From: "Lorenzo Stoakes (ARM)" <ljs@kernel.org>
To: Gregory Price <gourry@gourry.net>
Cc: Andrew Morton <akpm@linux-foundation.org>,
David Hildenbrand <david@kernel.org>,
"Liam R. Howlett" <liam@infradead.org>,
Vlastimil Babka <vbabka@kernel.org>,
Mike Rapoport <rppt@kernel.org>,
Suren Baghdasaryan <surenb@google.com>,
Michal Hocko <mhocko@suse.com>, Jann Horn <jannh@google.com>,
Pedro Falcato <pfalcato@suse.de>,
"Matthew Wilcox (Oracle)" <willy@infradead.org>,
Jan Kara <jack@suse.cz>, Miaohe Lin <linmiaohe@huawei.com>,
Naoya Horiguchi <nao.horiguchi@gmail.com>,
Rik van Riel <riel@surriel.com>, Harry Yoo <harry@kernel.org>,
Lance Yang <lance.yang@linux.dev>, Kees Cook <kees@kernel.org>,
Zi Yan <ziy@nvidia.com>,
Baolin Wang <baolin.wang@linux.alibaba.com>,
Nico Pache <npache@redhat.com>,
Ryan Roberts <ryan.roberts@arm.com>, Dev Jain <dev.jain@arm.com>,
Barry Song <baohua@kernel.org>,
Usama Arif <usama.arif@linux.dev>,
Matthew Brost <matthew.brost@intel.com>,
Joshua Hahn <joshua.hahnjy@gmail.com>,
Rakie Kim <rakie.kim@sk.com>, Byungchul Park <byungchul@sk.com>,
Ying Huang <ying.huang@linux.alibaba.com>,
Alistair Popple <apopple@nvidia.com>,
Peter Xu <peterx@redhat.com>, Xu Xin <xu.xin16@zte.com.cn>,
Chengming Zhou <chengming.zhou@linux.dev>,
Arnd Bergmann <arnd@arndb.de>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
linux-fsdevel@vger.kernel.org, linux-kselftest@vger.kernel.org
Subject: Re: [PATCH v2 01/15] mm/vma: introduce VMA virtual page offset field and add helpers
Date: Mon, 27 Jul 2026 13:03:38 +0100 [thread overview]
Message-ID: <amdJEz-Sl8LRB_5l@lucifer> (raw)
In-Reply-To: <al5ZPYH-0T6IPXox@gourry-fedora-PF4VCD3F>
On Mon, Jul 20, 2026 at 01:26:09PM -0400, Gregory Price wrote:
> On Mon, Jul 20, 2026 at 05:56:52PM +0100, Lorenzo Stoakes (ARM) wrote:
> > On Mon, Jul 20, 2026 at 11:49:00AM -0400, Gregory Price wrote:
> > > On Mon, Jul 20, 2026 at 03:38:27PM +0100, Lorenzo Stoakes (ARM) wrote:
> > > >
> > > > The virtual page offset of a VMA is equal to vma->vm_start >> PAGE_SHIFT if
> > > > they are unfaulted or were not remapped, otherwise it is equal to this
> > > > value at the point of first fault.
> > > >
> > >
> > > The latter half of this description is a bit confusing.
> > >
> > > Why would the value differ from (vma->vm_start >> PAGE_SHIFT)?
> > > (because it's file backed?
> >
> > Because the VMA gets remapped.
> >
> > If it's remapped when it's unfaulted, then virtual page offset gets updated, if
> > it's faulted then not.
> >
>
> ahhhhh the wording is just wonky then
>
> when faulted or remapped, x is...
> when unfaulted or unremapped, x is...
>
> instead of
>
> x is ... if unfaulted or were not remapped, otherwise...
>
> Sort of a complex combination of 3 negatives there.
>
> ~Gregory
>
Ack, will improve wording!
Cheers, Lorenzo
next prev parent reply other threads:[~2026-07-27 12:04 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-07-20 14:38 [PATCH v2 00/15] mm/rmap: index MAP_PRIVATE file-backed folios by virt pgoff Lorenzo Stoakes (ARM)
2026-07-20 14:38 ` [PATCH v2 01/15] mm/vma: introduce VMA virtual page offset field and add helpers Lorenzo Stoakes (ARM)
2026-07-20 15:49 ` Gregory Price
2026-07-20 16:56 ` Lorenzo Stoakes (ARM)
2026-07-20 17:26 ` Gregory Price
2026-07-27 12:03 ` Lorenzo Stoakes (ARM) [this message]
2026-07-25 8:08 ` xu.xin16
2026-07-20 14:38 ` [PATCH v2 02/15] mm: introduce linear_virt_page_index() Lorenzo Stoakes (ARM)
2026-07-20 14:38 ` [PATCH v2 03/15] mm: abstract vma_address() and introduce vma_anon_address() Lorenzo Stoakes (ARM)
2026-07-20 14:38 ` [PATCH v2 04/15] mm: update print_bad_page_map() to show virtual page index Lorenzo Stoakes (ARM)
2026-07-20 14:38 ` [PATCH v2 05/15] mm: introduce and use vma_filebacked_address() Lorenzo Stoakes (ARM)
2026-07-20 14:38 ` [PATCH v2 06/15] mm: propagate VMA virtual page offset on map, remap, split + merge Lorenzo Stoakes (ARM)
2026-07-20 14:38 ` [PATCH v2 07/15] mm/rmap: track whether the page VMA mapped walk is anonymous Lorenzo Stoakes (ARM)
2026-07-20 14:38 ` [PATCH v2 08/15] mm: introduce and use linear_folio_page_index() Lorenzo Stoakes (ARM)
2026-07-20 14:38 ` [PATCH v2 09/15] mm/rmap: use virt pgoff for MAP_PRIVATE file-backed anon folios Lorenzo Stoakes (ARM)
2026-07-20 14:38 ` [PATCH v2 10/15] tools/testing/vma: expand VMA merge tests to assert virt pgoff Lorenzo Stoakes (ARM)
2026-07-20 14:38 ` [PATCH v2 11/15] tools/testing/selftests/mm: test virtual page offset merge behaviour Lorenzo Stoakes (ARM)
2026-07-20 14:38 ` [PATCH v2 12/15] mm/vma: only permit MAP_PRIVATE /dev/zero to be mapped anonymous Lorenzo Stoakes (ARM)
2026-07-20 14:38 ` [PATCH v2 13/15] mm/vma: make MAP_PRIVATE-mapped /dev/zero mappings truly anonymous Lorenzo Stoakes (ARM)
2026-07-27 11:48 ` Mark Brown
2026-07-27 12:03 ` Lorenzo Stoakes (ARM)
2026-07-20 14:38 ` [PATCH v2 14/15] tools/testing/vma: add test to assert MAP_PRIVATE-/dev/zero is anon Lorenzo Stoakes (ARM)
2026-07-20 14:38 ` [PATCH v2 15/15] tools/testing/selftests/mm: add MAP_PRIVATE-/dev/zero merge tests Lorenzo Stoakes (ARM)
2026-07-20 19:48 ` [PATCH v2 00/15] mm/rmap: index MAP_PRIVATE file-backed folios by virt pgoff Andrew Morton
2026-07-27 12:04 ` Lorenzo Stoakes (ARM)
2026-07-27 14:44 ` David Hildenbrand (Arm)
2026-07-27 15:57 ` Lorenzo Stoakes (ARM)
2026-07-27 15:59 ` Matthew Wilcox
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