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 D4E95C433FE for ; Fri, 25 Mar 2022 22:43:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234042AbiCYWpT (ORCPT ); Fri, 25 Mar 2022 18:45:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57480 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234045AbiCYWpC (ORCPT ); Fri, 25 Mar 2022 18:45:02 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4C1F820E951 for ; Fri, 25 Mar 2022 15:43:17 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id F3518B82A35 for ; Fri, 25 Mar 2022 22:43:15 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A142AC340ED; Fri, 25 Mar 2022 22:43:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1648248194; bh=WygTcE6giWwVgYnYeUJLJo/xY8L3ltaPQeBb/K1ZyGg=; h=Date:To:From:Subject:From; b=Lu4X4Eck9mrXadd0T3Ikh1Hky9sgciqDX8sf7MrJJcklJcPKcZsQjXEZrIqiGRJjm PQYmZMSq45Ft9uW7AV7kkd8APyaqOi61gh0ayWvfdAJbyO0BPSHIM+5JyRkuhstFe6 ahZ+1LVWFy58ACGJdYGvDrwE+0jwJvWtRS+d1O9k= Date: Fri, 25 Mar 2022 15:43:14 -0700 To: mm-commits@vger.kernel.org, zhangliang5@huawei.com, willy@infradead.org, vbabka@suse.cz, shy828301@gmail.com, shakeelb@google.com, rppt@linux.ibm.com, roman.gushchin@linux.dev, rientjes@google.com, riel@surriel.com, peterx@redhat.com, oleg@redhat.com, nadav.amit@gmail.com, mike.kravetz@oracle.com, mhocko@kernel.org, kirill.shutemov@linux.intel.com, jhubbard@nvidia.com, jgg@nvidia.com, jannh@google.com, jack@suse.cz, hughd@google.com, hch@lst.de, ddutile@redhat.com, aarcange@redhat.com, david@redhat.com, akpm@linux-foundation.org From: Andrew Morton Subject: [merged] mm-khugepaged-remove-reuse_swap_page-usage.patch removed from -mm tree Message-Id: <20220325224314.A142AC340ED@smtp.kernel.org> Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org The patch titled Subject: mm/khugepaged: remove reuse_swap_page() usage has been removed from the -mm tree. Its filename was mm-khugepaged-remove-reuse_swap_page-usage.patch This patch was dropped because it was merged into mainline or a subsystem tree ------------------------------------------------------ From: David Hildenbrand Subject: mm/khugepaged: remove reuse_swap_page() usage reuse_swap_page() currently indicates if we can write to an anon page without COW. A COW is required if the page is shared by multiple processes (either already mapped or via swap entries) or if there is concurrent writeback that cannot tolerate concurrent page modifications. However, in the context of khugepaged we're not actually going to write to a read-only mapped page, we'll copy the page content to our newly allocated THP and map that THP writable. All we have to make sure is that the read-only mapped page we're about to copy won't get reused by another process sharing the page, otherwise, page content would get modified. But that is already guaranteed via multiple mechanisms (e.g., holding a reference, holding the page lock, removing the rmap after copying the page). The swapcache handling was introduced in commit 10359213d05a ("mm: incorporate read-only pages into transparent huge pages") and it sounds like it merely wanted to mimic what do_swap_page() would do when trying to map a page obtained via the swapcache writable. As that logic is unnecessary, let's just remove it, removing the last user of reuse_swap_page(). Link: https://lkml.kernel.org/r/20220131162940.210846-7-david@redhat.com Signed-off-by: David Hildenbrand Reviewed-by: Yang Shi Acked-by: Vlastimil Babka Cc: Andrea Arcangeli Cc: Christoph Hellwig Cc: David Rientjes Cc: Don Dutile Cc: Hugh Dickins Cc: Jan Kara Cc: Jann Horn Cc: Jason Gunthorpe Cc: John Hubbard Cc: Kirill A. Shutemov Cc: Liang Zhang Cc: Matthew Wilcox (Oracle) Cc: Michal Hocko Cc: Mike Kravetz Cc: Mike Rapoport Cc: Nadav Amit Cc: Oleg Nesterov Cc: Peter Xu Cc: Rik van Riel Cc: Roman Gushchin Cc: Shakeel Butt Signed-off-by: Andrew Morton --- include/trace/events/huge_memory.h | 1 - mm/khugepaged.c | 11 ----------- 2 files changed, 12 deletions(-) --- a/include/trace/events/huge_memory.h~mm-khugepaged-remove-reuse_swap_page-usage +++ a/include/trace/events/huge_memory.h @@ -29,7 +29,6 @@ EM( SCAN_VMA_NULL, "vma_null") \ EM( SCAN_VMA_CHECK, "vma_check_failed") \ EM( SCAN_ADDRESS_RANGE, "not_suitable_address_range") \ - EM( SCAN_SWAP_CACHE_PAGE, "page_swap_cache") \ EM( SCAN_DEL_PAGE_LRU, "could_not_delete_page_from_lru")\ EM( SCAN_ALLOC_HUGE_PAGE_FAIL, "alloc_huge_page_failed") \ EM( SCAN_CGROUP_CHARGE_FAIL, "ccgroup_charge_failed") \ --- a/mm/khugepaged.c~mm-khugepaged-remove-reuse_swap_page-usage +++ a/mm/khugepaged.c @@ -46,7 +46,6 @@ enum scan_result { SCAN_VMA_NULL, SCAN_VMA_CHECK, SCAN_ADDRESS_RANGE, - SCAN_SWAP_CACHE_PAGE, SCAN_DEL_PAGE_LRU, SCAN_ALLOC_HUGE_PAGE_FAIL, SCAN_CGROUP_CHARGE_FAIL, @@ -683,16 +682,6 @@ static int __collapse_huge_page_isolate( result = SCAN_PAGE_COUNT; goto out; } - if (!pte_write(pteval) && PageSwapCache(page) && - !reuse_swap_page(page)) { - /* - * Page is in the swap cache and cannot be re-used. - * It cannot be collapsed into a THP. - */ - unlock_page(page); - result = SCAN_SWAP_CACHE_PAGE; - goto out; - } /* * Isolate the page to avoid collapsing an hugepage _ Patches currently in -mm which might be from david@redhat.com are