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 C5EA7C07E9D for ; Tue, 27 Sep 2022 02:56:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229623AbiI0Cz6 (ORCPT ); Mon, 26 Sep 2022 22:55:58 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44266 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229962AbiI0CzR (ORCPT ); Mon, 26 Sep 2022 22:55:17 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7710E275EA for ; Mon, 26 Sep 2022 19:50:10 -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 dfw.source.kernel.org (Postfix) with ESMTPS id 57644615B5 for ; Tue, 27 Sep 2022 02:50:10 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B32AFC433B5; Tue, 27 Sep 2022 02:50:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1664247009; bh=Bo0Kym92Jbpb8xEadCx1iNkXnHm4lPlt8LxKYt85azo=; h=Date:To:From:Subject:From; b=g8a4fhhSIzEnbopl1bXGITjbfeVlqd72uXKb0jOjbbvR6MVFICNHEmIkNq8MIuFZ0 gBLiBxgM9b0u296vMrq8isrvBy1sF4kxKjUWh1tBZcwW+SuyO8UxDlpARnHLuDGEuP ProB+9TmP3+GGSQnipRRkMscV2qfVddTpj5zqEAA= Date: Mon, 26 Sep 2022 19:50:09 -0700 To: mm-commits@vger.kernel.org, willy@infradead.org, vbabka@suse.cz, rostedt@goodmis.org, riel@surriel.com, peterz@infradead.org, mhocko@kernel.org, mgorman@techsingularity.net, liam.howlett@oracle.com, kirill@shutemov.name, hughd@google.com, matenajakub@gmail.com, akpm@linux-foundation.org From: Andrew Morton Subject: [merged mm-stable] mm-refactor-of-vma_merge.patch removed from -mm tree Message-Id: <20220927025009.B32AFC433B5@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: mm: refactor of vma_merge() has been removed from the -mm tree. Its filename was mm-refactor-of-vma_merge.patch This patch was dropped because it was merged into the mm-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: Jakub Matěna Subject: mm: refactor of vma_merge() Date: Fri, 3 Jun 2022 16:57:18 +0200 Patch series "Refactor of vma_merge and new merge call", v4. I am currently working on my master's thesis trying to increase number of merges of VMAs currently failing because of page offset incompatibility and difference in their anon_vmas. The following refactor and added merge call included in this series is just two smaller upgrades I created along the way. This patch (of 2): Refactor vma_merge() to make it shorter and more understandable. Main change is the elimination of code duplicity in the case of merge next check. This is done by first doing checks and caching the results before executing the merge itself. The variable 'area' is divided into 'mid' and 'res' as previously it was used for two purposes, as the middle VMA between prev and next and also as the result of the merge itself. Exit paths are also unified. Link: https://lkml.kernel.org/r/20220603145719.1012094-1-matenajakub@gmail.com Link: https://lkml.kernel.org/r/20220603145719.1012094-2-matenajakub@gmail.com Signed-off-by: Jakub Matěna Reviewed-by: Vlastimil Babka Cc: Michal Hocko Cc: Mel Gorman Cc: Matthew Wilcox Cc: Liam Howlett Cc: Hugh Dickins Cc: "Kirill A . Shutemov" Cc: Rik van Riel Cc: Steven Rostedt Cc: Peter Zijlstra (Intel) Signed-off-by: Andrew Morton --- mm/mmap.c | 87 ++++++++++++++++++++++------------------------------ 1 file changed, 37 insertions(+), 50 deletions(-) --- a/mm/mmap.c~mm-refactor-of-vma_merge +++ a/mm/mmap.c @@ -1005,8 +1005,10 @@ struct vm_area_struct *vma_merge(struct struct