From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 51DB430DD10; Thu, 16 Jul 2026 08:21:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784190075; cv=none; b=C2puRXR7PL/gB/jZq03qcQ/LPm9wWTiiaVqOVYRPX6oZzw+qeCE1sl12RyndF9OxR/H38OjJpV2wiFdaiL+/Fuylgi2qHAp8Ju4+quyxx8bOlk8tn5iztY8DuYfbq6NJxVUa/E4rp2tICxIyca/AO4TYvjrtB0DjX7bHP7lsFRE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784190075; c=relaxed/simple; bh=u9wKlX7HZtVfoT2a/pM57RBeVSB/hMiOGSutkGW9v8s=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=JEOmFPywly3oB6d/H1D91EK3ITTYSUrYhJggMjcyD+R6wMs18onZSwKik89k3HqywKMXP3+HV7ewNIQIg0zOsRfEJvqOYAjBenAYtxy4JblXNxX+oCiF8WlDouX24YAmg+WjiIIit169+ouFrH5+c5/9ZkEypiDhbgDYv8VPIm8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=EcJ1ZExC; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="EcJ1ZExC" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 014761F000E9; Thu, 16 Jul 2026 08:20:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1784190073; bh=KnjMIDCod9I0T4C//k43rf+YCepYxv+BR7uQHADw3nM=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=EcJ1ZExC6m6pFPSJ/GG3vVVPZ64xO+OlYabJaaQKG5S7lh3gT1vt+DUvJUebMwTfi iHpC+PV0e0pfdrrfUF3G9pCCswqwpgHRVQuAVi0JkD6UZo2SqC2Ms9C0eVz34EtCMp l2gmisCD6iG4u9cyvaQN1mt+rL+u1760LL/z7akRpfIMhF7/rfw/kGHExaQdHrzwMH 3aR5vubkjamQnnYJfaoIugUobtSLRf9txOSM8HCufOU7LtSEwwRWCwath3cEHrdus3 j+oI9yNAqjQUR4Bi3BCRHSWAruUUs/RVWo/iRiLiZb8Y80NukuB6o/l1w8TaNIruHC Raqet4KRSwOfQ== Message-ID: <8c7240a2-59c6-4c56-8a29-14be272fc1d9@kernel.org> Date: Thu, 16 Jul 2026 10:20:50 +0200 Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 27/33] mm/vma: update vmg_adjust_set_range() to offset pgoff instead Content-Language: en-US To: Lorenzo Stoakes , Andrew Morton , David Hildenbrand , "Liam R. Howlett" , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Rik van Riel , Harry Yoo , Jann Horn , Lance Yang , Pedro Falcato , Russell King , Dinh Nguyen , Simon Schuster , "James E.J. Bottomley" , Helge Deller , Alexander Viro , Christian Brauner , Jan Kara , Dan Williams , Matthew Wilcox , Muchun Song , Oscar Salvador , Masami Hiramatsu , Oleg Nesterov , Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Namhyung Kim , Mark Rutland , Alexander Shishkin , Jiri Olsa , Ian Rogers , Adrian Hunter , James Clark , Zi Yan , Baolin Wang , Nico Pache , Ryan Roberts , Dev Jain , Barry Song , Miaohe Lin , Naoya Horiguchi , Xu Xin , Chengming Zhou , SJ Park , Matthew Brost , Joshua Hahn , Rakie Kim , Byungchul Park , Gregory Price , Ying Huang , Alistair Popple , Hugh Dickins , Peter Xu , Kees Cook , Marek Szyprowski , Robin Murphy , Andrey Konovalov , Alexander Potapenko , Dmitry Vyukov , Steven Rostedt , Mathieu Desnoyers , Jarkko Sakkinen , Dave Hansen , Thomas Gleixner , Borislav Petkov , x86@kernel.org, "H. Peter Anvin" , Ian Abbott , H Hartley Sweeten , Lucas Stach , Christian Gmeiner , David Airlie , Simona Vetter , Patrik Jakobsson , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , Rob Clark , Dmitry Baryshkov , Abhinav Kumar , Jessica Zhang , Sean