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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1021DC433EF for ; Fri, 18 Feb 2022 12:21:43 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 0DB106B007B; Fri, 18 Feb 2022 07:21:40 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 03CB56B007D; Fri, 18 Feb 2022 07:21:39 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id DACA36B007E; Fri, 18 Feb 2022 07:21:39 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0192.hostedemail.com [216.40.44.192]) by kanga.kvack.org (Postfix) with ESMTP id A5F206B007D for ; Fri, 18 Feb 2022 07:21:39 -0500 (EST) Received: from smtpin29.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 6574F181AC9C6 for ; Fri, 18 Feb 2022 12:21:39 +0000 (UTC) X-FDA: 79155811518.29.A5A5407 Received: from mail-ed1-f52.google.com (mail-ed1-f52.google.com [209.85.208.52]) by imf10.hostedemail.com (Postfix) with ESMTP id B2247C0002 for ; Fri, 18 Feb 2022 12:21:38 +0000 (UTC) Received: by mail-ed1-f52.google.com with SMTP id i11so13500365eda.9 for ; Fri, 18 Feb 2022 04:21:38 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=hmEc5DoCLSD2DUJvNGydFX4svqDfjOrJL7x2lrpSPLk=; b=CcKCLBaPT80Z0Ha52pupsWCnMFYXy7bgQULIdXfwDMH9jGcQoTvbLhQ9wMsEkGrUgP y5KLlTAyZVa/I6W8kzmGg5ctllfTE795LOkwk/yBXxnqUVyaEbEwS0TyMmmmF/bApkW3 JqfgOlbiYOuaouOsfd7tW1W4NndVQAwtd4xCYdp86nQ5J2uaX7Jh1226vYXxGmdRXCno SD/1NEm9WtU8Ex1H1w902lw0xa8IGuYrYaMM1hVIqutF7UM17ahpcD6BNJFHMqHf1x0z egOQh3b2d/znJRXCmaxrTdCwxJRY/z8W8f3FSvwpPrQuoQf57cpnENtcKT5nIkvJ6F21 1xTA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=hmEc5DoCLSD2DUJvNGydFX4svqDfjOrJL7x2lrpSPLk=; b=OtdQCyGoATrAar6Sfv3YCA9KeTcNVizj7Ru/3SH2alrt31oMZW8bwnH925HDuMbf7J mBuId2TDhpn7nC1z29QgwYkes7fXIR6Nn3AukDYIDImmU2pgakCIlCu7649c5wvPaa3y WKs2jRVhrC9Ll7V9y1M0Q3EqiR4VKpeLPvNsAo0tJqQixjDJknO6VJVmNIPlcb0jh8Cc ifyUpy4U/FE1tpI+qJM21h3l+76twLoKb/EE7ZpPGG4cK2IuzBV1qo6ZPTUNar9SYjXx PW/bPzqbBsjK0lWo2XK3Lk9jK3F1t9wj0Z6jhBPNgS3rI3FlqXZ5oFj90sGk/+ZvSaK4 7+hA== X-Gm-Message-State: AOAM532++PwKQJFp36p+ywC5w+QR6c6B+M1pa8f3REkZoe3ysFMrPvts Lq1XgLKSEI+BYQZ1e5Rw/O0= X-Google-Smtp-Source: ABdhPJwVNqS56OqHGXAdnjOIi2ZizE0j3EbD6E/PqQm5nKLAxCraATH7mQWAOpRduhttWtSq1TRS0g== X-Received: by 2002:a50:9b12:0:b0:410:b926:d2d3 with SMTP id o18-20020a509b12000000b00410b926d2d3mr7850271edi.331.1645186897584; Fri, 18 Feb 2022 04:21:37 -0800 (PST) Received: from orion.localdomain ([93.99.228.15]) by smtp.gmail.com with ESMTPSA id 1sm2270586ejm.173.2022.02.18.04.21.35 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 18 Feb 2022 04:21:35 -0800 (PST) Received: by orion.localdomain (Postfix, from userid 1003) id 435F3A7FF0; Fri, 18 Feb 2022 13:20:44 +0100 (CET) From: =?UTF-8?q?Jakub=20Mat=C4=9Bna?= To: linux-mm@kvack.org Cc: patches@lists.linux.dev, linux-kernel@vger.kernel.org, vbabka@suse.cz, mhocko@kernel.org, mgorman@techsingularity.net, willy@infradead.org, liam.howlett@oracle.com, hughd@google.com, kirill@shutemov.name, riel@surriel.com, rostedt@goodmis.org, peterz@infradead.org, =?UTF-8?q?Jakub=20Mat=C4=9Bna?= Subject: [RFC PATCH 1/4] [PATCH 1/4] mm: refactor of vma_merge() Date: Fri, 18 Feb 2022 13:20:16 +0100 Message-Id: <20220218122019.130274-2-matenajakub@gmail.