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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id F3793EB64D9 for ; Mon, 10 Jul 2023 05:39:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229875AbjGJFjT (ORCPT ); Mon, 10 Jul 2023 01:39:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45752 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229458AbjGJFjQ (ORCPT ); Mon, 10 Jul 2023 01:39:16 -0400 Received: from mga09.intel.com (mga09.intel.com [134.134.136.24]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 53476B3 for ; Sun, 9 Jul 2023 22:39:15 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1688967555; x=1720503555; h=from:to:cc:subject:references:date:in-reply-to: message-id:mime-version; bh=Ys8L0Hbye36COw2RYLz/SroMuaxGWFfQb1sQCRJw2nM=; b=VbnklF0YH6N5cAfiENU33UHWPYZd1mYJ9/Kcn7bmfCNmYMuapUywq5i3 kr37IArI4ZABCWUKrM3N9GikaljKOR3vRjINsyNsg4qlUilzAVVT8Juho G+RLtrCFVlHA9AOt0wUFNw1xsJEhf6NG0lmyOtuqI+dMaXvfF/gqoxEzv EEp7hmsbFRPNYVYffkEPx8ZtdIqYhczcbWRf08egcvxMr4d9KiM9F3mHt ozLgfn+DXCC+RhwKlyWQNu0MOeMUo0ruTDE/tkzinQj1ZaJ8UCTvkDZ8O ZfTGbDaTuOW+6PPctC7Wz7nqxc5uEEo0EDXwLFS9ds8dFqkEoQZZTN8S+ w==; X-IronPort-AV: E=McAfee;i="6600,9927,10766"; a="366839046" X-IronPort-AV: E=Sophos;i="6.01,194,1684825200"; d="scan'208";a="366839046" Received: from fmsmga006.fm.intel.com ([10.253.24.20]) by orsmga102.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 09 Jul 2023 22:39:14 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10766"; a="967312758" X-IronPort-AV: E=Sophos;i="6.01,194,1684825200"; d="scan'208";a="967312758" Received: from yhuang6-desk2.sh.intel.com (HELO yhuang6-desk2.ccr.corp.intel.com) ([10.238.208.55]) by fmsmga006-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 09 Jul 2023 22:39:11 -0700 From: "Huang, Ying" To: Ryan Roberts Cc: Andrew Morton , Matthew Wilcox , "Kirill A. Shutemov" , Yin Fengwei , "David Hildenbrand" , Yu Zhao , "Catalin Marinas" , Will Deacon , "Anshuman Khandual" , Yang Shi , , , Subject: Re: [PATCH v2 2/5] mm: Allow deferred splitting of arbitrary large anon folios References: <20230703135330.1865927-1-ryan.roberts@arm.com> <20230703135330.1865927-3-ryan.roberts@arm.com> <877crcgmj1.fsf@yhuang6-desk2.ccr.corp.intel.com> <6379dd13-551e-3c73-422a-56ce40b27deb@arm.com> Date: Mon, 10 Jul 2023 13:37:24 +0800 In-Reply-To: <6379dd13-551e-3c73-422a-56ce40b27deb@arm.com> (Ryan Roberts's message of "Fri, 7 Jul 2023 10:42:26 +0100") Message-ID: <87ttucfht7.fsf@yhuang6-desk2.ccr.corp.intel.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/28.2 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=ascii Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Ryan Roberts writes: > Somehow I managed to reply only to the linux-arm-kernel list on first attempt so > resending: > > On 07/07/2023 09:21, Huang, Ying wrote: >> Ryan Roberts writes: >> >>> With the introduction of large folios for anonymous memory, we would >>> like to be able to split them when they have unmapped subpages, in order >>> to free those unused pages under memory pressure. So remove the >>> artificial requirement that the large folio needed to be at least >>> PMD-sized. >>> >>> Signed-off-by: Ryan Roberts >>> Reviewed-by: Yu Zhao >>> Reviewed-by: Yin Fengwei >>> --- >>> mm/rmap.c | 2 +- >>> 1 file changed, 1 insertion(+), 1 deletion(-) >>> >>> diff --git a/mm/rmap.c b/mm/rmap.c >>> index 82ef5ba363d1..bbcb2308a1c5 100644 >>> --- a/mm/rmap.c >>> +++ b/mm/rmap.c >>> @@ -1474,7 +1474,7 @@ void page_remove_rmap(struct page *page, struct vm_area_struct *vma, >>> * page of the folio is unmapped and