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 9DCDEE6B25F for ; Tue, 23 Dec 2025 05:49:11 +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: MIME-Version:Message-ID:Date:Subject:Cc:To:From:Reply-To:Content-Type: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References:List-Owner; bh=wurmuUfiWrJaqPqHxOTjUkR5eHzUJvLVCpRxkAiKRjc=; b=nMWNdppXzIeDnL+n+J1eBpnGsk RJ/pPlI44rMJkmJrzy/5kirgEgTDWlI4f6J+dDz8jvotDGEUSAC380MQVtG2Mm3PkzyK551TisR9X mQZuAvgRrVTVIpNTSmJ1kcmQKojOlAGcUSR1RaBKxogDnw6cwq025llRGMYP/CWngRMpIRwrP+cV0 itGjdQtMKDJ3wH2Jne4F7zWrd86rSoqEjzGxPT1WBeB20zHH2Yvrjx3x0yd5ZwmIOOgKv7wTGZL42 u2J7KG9Gmt4SSreOr5sH5qScuK1Cx7w+ZTfxKEZR4DRcfz/JC1np6192QzD5udmD95dsKf1CPLLw2 G6+NZoLA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vXvGd-0000000EZ6g-0gdp; Tue, 23 Dec 2025 05:49:07 +0000 Received: from out30-130.freemail.mail.aliyun.com ([115.124.30.130]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1vXvGS-0000000EZ1C-2aPJ for linux-arm-kernel@lists.infradead.org; Tue, 23 Dec 2025 05:49:00 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.alibaba.com; s=default; t=1766468929; h=From:To:Subject:Date:Message-ID:MIME-Version; bh=wurmuUfiWrJaqPqHxOTjUkR5eHzUJvLVCpRxkAiKRjc=; b=RoCargyQ62kTpiMWfKqm6gzVDXkbL684R/KQUW1e/VlpufhV8FrALoxeBgDVi8PuK2kqi/P3gBpcq0GX7UuvoISQtjSd92rdF5RDV2j52hzfCppgZ225Sv0sxSa2rtCgeiEJw1naqaGTIih8LABxoR7N28OYPjI3R0GRn7z2lis= Received: from localhost(mailfrom:baolin.wang@linux.alibaba.com fp:SMTPD_---0WvWX.R9_1766468923 cluster:ay36) by smtp.aliyun-inc.com; Tue, 23 Dec 2025 13:48:44 +0800 From: Baolin Wang To: akpm@linux-foundation.org, david@kernel.org, catalin.marinas@arm.com, will@kernel.org Cc: 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, baolin.wang@linux.alibaba.com, linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [PATCH v4 0/5] support batch checking of references and unmapping for large folios Date: Tue, 23 Dec 2025 13:48:34 +0800 Message-ID: X-Mailer: git-send-email 2.43.7 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20251222_214857_253385_A76DF391 X-CRM114-Status: GOOD ( 11.77 ) 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 Currently, folio_referenced_one() always checks the young flag for each PTE sequentially, which is inefficient for large folios. This inefficiency is especially noticeable when reclaiming clean file-backed large folios, where folio_referenced() is observed as a significant performance hotspot. Moreover, on Arm architecture, which supports contiguous PTEs, there is already an optimization to clear the young flags for PTEs within a contiguous range. However, this is not sufficient. We can extend this to perform batched operations for the entire large folio (which might exceed the contiguous range: CONT_PTE_SIZE). Similar to folio_referenced_one(), we can also apply batched unmapping for large file folios to optimize the performance of file folio reclamation. By supporting batched checking of the young flags, flushing TLB entries, and unmapping, I can observed a significant performance improvements in my performance tests for file folios reclamation. Please check the performance data in the commit message of each patch. Run stress-ng and mm selftests, no issues were found. Patch 1: Add a new generic batched PTE helper that supports batched checks of the references for large folios. Patch 2 - 3: Preparation patches. patch 4: Implement the Arm64 arch-specific clear_flush_young_ptes(). Patch 5: Support batched unmapping for file large folios. Changes from v3: - Fix using an incorrect parameter in ptep_clear_flush_young_notify() (per Liam). Changes from v2: - Rearrange the patch set (per Ryan). - Add pte_cont() check in clear_flush_young_ptes() (per Ryan). - Add a helper to do contpte block alignment (per Ryan). - Fix some coding style issues (per Lorenzo and Ryan). - Add more comments and update the commit message (per Lorenzo and Ryan). - Add acked tag from Barry. Thanks. Changes from v1: - Add a new patch to support batched unmapping for file large folios. - Update the cover letter Baolin Wang (5): mm: rmap: support batched checks of the references for large folios arm64: mm: factor out the address and ptep alignment into a new helper arm64: mm: support batch clearing of the young flag for large folios arm64: mm: implement the architecture-specific clear_flush_young_ptes() mm: rmap: support batched unmapping for file large folios arch/arm64/include/asm/pgtable.h | 23 ++++++++---- arch/arm64/mm/contpte.c | 62 ++++++++++++++++++++------------ include/linux/mmu_notifier.h | 9 ++--- include/linux/pgtable.h | 35 ++++++++++++++++++ mm/rmap.c | 36 ++++++++++++++++--- 5 files changed, 128 insertions(+), 37 deletions(-) -- 2.47.3