anon_vma_name *anon_name) { pgoff_t pglen = (end - addr) >> PAGE_SHIFT; - struct vm_area_struct *area, *next; - int err; + struct vm_area_struct *mid, *next, *res; + int err = -1; + bool merge_prev = false; + bool merge_next = false; /* * We later require that vma->vm_flags == vm_flags, @@ -1016,75 +1018,60 @@ struct vm_area_struct *vma_merge(struct return NULL; next = find_vma(mm, prev ? prev->vm_end : 0); - area = next; - if (area && area->vm_end == end) /* cases 6, 7, 8 */ + mid = next; + if (next && next->vm_end == end) /* cases 6, 7, 8 */ next = find_vma(mm, next->vm_end); /* verify some invariant that must be enforced by the caller */ VM_WARN_ON(prev && addr <= prev->vm_start); - VM_WARN_ON(area && end > area->vm_end); + VM_WARN_ON(mid && end > mid->vm_end); VM_WARN_ON(addr >= end); - /* - * Can it merge with the predecessor? - */ + /* Can we merge the predecessor? */ if (prev && prev->vm_end == addr && mpol_equal(vma_policy(prev), policy) && can_vma_merge_after(prev, vm_flags, anon_vma, file, pgoff, vm_userfaultfd_ctx, anon_name)) { - /* - * OK, it can. Can we now merge in the successor as well? - */ - if (next && end == next->vm_start && - mpol_equal(policy, vma_policy(next)) && - can_vma_merge_before(next, vm_flags, - anon_vma, file, - pgoff+pglen, - vm_userfaultfd_ctx, anon_name) && - is_mergeable_anon_vma(prev->anon_vma, - next->anon_vma, NULL)) { - /* cases 1, 6 */ - err = __vma_adjust(prev, prev->vm_start, - next->vm_end, prev->vm_pgoff, NULL, - prev); - } else /* cases 2, 5, 7 */ - err = __vma_adjust(prev, prev->vm_start, - end, prev->vm_pgoff, NULL, prev); - if (err) - return NULL; - khugepaged_enter_vma(prev, vm_flags); - return prev; + merge_prev = true; } - - /* - * Can this new request be merged in front of next? - */ + /* Can we merge the successor? */ if (next && end == next->vm_start && mpol_equal(policy, vma_policy(next)) && can_vma_merge_before(next, vm_flags, anon_vma, file, pgoff+pglen, vm_userfaultfd_ctx, anon_name)) { + merge_next = true; + } + /* Can we merge both the predecessor and the successor? */ + if (merge_prev && merge_next && + is_mergeable_anon_vma(prev->anon_vma, + next->anon_vma, NULL)) { /* cases 1, 6 */ + err = __vma_adjust(prev, prev->vm_start, + next->vm_end, prev->vm_pgoff, NULL, + prev); + res = prev; + } else if (merge_prev) { /* cases 2, 5, 7 */ + err = __vma_adjust(prev, prev->vm_start, + end, prev->vm_pgoff, NULL, prev); + res = prev; + } else if (merge_next) { if (prev && addr < prev->vm_end) /* case 4 */ err = __vma_adjust(prev, prev->vm_start, - addr, prev->vm_pgoff, NULL, next); - else { /* cases 3, 8 */ - err = __vma_adjust(area, addr, next->vm_end, - next->vm_pgoff - pglen, NULL, next); - /* - * In case 3 area is already equal to next and - * this is a noop, but in case 8 "area" has - * been removed and next was expanded over it. - */ - area = next; - } - if (err) - return NULL; - khugepaged_enter_vma(area, vm_flags); - return area; + addr, prev->vm_pgoff, NULL, next); + else /* cases 3, 8 */ + err = __vma_adjust(mid, addr, next->vm_end, + next->vm_pgoff - pglen, NULL, next); + res = next; } - return NULL; + /* + * Cannot merge with predecessor or successor or error in __vma_adjust? + */ + if (err) + return NULL; + khugepaged_enter_vma(res, vm_flags); + return res; } /* _ Patches currently in -mm which might be from matenajakub@gmail.com are