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 1EFB840EBA9; Wed, 15 Jul 2026 15:23:33 +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=1784129015; cv=none; b=TFN+bKZjvz00aq1X+GcCrPdWiTitVGmPD7/mig7wgFepy6DUvO/YcOPky9lTS7Q2ESfIcibCXl4Uc+YFo0DIX7xejCOqGtTHLlA3MWSezX14qeGHnfq3OluZVyAW6DLT3lWfyb27yiOhlFtK/glexQLlMtRaQeytJH54U0NjPk8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784129015; c=relaxed/simple; bh=9qP5LTAAk44gQZWTOXHoo7e15j4FHHXFk9sg8XT9+0Q=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=u03MzYz3xa6h66jCcaIBK9vHWA9H6o0xbd/kAtalWra2u7LemVbnTirWdid7nFS1XTcmsOlVrnfI3W6JxRF5m9ZRMtKvzmG12/3ni2gYR+KmTFtk/PoENoruO1cdNaOczfrjfSur2Q1b3zvx00M27orqs83+Zdwl5EoU6TfuW2w= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=ZHFyZ3/E; 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="ZHFyZ3/E" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 75C0D1F000E9; Wed, 15 Jul 2026 15:23:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1784129013; bh=gADdUqFqdyogeafk3zRAASxcmVNA8sWMqOF6K7MzJug=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=ZHFyZ3/ESAlbGMLodf52X6TrDO35Fk0c445fZjc/iDIOmZR8ceLOBcpqvIoraEE/T zeZLVqqi8htF9IPg8x+JFm/Ztq0YO7W22l91dvkihGZ/j+CaDbNRZ39M+h2IRRAPJn gOwM6i12c2CphR2jeaPmOSZdn2QRqByY6vZbMn4L22uOeN5KpZu94g9LE+GSWDYy6a desBFAJqgZSmmDqsf6sL7guf2TNq50pwPkhffsRmu0Wzj0YQUUSEp7cTuNMhMWtN9x FtkNO+2bfvmhwRnIK4YG/8FPR+l9FBnCEYqbL8I9dQIXx97pCo7on9ZfnrfGoOLbdP TCsIyKOC40Lgg== Message-ID: Date: Wed, 15 Jul 2026 17:23:09 +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 18/33] mm/vma: use vma_start_pgoff(), linear_page_index() in mm code 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-arm-kernel@lists.infradead.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-v2-18-2a5aa403d977@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-v2-18-2a5aa403d977@kernel.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 7/10/26 22:16, Lorenzo Stoakes wrote: > There are many instances in which linear_page_index() (as well as > linear_page_delta()) is open-coded, which is confusing and inconsistent. > > Additionally, vma->vm_pgoff doesn't necessarily make it clear that this is > the page offset of the start of the VMA range. > > Doing so also aids greppability. > > So use vma_start_pgoff() in favour of directly accessing vma->vm_pgoff, and > linear_page_index() where we can. > > This also lays the ground for future changes which will add an anonymous > page offset in order to be able to index MAP_PRIVATE-file backed anon > folios in terms of their virtual page offset. > > No functional change intended. > > Reviewed-by: Gregory Price > Reviewed-by: SJ Park > Reviewed-by: Pedro Falcato > Signed-off-by: Lorenzo Stoakes Reviewed-by: Vlastimil Babka (SUSE) Nit: > diff --git a/mm/damon/vaddr.c b/mm/damon/vaddr.c > index 2058db9c01d5..d10b8042adb5 100644 > --- a/mm/damon/vaddr.c > +++ b/mm/damon/vaddr.c > @@ -10,6 +10,7 @@ > #include > #include > #include > +#include > #include > #include > > @@ -623,8 +624,8 @@ static void damos_va_migrate_dests_add(struct folio *folio, > } > > order = folio_order(folio); > - ilx = vma->vm_pgoff >> order; > - ilx += (addr - vma->vm_start) >> (PAGE_SHIFT + order); > + ilx = vma_start_pgoff(vma) >> order; > + ilx += linear_page_delta(vma, addr) >> order; Could these be combined to linear_page_index(vma, addr) >> order? > > for (i = 0; i < dests->nr_dests; i++) > weight_total += dests->weight_arr[i]; > diff --git a/mm/filemap.c b/mm/filemap.c > index b39111abdc4b..1dbb4c6f824e 100644 > --- a/mm/filemap.c > +++ b/mm/filemap.c > @@ -3411,8 +3411,8 @@ static struct file *do_sync_mmap_readahead(struct vm_fault *vmf) > * of memory. > */ > struct vm_area_struct *vma = vmf->vma; > - unsigned long start = vma->vm_pgoff; > - unsigned long end = start + vma_pages(vma); > + const unsigned long start = vma_start_pgoff(vma); > + const unsigned long end = vma_end_pgoff(vma); > unsigned long ra_end; > > ra->order = exec_folio_order(); > @@ -3930,7 +3930,8 @@ vm_fault_t filemap_map_pages(struct vm_fault *vmf, > goto out; > } > > - addr = vma->vm_start + ((start_pgoff - vma->vm_pgoff) << PAGE_SHIFT); > + addr = vma->vm_start + > + ((start_pgoff - vma_start_pgoff(vma)) << PAGE_SHIFT); This could be linear_page_index(vma, start_pgoff) << > vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, addr, &vmf->ptl); > if (!vmf->pte) { > folio_unlock(folio); > --- a/mm/mempolicy.c > +++ b/mm/mempolicy.c > @@ -2049,8 +2049,8 @@ struct mempolicy *get_vma_policy(struct vm_area_struct *vma, > pol = get_task_policy(current); > if (pol->mode == MPOL_INTERLEAVE || > pol->mode == MPOL_WEIGHTED_INTERLEAVE) { > - *ilx += vma->vm_pgoff >> order; > - *ilx += (addr - vma->vm_start) >> (PAGE_SHIFT + order); > + *ilx += vma_start_pgoff(vma) >> order; > + *ilx += linear_page_delta(vma, addr) >> order; Also? > } > return pol; > } > --- a/mm/nommu.c > +++ b/mm/nommu.c > @@ -975,7 +975,7 @@ static int do_mmap_private(struct vm_area_struct *vma, > /* read the contents of a file into the copy */ > loff_t fpos; > > - fpos = vma->vm_pgoff; > + fpos = vma_start_pgoff(vma); > fpos <<= PAGE_SHIFT; > > ret = kernel_read(vma->vm_file, base, len, &fpos); > @@ -1378,7 +1378,8 @@ static int split_vma(struct vma_iterator *vmi, struct vm_area_struct *vma, > delete_nommu_region(vma->vm_region); > if (new_below) { > vma->vm_region->vm_start = vma->vm_start = addr; > - vma->vm_region->vm_pgoff = vma->vm_pgoff += npages; yuck, good to remove that ugly construct it's not the only occurence in this function oh well > + vma->vm_pgoff += npages; > + vma->vm_region->vm_pgoff = vma_start_pgoff(vma); > } else { > vma->vm_region->vm_end = vma->vm_end = addr; > vma->vm_region->vm_top = addr;