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 24544C83F16 for ; Sat, 26 Aug 2023 20:27:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229652AbjHZU0r (ORCPT ); Sat, 26 Aug 2023 16:26:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57966 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229599AbjHZU0U (ORCPT ); Sat, 26 Aug 2023 16:26:20 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A2046CF1 for ; Sat, 26 Aug 2023 13:26:18 -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 37BAB60B45 for ; Sat, 26 Aug 2023 20:26:18 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2188AC433C8; Sat, 26 Aug 2023 20:26:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1693081577; bh=qUxDLc956QYAb5+fVSrDz/yn3jjuCDoRCuyJi2u0074=; h=Subject:To:Cc:From:Date:From; b=dUx19gz/3dneXwJhRWJ1aoQZo83fWREgvULLiIbTCTeNpIt7oEH1K6NzKKxw/hEkB 1yeePczCNfwKj0vBTl6p80TO+MHIF8dW7dM3MVbATdt9QEqME+pYPN7j3k/S0q0TL3 E6crfZyOoxUQgnhRBo+0ixQUwkHd9o3m4ncBQS/c= Subject: FAILED: patch "[PATCH] madvise:madvise_free_pte_range(): don't use mapcount()" failed to apply to 6.4-stable tree To: fengwei.yin@intel.com, akpm@linux-foundation.org, david@redhat.com, minchan@kernel.org, ryan.roberts@arm.com, shy828301@gmail.com, stable@vger.kernel.org, vishal.moola@gmail.com, wangkefeng.wang@huawei.com, willy@infradead.org, yuzhao@google.com Cc: From: Date: Sat, 26 Aug 2023 22:26:14 +0200 Message-ID: <2023082614-choice-mongoose-0731@gregkh> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org The patch below does not apply to the 6.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.4.y git checkout FETCH_HEAD git cherry-pick -x 0e0e9bd5f7b9d40fd03b70092367247d52da1db0 # git commit -s git send-email --to '' --in-reply-to '2023082614-choice-mongoose-0731@gregkh' --subject-prefix 'PATCH 6.4.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 0e0e9bd5f7b9d40fd03b70092367247d52da1db0 Mon Sep 17 00:00:00 2001 From: Yin Fengwei Date: Tue, 8 Aug 2023 10:09:17 +0800 Subject: [PATCH] madvise:madvise_free_pte_range(): don't use mapcount() against large folio for sharing check Commit 98b211d6415f ("madvise: convert madvise_free_pte_range() 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/20230808020917.2230692-4-fengwei.yin@intel.com Fixes: 98b211d6415f ("madvise: convert madvise_free_pte_range() 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 Cc: Signed-off-by: Andrew Morton diff --git a/mm/madvise.c b/mm/madvise.c index 46802b4cf65a..ec30f48f8f2e 100644 --- a/mm/madvise.c +++ b/mm/madvise.c @@ -680,7 +680,7 @@ static int madvise_free_pte_range(pmd_t *pmd, unsigned long addr, if (folio_test_large(folio)) { int err; - if (folio_mapcount(folio) != 1) + if (folio_estimated_sharers(folio) != 1) break; if (!folio_trylock(folio)) break;