Paul , Marijn Suijten , Tomi Valkeinen , Thierry Reding , Mikko Perttunen , Jonathan Hunter , Christian Koenig , Huang Rui , Matthew Auld , Jason Gunthorpe , Yishai Hadas , Shameer Kolothum , Kevin Tian , Ankit Agrawal , Alex Williamson , Paolo Bonzini , Shakeel Butt , Usama Arif Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-parisc@vger.kernel.org, linux-fsdevel@vger.kernel.org, nvdimm@lists.linux.dev, linux-perf-users@vger.kernel.org, linux-trace-kernel@vger.kernel.org, damon@lists.linux.dev, iommu@lists.linux.dev, kasan-dev@googlegroups.com, linux-sgx@vger.kernel.org, etnaviv@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-arm-msm@vger.kernel.org, freedreno@lists.freedesktop.org, linux-tegra@vger.kernel.org, kvm@vger.kernel.org, Russell King References: <20260710-b4-pre-scalable-cow-v2-0-2a5aa403d977@kernel.org> <20260710-b4-pre-scalable-cow-v2-27-2a5aa403d977@kernel.org> From: "Vlastimil Babka (SUSE)" Autocrypt: addr=vbabka@kernel.org; keydata= xsFNBFZdmxYBEADsw/SiUSjB0dM+vSh95UkgcHjzEVBlby/Fg+g42O7LAEkCYXi/vvq31JTB KxRWDHX0R2tgpFDXHnzZcQywawu8eSq0LxzxFNYMvtB7sV1pxYwej2qx9B75qW2plBs+7+YB 87tMFA+u+L4Z5xAzIimfLD5EKC56kJ1CsXlM8S/LHcmdD9Ctkn3trYDNnat0eoAcfPIP2OZ+ 9oe9IF/R28zmh0ifLXyJQQz5ofdj4bPf8ecEW0rhcqHfTD8k4yK0xxt3xW+6Exqp9n9bydiy tcSAw/TahjW6yrA+6JhSBv1v2tIm+itQc073zjSX8OFL51qQVzRFr7H2UQG33lw2QrvHRXqD Ot7ViKam7v0Ho9wEWiQOOZlHItOOXFphWb2yq3nzrKe45oWoSgkxKb97MVsQ+q2SYjJRBBH4 8qKhphADYxkIP6yut/eaj9ImvRUZZRi0DTc8xfnvHGTjKbJzC2xpFcY0DQbZzuwsIZ8OPJCc LM4S7mT25NE5kUTG/TKQCk922vRdGVMoLA7dIQrgXnRXtyT61sg8PG4wcfOnuWf8577aXP1x 6mzw3/jh3F+oSBHb/GcLC7mvWreJifUL2gEdssGfXhGWBo6zLS3qhgtwjay0Jl+kza1lo+Cv BB2T79D4WGdDuVa4eOrQ02TxqGN7G0Biz5ZLRSFzQSQwLn8fbwARAQABzSNWbGFzdGltaWwg QmFia2EgPHZiYWJrYUBrZXJuZWwub3JnPsLBsAQTAQoAWhYhBKlA1DSZLC6OmRA9UCJPp+fM gqZkBQJqFFy6GxSAAAAAAAQADm1hbnUyLDIuNSsxLjEyLDIsMgIbAwUJGtCBUAULCQgHAwUV CgkICwUWAgMBAAIeBQIXgAAKCRAiT6fnzIKmZJIUEADFx/tREzUImHrEwVHeSvDFmA7tJysI UVrlvrM09E7GIuzphzv7jYmo8n3ANpCczLEVr4G0syYQdTigaZgv3+FQDIIzhKih1IHhu1Ei XHlywNWKnQxxQEUNi5Mwx43wQz5XVw9F1A7gtKBKNtfogO511hAbrzagrYajyQacEJ/+sfhZ 9Da8ltHIXD8pcYaHUfQgEusCgmEd9+KrUwrTbckFKmYq5chuE6yJ4J0EmWknL096jIE6CnzF FRslQ3B1UKDjxVsm1ZHfir5NeWszLkTvGFsddFaWTgh8UycESG6VQzKXjjewXu2pG7YQYRpj QKm1W5X2TkwWkXRBZTmfmbhxIUMh3+zf5wQ463rSmDN/8v81tdqBtAW6rH/kzg1GvkaTHXn0 507yEHFzBksk2viAuIxxr7km8+/KARYLIdGtx30EG8cKzAUZOK6WqxtNCsXUJNrVE8CWrCaD icoNu7Fs1c5hmPHdSTnU48ce67449DdnO4neLSNhRiGlMHJgfJUmgrxu/hcYeOZ3haWmEQ2w uW1Mh01OHi8QZHCEyAbABrPs9GUgccc/4eYXX9hIgxfSkYzn8f+8NuIFPWl/0uTvjgqU29FQ SbzOLxHq9439Ox40G5mS5eZXRGxITYR+6TXvRGI6P/264jvflnr/pDGUttaikU+0W+1uxgKH cmYbEc7ATQRbGTU1AQgAn0H6UrFiWcovkh6EXVcl+SeqyO6JHOPm+e9Wu0Vw+VIUvXZVUVVQ La1PQDUi6j00ChlcR66g9/V0sPIcSutacPKfdKYOBvzd4rlhL8rfrdEsQw5ApZxrA8kYZVMh FmBRKAa6wos25moTlMKpCWzTH84+WO5+ziCTsTUZASAToz3RdunTD+vQcHj0GqNTPAHK63sf bAB2I0BslZkXkY1RLb/YhuA6E7JyEd2pilZOrIuBGl/5q2qSakgnAVFWFBR/DO27JuAksYnq +aH8vI0xGvwn75KqSk4UzAkDzWSmO4ZHuahKtQgZNsMYV+PGayRBX9b9zbldzopoLBdqHc4n jQARAQABwsF8BBgBCgAmAhsMFiEEqUDUNJksLo6ZED1QIk+n58yCpmQFAmfIHFQFCRYU6J8A