at least one page >>> * is still mapped. >>> */ >>> - if (folio_test_pmd_mappable(folio) && folio_test_anon(folio)) >>> + if (folio_test_large(folio) && folio_test_anon(folio)) >>> if (!compound || nr < nr_pmdmapped) >>> deferred_split_folio(folio); >>> } >> >> One possible issue is that even for large folios mapped only in one >> process, in zap_pte_range(), we will always call deferred_split_folio() >> unnecessarily before freeing a large folio. > > Hi Huang, thanks for reviewing! > > I have a patch that solves this problem by determining a range of ptes covered > by a single folio and doing a "batch zap". This prevents the need to add the > folio to the deferred split queue, only to remove it again shortly afterwards. > This reduces lock contention and I can measure a performance improvement for the > kernel compilation benchmark. See [1]. > > However, I decided to remove it from this patch set on Yu Zhao's advice. We are > aiming for the minimal patch set to start with and wanted to focus people on > that. I intend to submit it separately later on. > > [1] https://lore.kernel.org/linux-mm/20230626171430.3167004-8-ryan.roberts@arm.com/ Thanks for your information! "batch zap" can solve the problem. And, I agree with Matthew's comments to fix the large folios interaction issues before merging the patches to allocate large folios as in the following email. https://lore.kernel.org/linux-mm/ZKVdUDuwNWDUCWc5@casper.infradead.org/ If so, we don't need to introduce the above problem or a large patchset. Best Regards, Huang, Ying 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 184C7EB64D9 for ; Mon, 10 Jul 2023 05:39:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:Message-ID:In-Reply-To: Date:References:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=NLnrhSZBo7tLSIfKxcDIjqY52GWsxoIDAdu8IAfTHSA=; b=Gkt5GsOWzpbyai fFGqVQY+DxBZin5SCXEGgKuFWPjycptg3290G8mmT64vfDhQ7mVZxysxnc3Fh9tqlJ7MOPk655Xzp /iyPgNKbGJVFnjW55+SvAJKsFH2nUxVeLH+tQ1eyuC2/3DDD9dbCCiqZ0a0RqhFlKgqi8/aOmUs8C ZvSZEYGoHGUjfYCaf4GYQGKGAFztawPsRy7P5F5uNj40LtZfItBbtuLdgrRCrAI1ep2xjAiHkixuq KRWOygywljp5O8WH1jbTslcJMdjmLGDzui3xA2VJdwQpuQUwsT7MFD8hUEqd9XRn33EMhBEPmAl2k 7pQn2KEfpG5LANfRjoig==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1qIjcE-00AUZ9-25; Mon, 10 Jul 2023 05:39:18 +0000 Received: from mga09.intel.com ([134.134.136.24]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1qIjcB-00AUXv-1y for linux-arm-kernel@lists.infradead.org; Mon, 10 Jul 2023 05:39:17 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1688967555; x=1720503555; h=from:to:cc:subject:references:date:in-reply-to: message-id:mime-version; bh=Ys8L0Hbye36COw2RYLz/SroMuaxGWFfQb1sQCRJw2nM=; b=VbnklF0YH6N5cAfiENU33UHWPYZd1mYJ9/Kcn7bmfCNmYMuapUywq5i3 kr37IArI4ZABCWUKrM3N9GikaljKOR3vRjINsyNsg4qlUilzAVVT8Juho G+RLtrCFVlHA9AOt0wUFNw1xsJEhf6NG0lmyOtuqI+dMaXvfF/gqoxEzv EEp7hmsbFRPNYVYffkEPx8ZtdIqYhczcbWRf08egcvxMr4d9KiM9F3mHt ozLgfn+DXCC+RhwKlyWQNu0MOeMUo0ruTDE/tkzinQj1ZaJ8UCTvkDZ8O ZfTGbDaTuOW+6PPctC7Wz7nqxc5uEEo0EDXwLFS9ds8dFqkEoQZZTN8S+ w==; X-IronPort-AV: E=McAfee;i="6600,9927,10766"; a="366839048" X-IronPort-AV: E=Sophos;i="6.01,194,1684825200"; d="scan'208";a="366839048" Received: from fmsmga006.fm.intel.com ([10.253.24.20]) by orsmga102.