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 X-Spam-Level: X-Spam-Status: No, score=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_RED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D5AC7C11F68 for ; Thu, 1 Jul 2021 01:52:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B745C61476 for ; Thu, 1 Jul 2021 01:52:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238483AbhGAByf (ORCPT ); Wed, 30 Jun 2021 21:54:35 -0400 Received: from mail.kernel.org ([198.145.29.99]:44096 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238418AbhGAByf (ORCPT ); Wed, 30 Jun 2021 21:54:35 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 1F6AC61474; Thu, 1 Jul 2021 01:52:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1625104325; bh=YB2daD+Wi9X9GUd02UzY33OL+VvqiKaf8fIYoCEIhWI=; h=Date:From:To:Subject:In-Reply-To:From; b=XQjRMY9NR1mTaY75pRRee5NtCerDPlMRm5CeNigaZsL6V6o7/3Nw6gtgqAHtaB/Gy BBxpPXQW6Ymk0Q4MMBo09JbOx+5J8T/5hgT+Vf5wTnS9vg1DellVu6cqMaqVfmnib6 Mi8+9Z7Mb55Suwh5zPgs3pa2scO8kHWkWmUS4ANw= Date: Wed, 30 Jun 2021 18:52:04 -0700 From: Andrew Morton To: akpm@linux-foundation.org, apopple@nvidia.com, hughd@google.com, jack@suse.cz, juew@google.com, kirill.shutemov@linux.intel.com, linmiaohe@huawei.com, linux-mm@kvack.org, minchan@kernel.org, mm-commits@vger.kernel.org, naoya.horiguchi@nec.com, osalvador@suse.de, peterx@redhat.com, rcampbell@nvidia.com, shakeelb@google.com, shy828301@gmail.com, torvalds@linux-foundation.org, wangyugui@e16-tech.com, willy@infradead.org, ziy@nvidia.com Subject: [patch 092/192] mm/thp: remap_page() is only needed on anonymous THP Message-ID: <20210701015204.PUckIgqJ6%akpm@linux-foundation.org> In-Reply-To: <20210630184624.9ca1937310b0dd5ce66b30e7@linux-foundation.org> User-Agent: s-nail v14.8.16 Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org From: Hugh Dickins Subject: mm/thp: remap_page() is only needed on anonymous THP THP splitting's unmap_page() only sets TTU_SPLIT_FREEZE when PageAnon, and migration entries are only inserted when TTU_MIGRATION (unused here) or TTU_SPLIT_FREEZE is set: so it's just a waste of time for remap_page() to search for migration entries to remove when !PageAnon. Link: https://lkml.kernel.org/r/f987bc44-f28e-688d-2424-b4722153ed8@google.com Fixes: baa355fd3314 ("thp: file pages support for split_huge_page()") Signed-off-by: Hugh Dickins Reviewed-by: Yang Shi Acked-by: Kirill A. Shutemov Cc: Alistair Popple Cc: Jan Kara Cc: Jue Wang Cc: "Matthew Wilcox (Oracle)" Cc: Miaohe Lin Cc: Minchan Kim Cc: Naoya Horiguchi Cc: Oscar Salvador Cc: Peter Xu Cc: Ralph Campbell Cc: Shakeel Butt Cc: Wang Yugui Cc: Zi Yan Signed-off-by: Andrew Morton --- mm/huge_memory.c | 5 +++++ 1 file changed, 5 insertions(+) --- a/mm/huge_memory.c~mm-thp-remap_page-is-only-needed-on-anonymous-thp +++ a/mm/huge_memory.c @@ -2307,6 +2307,7 @@ static void unmap_page(struct page *page VM_BUG_ON_PAGE(!PageHead(page), page); + /* If TTU_SPLIT_FREEZE is ever extended to file, update remap_page() */ if (PageAnon(page)) ttu_flags |= TTU_SPLIT_FREEZE; @@ -2318,6 +2319,10 @@ static void unmap_page(struct page *page static void remap_page(struct page *page, unsigned int nr) { int i; + + /* If TTU_SPLIT_FREEZE is ever extended to file, remove this check */ + if (!PageAnon(page)) + return; if (PageTransHuge(page)) { remove_migration_ptes(page, page, true); } else { _