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 D9276FCB624 for ; Fri, 6 Mar 2026 23:20:55 +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:Mime-Version:References:In-Reply-To:Message-Id:Subject:Cc:To: From:Date:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=vdvaJB1LXFNDY6a15oc69M98GTl99EifvhmpoI/28Eg=; b=PN9jJIOJ/n1CG/M0OczxKIdRGB d0mO9dZch7hdUmh2K2W8zGafyITOEjQash13fWfr2zspLcxyy4keNtWiCZFLyhXveTGjpswBrK7kq NGXRUQ9SALq8j+nihEBf7v33D/E0G0If4gaHb5NHHW78IqaQe9V/MdlQjFcWwKSCFneYDh/w9fXdC Hr9PxlLJqwSJaOqV/Yv4X7SwjZtjGaYqB8DuWs5WYx5N4bTUomq2q3VknWQplwxb5ScMpYHMc4W7B ddN+0tF2YoYNRDIy8YI+hA1OI65hPO0NxRyRd6NcM5UIYpZFqz/gY4UvETJlgSNf1bPcV7rcsRKsz aUQaM/VQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vyeTQ-00000004dDB-2Rw9; Fri, 06 Mar 2026 23:20:48 +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 1vyeTO-00000004dCY-09qO for linux-arm-kernel@lists.infradead.org; Fri, 06 Mar 2026 23:20:46 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by tor.source.kernel.org (Postfix) with ESMTP id D945560053; Fri, 6 Mar 2026 23:20:44 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7DC82C4CEF7; Fri, 6 Mar 2026 23:20:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1772839244; bh=ax1SAYo+iTD471lZ8SZC4G6BL2Js8nhv7iBqCbhvGm0=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=IgOnLcroN+Cq4+uoc9rtF5U2JdkUFn/isXguriJYr4aQzvF25A5VeON8B+f31ceaY sxF4gZK9IF/xbEJi8UmLT5YkJqdECPNh7wKqzOYAy+udOV+IQEhKFAet4DKkkeRx9X X106S6MIa49lZe6PUl6PJ2LzW+cudcfxt3A1T4Xk= Date: Fri, 6 Mar 2026 15:20:42 -0800 From: Andrew Morton To: Baolin Wang Cc: david@kernel.org, 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 Subject: Re: [PATCH v3 0/6] support batched checking of the young flag for MGLRU Message-Id: <20260306152042.8516ec644e95e9a23df30e5f@linux-foundation.org> In-Reply-To: References: X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII 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 Fri, 6 Mar 2026 14:43:36 +0800 Baolin Wang wrote: > This is a follow-up to the previous work [1], to support batched checking > of the young flag for MGLRU. > > Similarly, batched checking of young flag for large folios can improve > performance during large-folio reclamation when MGLRU is enabled. I > observed noticeable performance improvements (see patch 5) on an Arm64 > machine that supports contiguous PTEs. All mm-selftests are passed. Thanks, I updated mm-new with this. > Changes from v2: > v2: https://lore.kernel.org/all/cover.1772185080.git.baolin.wang@linux.alibaba.com/ > - Update the commit message of patch 5 (per David). > - Fix some coding style issues (per David). > - Remove 'cur_pte' variable in lru_gen_look_around() (per David). > - Move 'ptes += nr;' to the suitable place in folio_referenced_one() (per David). > - Add acked tag from David. Thanks. > Here's how v3 altered mm.git: include/linux/pgtable.h | 3 +-- mm/rmap.c | 2 +- mm/vmscan.c | 11 +++++------ 3 files changed, 7 insertions(+), 9 deletions(-) --- a/include/linux/pgtable.h~b +++ a/include/linux/pgtable.h @@ -1124,8 +1124,7 @@ static inline int clear_flush_young_ptes * Returns: whether any PTE was young. */ static inline int test_and_clear_young_ptes(struct vm_area_struct *vma, - unsigned long addr, pte_t *ptep, - unsigned int nr) + unsigned long addr, pte_t *ptep, unsigned int nr) { int young = 0; --- a/mm/rmap.c~b +++ a/mm/rmap.c @@ -964,7 +964,6 @@ static bool folio_referenced_one(struct pte_t pteval = ptep_get(pvmw.pte); nr = folio_pte_batch(folio, pvmw.pte, pteval, max_nr); - ptes += nr; } if (lru_gen_enabled() && pvmw.pte) { @@ -982,6 +981,7 @@ static bool folio_referenced_one(struct WARN_ON_ONCE(1); } + ptes += nr; pra->mapcount -= nr; /* * If we are sure that we batched the entire folio, --- a/mm/vmscan.c~b +++ a/mm/vmscan.c @@ -4201,7 +4201,6 @@ bool lru_gen_look_around(struct page_vma struct lruvec *lruvec; struct lru_gen_mm_state *mm_state; unsigned long max_seq; - pte_t *cur_pte; int gen; lockdep_assert_held(pvmw->ptl); @@ -4247,10 +4246,10 @@ bool lru_gen_look_around(struct page_vma pte -= (addr - start) / PAGE_SIZE; - for (i = 0, addr = start, cur_pte = pte; addr != end; - i += nr, cur_pte += nr, addr += nr * PAGE_SIZE) { + for (i = 0, addr = start; addr != end; + i += nr, pte += nr, addr += nr * PAGE_SIZE) { unsigned long pfn; - pte_t ptent = ptep_get(cur_pte); + pte_t ptent = ptep_get(pte); nr = 1; pfn = get_pte_pfn(ptent, vma, addr, pgdat); @@ -4264,11 +4263,11 @@ bool lru_gen_look_around(struct page_vma if (folio_test_large(folio)) { const unsigned int max_nr = (end - addr) >> PAGE_SHIFT; - nr = folio_pte_batch_flags(folio, NULL, cur_pte, &ptent, + nr = folio_pte_batch_flags(folio, NULL, pte, &ptent, max_nr, FPB_MERGE_YOUNG_DIRTY); } - if (!test_and_clear_young_ptes_notify(vma, addr, cur_pte, nr)) + if (!test_and_clear_young_ptes_notify(vma, addr, pte, nr)) continue; if (last != folio) { _