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 09 Jul 2023 22:39:14 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10766"; a="967312758" X-IronPort-AV: E=Sophos;i="6.01,194,1684825200"; d="scan'208";a="967312758" Received: from yhuang6-desk2.sh.intel.com (HELO yhuang6-desk2.ccr.corp.intel.com) ([10.238.208.55]) by fmsmga006-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 09 Jul 2023 22:39:11 -0700 From: "Huang, Ying" To: Ryan Roberts Cc: Andrew Morton , Matthew Wilcox , "Kirill A. Shutemov" , Yin Fengwei , "David Hildenbrand" , Yu Zhao , "Catalin Marinas" , Will Deacon , "Anshuman Khandual" , Yang Shi , , , Subject: Re: [PATCH v2 2/5] mm: Allow deferred splitting of arbitrary large anon folios References: <20230703135330.1865927-1-ryan.roberts@arm.com> <20230703135330.1865927-3-ryan.roberts@arm.com> <877crcgmj1.fsf@yhuang6-desk2.ccr.corp.intel.com> <6379dd13-551e-3c73-422a-56ce40b27deb@arm.com> Date: Mon, 10 Jul 2023 13:37:24 +0800 In-Reply-To: <6379dd13-551e-3c73-422a-56ce40b27deb@arm.com> (Ryan Roberts's message of "Fri, 7 Jul 2023 10:42:26 +0100") Message-ID: <87ttucfht7.fsf@yhuang6-desk2.ccr.corp.intel.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/28.2 (gnu/linux) MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230709_223915_740802_2FBB8AAC X-CRM114-Status: GOOD ( 23.92 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Ryan Roberts writes: > Somehow I managed to reply only to the linux-arm-kernel list on first attempt so > resending: > > On 07/07/2023 09:21, Huang, Ying wrote: >> Ryan Roberts writes: >> >>> With the introduction of large folios for anonymous memory, we would >>> like to be able to split them when they have unmapped subpages, in order >>> to free those unused pages under memory pressure. So remove the >>> artificial requirement that the large folio needed to be at least >>> PMD-sized. >>> >>> Signed-off-by: Ryan Roberts >>> Reviewed-by: Yu Zhao >>> Reviewed-by: Yin Fengwei >>> --- >>> mm/rmap.c | 2 +- >>> 1 file changed, 1 insertion(+), 1 deletion(-) >>> >>> diff --git a/mm/rmap.c b/mm/rmap.c >>> index 82ef5ba363d1..bbcb2308a1c5 100644 >>> --- a/mm/rmap.c >>> +++ b/mm/rmap.c >>> @@ -1474,7 +1474,7 @@ void page_remove_rmap(struct page *page, struct vm_area_struct *vma, >>> * page of the folio is unmapped and at least one page >>> * is still mapped. >>> */ >>> - if (folio_test_pmd_mappable(folio) && folio_test_anon(folio)) >>> + if (folio_test_large(folio) && folio_test_anon(folio)) >>> if (!compound || nr < nr_pmdmapped) >>> deferred_split_folio(folio); >>> } >> >> One possible issue is that even for large folios mapped only in one >> process, in zap_pte_range(), we will always call deferred_split_folio() >> unnecessarily before freeing a large folio. > > Hi Huang, thanks for reviewing! > > I have a patch that solves this problem by determining a range of ptes covered > by a single folio and doing a "batch zap". This prevents the need to add the > folio to the deferred split queue, only to remove it again shortly afterwards. > This reduces lock contention and I can measure a performance improvement for the > kernel compilation benchmark. See [1]. > > However, I decided to remove it from this patch set on Yu Zhao's advice. We are > aiming for the minimal patch set to start with and wanted to focus people on > that. I intend to submit it separately later on. > > [1] https://lore.kernel.org/linux-mm/20230626171430.3167004-8-ryan.roberts@arm.com/ Thanks for your information! "batch zap" can solve the problem. And, I agree with Matthew's comments to fix the large folios interaction issues before merging the patches to allocate large folios as in the following email. https://lore.kernel.org/linux-mm/ZKVdUDuwNWDUCWc5@casper.infradead.org/ If so, we don't need to introduce the above problem or a large patchset. Best Regards, Huang, Ying _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel