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 C010B3451BB; Mon, 13 Jul 2026 18:12:47 +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=1783966369; cv=none; b=FHNB8bgUoetSUYdAuTDkIutYIT4ZzzraaLTVe4HSvuK1BKpWnr9LiToUH3bke/sg7/7ujsA0GIlH0dL+dZa2A62f8p/ncr8ib9t06spKTtp1N40L1AHVCTmmiZ7HPXIZIbWyNnz3yLVw0QSAL2M2RQlel94yZG0iIcegHEEua1U= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783966369; c=relaxed/simple; bh=I/4fHXq1nDSi0cCslAjghXGykmiUHd90ANku81Cd3+E=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=LTFtANqAdRFlIh+NYPUw36txDP1QUv0rMgvRw0WbaapuElGSTxTnZbFmxoT2v6/PsarCkz2GekYoTORiU5b9/qW0Yje7wKotAKBiVbvCxUTyr3rBqbF2mhVdY0YvPna2ZqqKmol1kozPMwRPgOoVV9WTwTezZHtU85hutbwLNMQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=L+dTcR3m; 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="L+dTcR3m" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8B9981F000E9; Mon, 13 Jul 2026 18:12:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1783966367; bh=Vz1aumqsT0b6f336r0aYehoTvpo8WfxfycSLqp4UaWQ=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=L+dTcR3mLBKUAyeuAPNAmmTZgYLKhxdgRU7fgk/CZX8rtGYQHFGBNuvzOHW+8J5/N h4Y5NyOqrJywCWN9KORJieMrGlECHA/FzhDVGIyzGPq0wR/M+2BuPs1Si3NFpqzTU1 rOHidmcl6Qi22RveSlyjiOik4B5o4h5U1iC+01HSJFgW61QY3qQcUvpN8L0SuwFp7W XIQ/6rsy80spgSBLHqHEBJxKscfwj/07cV5k7TYTLba+ujWjsvrAvfMAhFckm8sEUq v+n5RpW267LaUqUkTF4I8gnuoL2knURw0tFUL0aTBulsMqD5AWu/KxIKZOkuYOUNbi BNiYAZXuIRDTQ== Message-ID: <508301c5-5460-40e8-bc34-6410be5be40a@kernel.org> Date: Mon, 13 Jul 2026 20:12:24 +0200 Precedence: bulk X-Mailing-List: linux-perf-users@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 13/33] mm/vma: introduce and use vmg_pages(), vmg_[start, end]_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-v2-13-2a5aa403d977@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-v2-13-2a5aa403d977@kernel.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 7/10/26 22:16, Lorenzo Stoakes wrote: > In the VMA logic we often need to determine the number of pages in the > specified merge range, as well as the start and end page offsets of that > range. > > Introduce and use helpers for these purposes. > > No functional change intended. > > Reviewed-by: Pedro Falcato > Reviewed-by: Gregory Price > Signed-off-by: Lorenzo Stoakes Uh, the PHYS_PFN() usage here was quite an abuse. Good riddance. Reviewed-by: Vlastimil Babka (SUSE) > --- > mm/vma.c | 11 ++++------- > mm/vma.h | 17 +++++++++++++++++ > 2 files changed, 21 insertions(+), 7 deletions(-) > > diff --git a/mm/vma.c b/mm/vma.c > index 35ba3475128f..995de8198fbb 100644 > --- a/mm/vma.c > +++ b/mm/vma.c > @@ -197,11 +197,9 @@ static void init_multi_vma_prep(struct vma_prepare *vp, > */ > static bool can_vma_merge_before(struct vma_merge_struct *vmg) > { > - pgoff_t pglen = PHYS_PFN(vmg->end - vmg->start); > - > if (is_mergeable_vma(vmg, /* merge_next = */ true) && > is_mergeable_anon_vma(vmg, /* merge_next = */ true)) { > - if (vmg->next->vm_pgoff == vmg->pgoff + pglen) > + if (vmg_end_pgoff(vmg) == vma_start_pgoff(vmg->next)) > return true; > } > > @@ -221,7 +219,7 @@ static bool can_vma_merge_after(struct vma_merge_struct *vmg) > { > if (is_mergeable_vma(vmg, /* merge_next = */ false) && > is_mergeable_anon_vma(vmg, /* merge_next = */ false)) { > - if (vmg->prev->vm_pgoff + vma_pages(vmg->prev) == vmg->pgoff) > + if (vma_end_pgoff(vmg->prev) == vmg_start_pgoff(vmg)) > return true; > } > return false; > @@ -759,7 +757,7 @@ static int commit_merge(struct vma_merge_struct *vmg) > */ > vma_adjust_trans_huge(vma, vmg->start, vmg->end, > vmg->__adjust_middle_start ? vmg->middle : NULL); > - vma_set_range(vma, vmg->start, vmg->end, vmg->pgoff); > + vma_set_range(vma, vmg->start, vmg->end, vmg_start_pgoff(vmg)); > vmg_adjust_set_range(vmg); > vma_iter_store_overwrite(vmg->vmi, vmg->target); > > @@ -962,8 +960,7 @@ static __must_check struct vm_area_struct *vma_merge_existing_range( > * middle next > * shrink/delete extend > */ > - > - pgoff_t pglen = PHYS_PFN(vmg->end - vmg->start); > + const pgoff_t pglen = vmg_pages(vmg); > > VM_WARN_ON_VMG(!merge_right, vmg); > /* If we are offset into a VMA, then prev must be middle. */ > diff --git a/mm/vma.h b/mm/vma.h > index 8e4b61a7304c..527716c8739d 100644 > --- a/mm/vma.h > +++ b/mm/vma.h > @@ -230,6 +230,23 @@ static inline bool vmg_nomem(struct vma_merge_struct *vmg) > return vmg->state == VMA_MERGE_ERROR_NOMEM; > } > > +static inline pgoff_t vmg_start_pgoff(const struct vma_merge_struct *vmg) > +{ > + return vmg->pgoff; > +} > + > +static inline pgoff_t vmg_pages(const struct vma_merge_struct *vmg) > +{ > + const unsigned long size = vmg->end - vmg->start; > + > + return size >> PAGE_SHIFT; > +} > + > +static inline pgoff_t vmg_end_pgoff(const struct vma_merge_struct *vmg) > +{ > + return vmg_start_pgoff(vmg) + vmg_pages(vmg); > +} > + > /* Assumes addr >= vma->vm_start. */ > static inline pgoff_t vma_pgoff_offset(struct vm_area_struct *vma, > unsigned long addr) >