sender:x-sasl-enc; s=fm3; t= 1707861351; x=1707947751; bh=oTNlS8iSN/pL1arvPd/5QTJjaetwy6e9fk4 UTiJDrr4=; b=sd8v5LS0k1pzxQL6VcVTcdNqUwTwF6t38tK/aSkdRt9DNR69YYW mgl3uyGhZ30NsrbitOLENl0DJQ2ZFqLAjEwrfl0soH7FXk90jzE7qFP38FVcL+M+ 4yjcb/L5toUeqbQW+1OeFqUN6+cxQNa2h5iKXgU8ITyuqdZn0m2lhUNtp8sscJkH 71gt5FNseF2R33sHskNxGOqZdSrEzuzUczAlVcw9KlQK7KCTx82uL61DXBoBG7/1 zb/Uxl+sqfZiUBXkoNgvExH/QammNJtjDbQg7c4N8sO7Y75+AIB7dzCV+RsHbai/ tkYuP3C6jL93ogiwew+KhZFSV9a/jRcl/AQ== X-ME-Sender: X-ME-Received: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgedvledrudehgdduheegucetufdoteggodetrfdotf fvucfrrhhofhhilhgvmecuhfgrshhtofgrihhlpdfqfgfvpdfurfetoffkrfgpnffqhgen uceurghilhhouhhtmecufedttdenucesvcftvggtihhpihgvnhhtshculddquddttddmne cujfgurhephffvvefufffkofgjfhhrgggtgfesthekredtredtjeenucfhrhhomhepkghi ucgjrghnuceoiihirdihrghnsehsvghnthdrtghomheqnecuggftrfgrthhtvghrnhepje ekteekffelleekudfftdefvddtjeejuedtuedtteegjefgvedtfedujeekieevnecuvehl uhhsthgvrhfuihiivgeptdenucfrrghrrghmpehmrghilhhfrhhomhepiihirdihrghnse hsvghnthdrtghomh X-ME-Proxy: Feedback-ID: iccd040f4:Fastmail Received: by mail.messagingengine.com (Postfix) with ESMTPA; Tue, 13 Feb 2024 16:55:50 -0500 (EST) From: Zi Yan To: "Pankaj Raghav (Samsung)" , linux-mm@kvack.org Cc: Zi Yan , "Matthew Wilcox (Oracle)" , David Hildenbrand , Yang Shi , Yu Zhao , "Kirill A . Shutemov" , Ryan Roberts , =?utf-8?q?Michal_Koutn=C3=BD?= , Roman Gushchin , "Zach O'Keefe" , Hugh Dickins , Mcgrof Chamberlain , Andrew Morton , linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kselftest@vger.kernel.org Subject: [PATCH v4 6/7] mm: truncate: split huge page cache page to a non-zero order if possible. Date: Tue, 13 Feb 2024 16:55:19 -0500 Message-ID: <20240213215520.1048625-7-zi.yan@sent.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240213215520.1048625-1-zi.yan@sent.com> References: <20240213215520.1048625-1-zi.yan@sent.com> Reply-To: Zi Yan Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: Zi Yan To minimize the number of pages after a huge page truncation, we do not need to split it all the way down to order-0. The huge page has at most three parts, the part before offset, the part to be truncated, the part remaining at the end. Find the greatest common divisor of them to calculate the new page order from it, so we can split the huge page to this order and keep the remaining pages as large and as few as possible. Signed-off-by: Zi Yan --- mm/truncate.c | 21 +++++++++++++++++++-- 1 file changed, 19 insertions(+), 2 deletions(-) diff --git a/mm/truncate.c b/mm/truncate.c index 725b150e47ac..49ddbbf7a617 100644 --- a/mm/truncate.c +++ b/mm/truncate.c @@ -21,6 +21,7 @@ #include #include #include +#include #include "internal.h" /* @@ -210,7 +211,8 @@ int truncate_inode_folio(struct address_space *mapping, struct folio *folio) bool truncate_inode_partial_folio(struct folio *folio, loff_t start, loff_t end) { loff_t pos = folio_pos(folio); - unsigned int offset, length; + unsigned int offset, length, remaining; + unsigned int new_order = folio_order(folio); if (pos < start) offset = start - pos; @@ -221,6 +223,7 @@ bool truncate_inode_partial_folio(struct folio *folio, loff_t start, loff_t end) length = length - offset; else length = end + 1 - pos - offset; + remaining = folio_size(folio) - offset - length; folio_wait_writeback(folio); if (length == folio_size(folio)) { @@ -235,11 +238,25 @@ bool truncate_inode_partial_folio(struct folio *folio, loff_t start, loff_t end) */ folio_zero_range(folio, offset, length); + /* + * Use the greatest common divisor of offset, length, and remaining + * as the smallest page size and compute the new order from it. So we + * can truncate a subpage as large as possible. Round up gcd to + * PAGE_SIZE, otherwise ilog2 can give -1 when gcd/PAGE_SIZE is 0. + */ + new_order = ilog2(round_up(gcd(gcd(offset, length), remaining), + PAGE_SIZE) / PAGE_SIZE); + + /* order-1 THP not supported, downgrade to order-0 */ + if (new_order == 1) + new_order = 0; + + if (folio_has_private(folio)) folio_invalidate(folio, offset, length); if (!folio_test_large(folio)) return true; - if (split_folio(folio) == 0) + if (split_huge_page_to_list_to_order(&folio->page, NULL, new_order) == 0) return true; if (folio_test_dirty(folio)) return false;