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220218122019.130274-1-matenajakub@gmail.com> References: <20220218122019.130274-1-matenajakub@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-Rspam-User: Authentication-Results: imf10.hostedemail.com; dkim=pass header.d=gmail.com header.s=20210112 header.b=CcKCLBaP; spf=pass (imf10.hostedemail.com: domain of matenajakub@gmail.com designates 209.85.208.52 as permitted sender) smtp.mailfrom=matenajakub@gmail.com; dmarc=pass (policy=none) header.from=gmail.com X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: B2247C0002 X-Stat-Signature: f3qb3xz8tk96oaxzf4kjcb5yguuky4j1 X-HE-Tag: 1645186898-823585 Content-Transfer-Encoding: quoted-printable X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Refactor vma_merge() to make it shorter, more understandable and suitable for tracing of successful merges made possible by following patches in the series. Signed-off-by: Jakub Mat=C4=9Bna --- mm/mmap.c | 81 +++++++++++++++++++++++++++---------------------------- 1 file changed, 39 insertions(+), 42 deletions(-) diff --git a/mm/mmap.c b/mm/mmap.c index 1e8fdb0b51ed..b55e11f20571 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -1172,6 +1172,9 @@ struct vm_area_struct *vma_merge(struct mm_struct *= mm, pgoff_t pglen =3D (end - addr) >> PAGE_SHIFT; struct vm_area_struct *area, *next; int err; + int merge_prev =3D 0; + int merge_both =3D 0; + int merge_next =3D 0; =20 /* * We later require that vma->vm_flags =3D=3D vm_flags, @@ -1191,65 +1194,59 @@ struct vm_area_struct *vma_merge(struct mm_struct= *mm, VM_WARN_ON(addr >=3D end); =20 /* - * Can it merge with the predecessor? + * Can we merge predecessor? */ if (prev && prev->vm_end =3D=3D 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 =3D=3D 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 =3D __vma_adjust(prev, prev->vm_start, - next->vm_end, prev->vm_pgoff, NULL, - prev); - } else /* cases 2, 5, 7 */ - err =3D __vma_adjust(prev, prev->vm_start, - end, prev->vm_pgoff, NULL, prev); - if (err) - return NULL; - khugepaged_enter_vma_merge(prev, vm_flags); - return prev; + merge_prev =3D true; } - /* - * Can this new request be merged in front of next? + * Can we merge successor? */ if (next && end =3D=3D 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)) { + anon_vma, file, pgoff+pglen, + vm_userfaultfd_ctx, anon_name)) { + merge_next =3D true; + } + /* + * Can we merge both predecessor and successor? + */ + if (merge_prev && merge_next) + merge_both =3D is_mergeable_anon_vma(prev->anon_vma, next->anon_vma, N= ULL); + + if (merge_both) { /* cases 1, 6 */ + err =3D __vma_adjust(prev, prev->vm_start, + next->vm_end, prev->vm_pgoff, NULL, + prev); + area =3D prev; + } else if (merge_prev) { /* cases 2, 5, 7 */ + err =3D __vma_adjust(prev, prev->vm_start, + end, prev->vm_pgoff, NULL, prev); + area =3D prev; + } else if (merge_next) { if (prev && addr < prev->vm_end) /* case 4 */ err =3D __vma_adjust(prev, prev->vm_start, - addr, prev->vm_pgoff, NULL, next); - else { /* cases 3, 8 */ + addr, prev->vm_pgoff, NULL, next); + else /* cases 3, 8 */ err =3D __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 =3D next; - } - if (err) - return NULL; - khugepaged_enter_vma_merge(area, vm_flags); - return area; + next->vm_pgoff - pglen, NULL, next); + area =3D next; + } else { + err =3D -1; } =20 - return NULL; + /* + * Cannot merge with predecessor or successor or error in __vma_adjust? + */ + if (err) + return NULL; + khugepaged_enter_vma_merge(area, vm_flags); + return area; } =20 /* --=20 2.34.1