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 6E25EC83003 for ; Thu, 24 Aug 2023 22:00:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243789AbjHXWA1 (ORCPT ); Thu, 24 Aug 2023 18:00:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53942 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243840AbjHXWAW (ORCPT ); Thu, 24 Aug 2023 18:00:22 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 215FF1BF7 for ; Thu, 24 Aug 2023 15:00:18 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id B0D176342E for ; Thu, 24 Aug 2023 22:00:17 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1297DC433C7; Thu, 24 Aug 2023 22:00:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1692914417; bh=JudMi9YzUpUmPZI11hGYYHRZcRgGKZt34hYMgLwx86Q=; h=Date:To:From:Subject:From; b=g7Sg4snc3ZEePbfQwb7N9g/GeVwpE8qvDvOZJGkztntmNvQ5BoW1w0mSKBy4JQqo4 Zt2oQqCe86pun/stabNoqa9eUVgoQqqlcWERyVGhAlz+M+QBSMQq+fTt8W3aL621oM DDVsfuZ3k217Q7jlfiTV6C7J1uZ2RkdgAblk/i5Y= Date: Thu, 24 Aug 2023 15:00:16 -0700 To: mm-commits@vger.kernel.org, yuzhao@google.com, willy@infradead.org, wangkefeng.wang@huawei.com, vishal.moola@gmail.com, shy828301@gmail.com, ryan.roberts@arm.com, minchan@kernel.org, david@redhat.com, fengwei.yin@intel.com, akpm@linux-foundation.org From: Andrew Morton Subject: [merged mm-hotfixes-stable] madvise-madvise_free_huge_pmd-dont-use-mapcount-against-large-folio-for-sharing-check.patch removed from -mm tree Message-Id: <20230824220017.1297DC433C7@smtp.kernel.org> Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org The quilt patch titled Subject: madvise:madvise_free_huge_pmd(): don't use mapcount() against large folio for sharing check has been removed from the -mm tree. Its filename was madvise-madvise_free_huge_pmd-dont-use-mapcount-against-large-folio-for-sharing-check.patch This patch was dropped because it was merged into the mm-hotfixes-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: Yin Fengwei Subject: madvise:madvise_free_huge_pmd(): don't use mapcount() against large folio for sharing check Date: Tue, 8 Aug 2023 10:09:16 +0800 Commit fc986a38b670 ("mm: huge_memory: convert madvise_free_huge_pmd to use a folio") replaced the page_mapcount() with folio_mapcount() to check whether the folio is shared by other mapping. It's not correct for large folios. folio_mapcount() returns the total mapcount of large folio which is not suitable to detect whether the folio is shared. Use folio_estimated_sharers() which returns a estimated number of shares. That means it's not 100% correct. It should be OK for madvise case here. User-visible effects is that the THP is skipped when user call madvise. But the correct behavior is THP should be split and processed then. NOTE: this change is a temporary fix to reduce the user-visible effects before the long term fix from David is ready. Link: https://lkml.kernel.org/r/20230808020917.2230692-3-fengwei.yin@intel.com Fixes: fc986a38b670 ("mm: huge_memory: convert madvise_free_huge_pmd to use a folio") Signed-off-by: Yin Fengwei Reviewed-by: Yu Zhao Reviewed-by: Ryan Roberts Cc: David Hildenbrand Cc: Kefeng Wang Cc: Matthew Wilcox Cc: Minchan Kim Cc: Vishal Moola (Oracle) Cc: Yang Shi Signed-off-by: Andrew Morton --- mm/huge_memory.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/mm/huge_memory.c~madvise-madvise_free_huge_pmd-dont-use-mapcount-against-large-folio-for-sharing-check +++ a/mm/huge_memory.c @@ -1612,7 +1612,7 @@ bool madvise_free_huge_pmd(struct mmu_ga * If other processes are mapping this folio, we couldn't discard * the folio unless they all do MADV_FREE so let's skip the folio. */ - if (folio_mapcount(folio) != 1) + if (folio_estimated_sharers(folio) != 1) goto out; if (!folio_trylock(folio)) _ Patches currently in -mm which might be from fengwei.yin@intel.com are filemap-add-filemap_map_folio_range.patch rmap-add-folio_add_file_rmap_range.patch mm-convert-do_set_pte-to-set_pte_range.patch filemap-batch-pte-mappings.patch