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 3163A494A0C; Wed, 15 Jul 2026 17:39:02 +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=1784137144; cv=none; b=osR2YY/I6wZ8nu1ylHyjeDu2H0hn59tb7ebmFkCYI3U+Q6FbMGm4YcSABTCeOLrC138gySDvacR/3OiAeSFUpzPR6TX6OZmTMTVMtaAmlrdt+vZ/2Ck1oQC0NUJJEBpUVMrrN2rKbDJLgj6IwlUHnVePzYYnDxibiM3c8BQLrFw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784137144; c=relaxed/simple; bh=HD81DZSyxG7U5KGoxsfk5NbaP1azSVtMJ6idr3025J0=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=PetBerEMwL7Bt2B5Vp9ClnasfxCnZgNRSgE4gUsIXoGqtc7H/9nzfiM4VzfBTTwQHn7R7yHycC0X4ZbAhUKsJ2oT2n3zE8rBNV+eZv+5bt8o+cUVD/+PbHQiT7cLllwQzTLOqxUgjEl0Zw6QAfz3SCN67O0H9z4CUtUgjSLL2R0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=H+l4Gk5g; 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="H+l4Gk5g" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E342B1F000E9; Wed, 15 Jul 2026 17:38:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1784137142; bh=FIVkPfvxeJwmFsRzcsFULZGgDP6nk/t1TXi4jFC/9ps=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=H+l4Gk5gMH0FmUaSgBbfUPPpEpu/cj1Doq8pMoy/Tdh/nysr2VPDoTBkxZqSlqjKf Jmr36Iuk83frIZqFUemo0sFrNNDyrM9rQZV9vhmKsJ0j/swnTjVsf0mxRD/XbZD1Ux QwVMKB+0NqfThWqItxcHlWnQLBH+bVu4njeC5WPpUpK7CCi0GEESuHNILJMIlF7IOW 2PxhotQ3zR1S+GjK3EUCMcRRWhyoithUpbnpXUpzyyoCcbEKbnnpjFOFAuyfprRnzd j67UClRU4OTWC/PzZAkL0kxXCsSxET+OTjnmu9WYYlbAJ+0W8eAySESShGyplCR3T3 o6vl7tIqtmMhg== Message-ID: Date: Wed, 15 Jul 2026 19:38:38 +0200 Precedence: bulk X-Mailing-List: linux-sgx@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 23/33] mm/vma: add and use vma_[add/sub]_pgoff() 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-v2-23-2a5aa403d977@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-v2-23-2a5aa403d977@kernel.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 7/10/26 22:17, Lorenzo Stoakes wrote: > Add helpers for adding or subtracting to a VMA's page offset, exposed > internally for VMA users within mm in mm/vma.h. > > This is to lay the foundations for tracking anonymous page offset for > MAP_PRIVATE file-backed mappings, where adding and subtracting from this > value must be reflected in both the file and anonymous offsets. > > These are used on VMA split and downward stack expansion. > > No functional change intended. > > Reviewed-by: Pedro Falcato > Signed-off-by: Lorenzo Stoakes Reviewed-by: Vlastimil Babka (SUSE) Nits: > --- > mm/nommu.c | 6 ++++-- > mm/vma.c | 6 +++--- > mm/vma.h | 12 ++++++++++++ > 3 files changed, 19 insertions(+), 5 deletions(-) > > diff --git a/mm/nommu.c b/mm/nommu.c > index c0a0869cd0d6..2a0136f6081d 100644 > --- a/mm/nommu.c > +++ b/mm/nommu.c > @@ -41,6 +41,7 @@ > #include > #include > #include "internal.h" > +#include "vma.h" > > unsigned long highest_memmap_pfn; > int heap_stack_gap = 0; > @@ -1361,7 +1362,8 @@ static int split_vma(struct vma_iterator *vmi, struct vm_area_struct *vma, > region->vm_top = region->vm_end = new->vm_end = addr; > } else { > region->vm_start = new->vm_start = addr; > - region->vm_pgoff = new->vm_pgoff += npages; Ah that takes care of the other case of ugliness I noticed earlier, good. > + vma_add_pgoff(new, npages); > + region->vm_pgoff = vma_start_pgoff(new); > } > > vma_iter_config(vmi, new->vm_start, new->vm_end); > @@ -1378,7 +1380,7 @@ 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_pgoff += npages; > + vma_add_pgoff(vma, npages); > vma->vm_region->vm_pgoff = vma_start_pgoff(vma); > } else { > vma->vm_region->vm_end = vma->vm_end = addr; > diff --git a/mm/vma.c b/mm/vma.c > index 7aa0149f076c..bdd99ba56b4d 100644 > --- a/mm/vma.c > +++ b/mm/vma.c > @@ -517,7 +517,7 @@ __split_vma(struct vma_iterator *vmi, struct vm_area_struct *vma, > new->vm_end = addr; > } else { > new->vm_start = addr; > - new->vm_pgoff += linear_page_delta(vma, addr); > + vma_add_pgoff(new, linear_page_delta(vma, addr)); > } > > err = -ENOMEM; > @@ -556,7 +556,7 @@ __split_vma(struct vma_iterator *vmi, struct vm_area_struct *vma, > > if (new_below) { > vma->vm_start = addr; > - vma->vm_pgoff += (addr - new->vm_start) >> PAGE_SHIFT; > + vma_add_pgoff(vma, (addr - new->vm_start) >> PAGE_SHIFT); Hm isn't this also a case for using linear_page_delta(addr, new)? (I guess in patch 21/33) Would be like the hunk above. > } else { > vma->vm_end = addr; > } > @@ -3305,7 +3305,7 @@ int expand_downwards(struct vm_area_struct *vma, unsigned long address) > vm_stat_account(mm, vma->vm_flags, grow); > anon_rmap_tree_pre_update_vma(vma); > vma->vm_start = address; > - vma->vm_pgoff -= grow; > + vma_sub_pgoff(vma, grow); > /* Overwrite old entry in mtree. */ > vma_iter_store_overwrite(&vmi, vma); > anon_rmap_tree_post_update_vma(vma); > diff --git a/mm/vma.h b/mm/vma.h > index 2342516ce00e..47fe35e5307e 100644 > --- a/mm/vma.h > +++ b/mm/vma.h > @@ -247,6 +247,18 @@ static inline pgoff_t vmg_end_pgoff(const struct vma_merge_struct *vmg) > return vmg_start_pgoff(vmg) + vmg_pages(vmg); > } > > +static inline void vma_add_pgoff(struct vm_area_struct *vma, pgoff_t delta) > +{ > + vma_assert_can_modify(vma); > + vma->vm_pgoff += delta; > +} > + > +static inline void vma_sub_pgoff(struct vm_area_struct *vma, pgoff_t delta) > +{ > + vma_assert_can_modify(vma); > + vma->vm_pgoff -= delta; > +} > + > #define VMG_STATE(name, mm_, vmi_, start_, end_, vma_flags_, pgoff_) \ > struct vma_merge_struct name = { \ > .mm = mm_, \ >