CgkQIk+n58yCpmS2PA//bqN1LfcotmArgElsa+0EGZSQlYgK48pm8WAeTXTngudP9IJ4SuKY HR5RNjHcBeqN+Me0zxRqYzRb8nGanHEkDyf4Im8DQM8d6vbyU+FcPmG4skud4kgS1zMHnlVd SXfSIwKC/hKgdHG8aBV7545Lz9X6Iohea+94wneD0aw/hqF+QWewGZhWJriWAZtvEkzNjQOi 4U9F/trLten/x7bpphDSnDMKJtITbtzATT1Dq7o7VpIUK1nCTQALMuMjKCdi8OdU/+V+R3O4 0PXWvX8qrvqYapVbZ+9KqT74FsuB0Ya9uXwgBF2Q6cRuETZk5vqaqKxzqoQZCO8AOz/58j6O 2RHNy/mZEN+7tJ5Tsq42zVJ4jxsT8b9YplavCMsnBgDeRWhcbYhCyttoL7nYISyWg4kQYZ/P wIV3OuNv2f8iKYsxNsRuClOAF82+gvqOy1/1pprFjy8uo2pkoOrb63aOP3vO5VHnRKgra6dq NcaZ+c6J4H+nEJGi2SkHAUJz5oBzuThvPudLvPA/SK8sKoM01IRxSihev/S/5WLazXB1PGem OCbvzC1IjWJJraxiDJ5IygokapUa2RP7+WBR22skQ3SSl6G107QgWKSyTOGWEaRmV53vxQLV jXuCmzSSasTL60zq5yGrT4/DYQVSNEUiUbG4pYekxJujNeEDkUlky0Y= In-Reply-To: <20260710-b4-pre-scalable-cow-v2-27-2a5aa403d977@kernel.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 7/10/26 22:17, Lorenzo Stoakes wrote: > We are calculating the pgoff as an offset, since we have vma_add_pgoff() > and vma_sub_pgoff() available, just offset this value directly and use > __vma_set_range() for vma->vm_[start, end] values. > > We take care to update the range before offsetting the page offset, so the > adjusted VMA's vm_start and vm_pgoff are mutually consistent at the point > the page offset helpers operate - this matters once vma_set_pgoff() comes > to assert invariants which relate the two. > > Doing so lays the foundation for future work which allows for use of > virtual page offsets for MAP_PRIVATE-file backed mappings. > > No functional change intended. > > Reviewed-by: Pedro Falcato > Reviewed-by: Gregory Price > Signed-off-by: Lorenzo Stoakes Reviewed-by: Vlastimil Babka (SUSE) > --- > mm/vma.c | 15 ++++----------- > 1 file changed, 4 insertions(+), 11 deletions(-) > > diff --git a/mm/vma.c b/mm/vma.c > index a474920a25b3..0699fa07c40f 100644 > --- a/mm/vma.c > +++ b/mm/vma.c > @@ -714,9 +714,6 @@ void validate_mm(struct mm_struct *mm) > */ > static void vmg_adjust_set_range(struct vma_merge_struct *vmg) > { > - struct vm_area_struct *adjust; > - pgoff_t pgoff; > - > if (vmg->__adjust_middle_start) { > /* > * vmg->start vmg->end > @@ -735,8 +732,8 @@ static void vmg_adjust_set_range(struct vma_merge_struct *vmg) > struct vm_area_struct *middle = vmg->middle; > const unsigned long delta = vmg->end - middle->vm_start; > > - pgoff = vma_start_pgoff(middle) + (delta >> PAGE_SHIFT); > - adjust = middle; > + __vma_set_range(middle, vmg->end, middle->vm_end); > + vma_add_pgoff(middle, delta >> PAGE_SHIFT); > } else if (vmg->__adjust_next_start) { > /* > * Originally: > @@ -764,13 +761,9 @@ static void vmg_adjust_set_range(struct vma_merge_struct *vmg) > struct vm_area_struct *next = vmg->next; > const unsigned long delta = next->vm_start - vmg->end; > > - pgoff = vma_start_pgoff(next) - (delta >> PAGE_SHIFT); > - adjust = next; > - } else { > - return; > + __vma_set_range(next, vmg->end, next->vm_end); > + vma_sub_pgoff(next, delta >> PAGE_SHIFT); > } > - > - vma_set_range(adjust, vmg->end, adjust->vm_end, pgoff); > } > > /* >