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 3B3EA3644CF; Tue, 14 Jul 2026 10:17:47 +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=1784024268; cv=none; b=KoARJtzUTnXChmf2Ufmh6BWVO6FMgt/WqrkkainQ9/6YkXo72jB14UASOGPznSGKiNKf08VcP09hEZCQXvPVuTF5gZQKaIYMWMn0Fd2fmP63+SPTkE+54Rg5bmIWrpKrjKMLQTR5FfOtdrPgVhhJkLvWSOpUIxWQMiM/y2seVFc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784024268; c=relaxed/simple; bh=4DH5a6ve/auP/7V1bjyB0V4QG2dck0UzPWpYqC6/K2k=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=gLcLeuk+BDUCgI/Utnn9318eE4ks4juatKBtAsY3GwsxdDJJIB9hXvBcw29WAMPdf0cMeZ/V9I45Joos8rwZ9/pQiT2fRKXgox9poFtuzrL+1YB0g85Pt/QWBmivN9agjPbS8XPa+vaIaW6HuPUPUfJgVdQaKE/EsD0EEfaOEmk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Fy6x3ScG; 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="Fy6x3ScG" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9C4FE1F00A3A; Tue, 14 Jul 2026 10:17:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1784024267; bh=m1KwIxFOjH59vMqkPqvNJy2V0MLfN207LfncRH5TxDo=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=Fy6x3ScGp4SvjcLCb2EYasEF7Bg+N3JfXA1S2rYhDdGa8fr4+6eT9Z5sUIb80sT2r 12V6KN+91XeSPeyZyRfBCNnMtsE0Z3zX1AfM0d9+BaPvnE/m8+pkUwQTaWwez7DEAX 40QuoDzKqfzY1GCwuoG58CjBJE29XwBLRxM4TLNdmwQj8Blhck0AkxR92okiojzvMx WvMiVcF3zrA3KFpoksv9rfWx4gssKNluZWhtd5duC3QeTgeKUloBSHGktJzF0RJITM VrXH2ihLGQi0Xivwew6+5RuBX85r1ZYghiUkt5mTAu6e5JRNfb657XTWVfzpRGcHfX 762G6nWtq/nvw== Date: Tue, 14 Jul 2026 11:17:11 +0100 From: "Lorenzo Stoakes (ARM)" To: "Vlastimil Babka (SUSE)" Cc: 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 , 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 Subject: Re: [PATCH v2 13/33] mm/vma: introduce and use vmg_pages(), vmg_[start, end]_pgoff() Message-ID: References: <20260710-b4-pre-scalable-cow-v2-0-2a5aa403d977@kernel.org> <20260710-b4-pre-scalable-cow-v2-13-2a5aa403d977@kernel.org> <508301c5-5460-40e8-bc34-6410be5be40a@kernel.org> Precedence: bulk X-Mailing-List: linux-perf-users@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <508301c5-5460-40e8-bc34-6410be5be40a@kernel.org> On Mon, Jul 13, 2026 at 08:12:24PM +0200, Vlastimil Babka (SUSE) wrote: > 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. Yeah and mine :)) but absolutely agree it was wrong and glad to fix my own mistake in using that ;) > Reviewed-by: Vlastimil Babka (SUSE) Thanks! > > > --- > > 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) > > > Cheers, Lorenzo