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 4E30FFCB604 for ; Fri, 6 Mar 2026 14:47:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date: Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=ta3MggE09YbEyF7g4RimfGEhB0rCQXIJBNih2ThEo30=; b=isQcjAtlEhTeVGqvoItmSBAUAT WQCGEThrpJXFk4/M8L3DbRpJD061wJ0UrH43U6Z+Ed7PyLTCcFSE/O8uEU+lFgZ/Yelk3dFVkKUpG Nn6OOXKAjxTaHYFKNyyC47jedXLoOfCDYyd01JYdw1ZHHRElwSHdpQEt68k72TaClh68X69NpId/s nd7UmYCrMu4BBmRXvw9+X8/0CO6t/yXuh4LwV/8AspY1TDVLOgNORAOCa2afMl6fP+10jZ6l3P2wo EO31JJpH+PGOmkZODSLKGKKuuu9libYYXsZmE/i8OQIvYCuZNE+qvWCfRE7wY8rkK7vKXhI/Svtt4 gDOWiK0w==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vyWSy-00000003yA3-1GmO; Fri, 06 Mar 2026 14:47:48 +0000 Received: from tor.source.kernel.org ([172.105.4.254]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1vyWSw-00000003y9Y-1MWC for linux-arm-kernel@lists.infradead.org; Fri, 06 Mar 2026 14:47:46 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by tor.source.kernel.org (Postfix) with ESMTP id 59E1060018; Fri, 6 Mar 2026 14:47:45 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id DD48EC4CEF7; Fri, 6 Mar 2026 14:47:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1772808465; bh=nEGfcHcUpVbkDCHnZEP98qdqW1VIi3Dz6vL20ShVqGA=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=Rt2zzKKvlaFqYA8JPV2xqXEsBr54Bo4++L/xVH19cYqGVTItFEE0aVaSlbw3b21dR r2sGxgCFxYNvIm746EXbwl5pcLSAPRmYyMWSu9SsnNfA7jqZHZeHH4NxJZ0BIJrCoL qxbifJzo1/tXP4EdwwPmlhM1sdC990sSw0/asXJfqW5GlAYfYMNqmv3cBaW1d5a0LG RsLtHeS+snKmusuPnjjpAOEM6R1u18m5jDuYt3tH3ldjHY8G098wY1jCW8YhBtuwSH PgsueJiOD1d0k/TtS17AWBrta5G3iGwoPq5ObY9xIvaD/zOyO5nZlfpyrG/LAzh2eD tpwVYVgp928cw== Message-ID: <6305e05e-2911-42b0-b6f5-7fdde787b778@kernel.org> Date: Fri, 6 Mar 2026 15:47:35 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 6/6] arm64: mm: implement the architecture-specific test_and_clear_young_ptes() To: Baolin Wang , akpm@linux-foundation.org Cc: catalin.marinas@arm.com, will@kernel.org, lorenzo.stoakes@oracle.com, ryan.roberts@arm.com, Liam.Howlett@oracle.com, vbabka@suse.cz, rppt@kernel.org, surenb@google.com, mhocko@suse.com, riel@surriel.com, harry.yoo@oracle.com, jannh@google.com, willy@infradead.org, baohua@kernel.org, dev.jain@arm.com, axelrasmussen@google.com, yuanchu@google.com, weixugc@google.com, hannes@cmpxchg.org, zhengqi.arch@bytedance.com, shakeel.butt@linux.dev, linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org References: <7f891d42a720cc2e57862f3b79e4f774404f313c.1772778858.git.baolin.wang@linux.alibaba.com> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit 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: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 3/6/26 07:43, Baolin Wang wrote: > Implement the Arm64 architecture-specific test_and_clear_young_ptes() to enable > batched checking of young flags, improving performance during large folio > reclamation when MGLRU is enabled. > > While we're at it, simplify ptep_test_and_clear_young() by calling > test_and_clear_young_ptes(). Since callers guarantee that PTEs are present > before calling these functions, we can use pte_cont() to check the CONT_PTE > flag instead of pte_valid_cont(). > > Performance testing: > Enable MGLRU, then allocate 10G clean file-backed folios by mmap() in a memory > cgroup, and try to reclaim 8G file-backed folios via the memory.reclaim interface. > I can observe 60%+ performance improvement on my Arm64 32-core server (and about > 15% improvement on my X86 machine). > > W/o patchset: > real 0m0.470s > user 0m0.000s > sys 0m0.470s > > W/ patchset: > real 0m0.180s > user 0m0.001s > sys 0m0.179s > > Reviewed-by: Rik van Riel > Signed-off-by: Baolin Wang > --- > arch/arm64/include/asm/pgtable.h | 18 ++++++++++++------ > 1 file changed, 12 insertions(+), 6 deletions(-) > > diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h > index aa4b13da6371..ab451d20e4c5 100644 > --- a/arch/arm64/include/asm/pgtable.h > +++ b/arch/arm64/include/asm/pgtable.h > @@ -1812,16 +1812,22 @@ static inline pte_t ptep_get_and_clear(struct mm_struct *mm, > return __ptep_get_and_clear(mm, addr, ptep); > } > > +#define test_and_clear_young_ptes test_and_clear_young_ptes > +static inline int test_and_clear_young_ptes(struct vm_area_struct *vma, > + unsigned long addr, pte_t *ptep, > + unsigned int nr) > +{ > + if (likely(nr == 1 && !pte_cont(__ptep_get(ptep)))) > + return __ptep_test_and_clear_young(vma, addr, ptep); > + > + return contpte_test_and_clear_young_ptes(vma, addr, ptep, nr); > +} Thinking out loud, what would happen if (a) The range spans multiple possible cont ranges (like, 64 ptes). (b) The first pte is !pte_cont(), but some others in there are? -- Cheers, David