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23285 Commits

Author SHA1 Message Date
Warren Xiong
8bc69b8d20 selftests/mm: read memory information without popen 
read_memory_info() invokes two shell pipelines to obtain MemFree and
Hugepagesize from /proc/meminfo.  It does not check whether popen()
returns NULL before passing the result to fgets(), and it does not call
pclose() when fgets() fails.

Open /proc/meminfo directly and obtain both values in a single pass.  This
removes the unchecked NULL path, closes the file on all paths, and avoids
dependencies on external commands.

The compaction test continues to pass after this change.

Link: https://lore.kernel.org/1785845818-3131-1-git-send-email-warren.xiong@ugreen.com
Signed-off-by: Warren Xiong <warren.xiong@ugreen.com>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-08-24 18:43:01 -07:00
Pratyush Mallick
4e7e499b75 selftests/mm: rename local_config.h to local_config.h_gen 
Patch series "selftests/mm: use pattern matching in .gitignore", v4.

The current selftests/mm/.gitignore hardcodes each generated test binary
by name, which requires manual updates every time a new test is added.

This series switches to a pattern-matching approach (similar to KVM
selftests), ignoring everything by default and allowing specific source
extensions.  To accommodate this without tracking generated headers,
local_config.h is renamed to local_config.h_gen.


This patch (of 2):

Because local_config.h is a generated build artifact, un-ignoring all .h
files in .gitignore causes it to incorrectly show up as an untracked file
in git status.

Rename it to local_config.h_gen so it no longer matches the !*.h inclusion
rule, preparing for a subsequent patch that switches .gitignore to a
pattern-matching approach.

Update Makefile, check_config.sh, and affected test sources (cow.c,
gup_longterm.c) accordingly.

Link: https://lore.kernel.org/20260803221732.3651981-1-pratmal@google.com
Link: https://lore.kernel.org/20260803221732.3651981-2-pratmal@google.com
Signed-off-by: Pratyush Mallick <pratmal@google.com>
Reviewed-by: Lorenzo Stoakes <ljs@kernel.org>
Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Suggested-by: David Hildenbrand <david@kernel.org>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: "Liam R. Howlett" <liam@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Yosry Ahmed <yosry@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-08-24 18:43:01 -07:00
Lorenzo Stoakes (ARM)
fb580e1964 tools/testing/selftests/mm: test anonymous page offset merge behaviour 
While maintaining anonymous page offsets for VMAs has no impact for most
merge cases, it does impact MAP_PRIVATE-mapped file-backed mappings which
happen to have matching page offset but not matching anonymous page
offset.

Assert this behaviour by attempting to map an unfaulted MAP_PRIVATE-memfd
region with a faulted one with compatible file page offsets but
incompatible anonymous page offsets.

Link: https://lore.kernel.org/20260813-b4-scalable-cow-virt-pgoff-v5-16-c21581c0c3c8@kernel.org
Signed-off-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Deucher <alexander.deucher@amd.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Baoquan He <baoquan.he@linux.dev>
Cc: Barry Song <baohua@kernel.org>
Cc: Boris Brezillon <boris.brezillon@collabora.com>
Cc: Byungchul Park <byungchul@sk.com>
Cc: Chengming Zhou <chengming.zhou@linux.dev>
Cc: Chris Li <chrisl@kernel.org>
Cc: Christan König <christian.koenig@amd.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Claudio Imbrenda <imbrenda@linux.ibm.com>
Cc: Dave Airlie <airlied@gmail.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Gregory Price (Meta) <gourry@gourry.net>
Cc: Harry Yoo <harry@kernel.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Huang Ray <Ray.Huang@amd.com>
Cc: "Huang, Ying" <ying.huang@linux.alibaba.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@linaro.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Janosch Frank <frankja@linux.ibm.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Joshua Hahn <joshua.hahnjy@gmail.com>
Cc: Kairui Song <kasong@tencent.com>
Cc: Kees Cook <kees@kernel.org>
Cc: Kemeng Shi <shikemeng@huaweicloud.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Liviu Dudau <liviu.dudau@arm.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Marc Rutland <mark.rutland@arm.com>
Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
Cc: Matthew Auld <matthew.auld@intel.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Namhyung kim <namhyung@kernel.org>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Pedro Falcato <pfalcato@suse.de>
Cc: Peter Xu <peterx@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Steven Price <steven.price@arm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Thomas Zimemrmann <tzimmermann@suse.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: xu xin <xu.xin16@zte.com.cn>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-08-24 18:42:54 -07:00
Lorenzo Stoakes (ARM)
6b7460ad1a tools/testing/vma: expand VMA merge tests to assert anon pgoff 
Now we have introduced the VMA anonymous page offset attribute and update
it when VMAs are manipulated, update VMA merge tests to assert that the
anonymous page offset is as expected.

Also update instances where we could use vma_start_pgoff() to do so.

Link: https://lore.kernel.org/20260813-b4-scalable-cow-virt-pgoff-v5-15-c21581c0c3c8@kernel.org
Signed-off-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Deucher <alexander.deucher@amd.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Baoquan He <baoquan.he@linux.dev>
Cc: Barry Song <baohua@kernel.org>
Cc: Boris Brezillon <boris.brezillon@collabora.com>
Cc: Byungchul Park <byungchul@sk.com>
Cc: Chengming Zhou <chengming.zhou@linux.dev>
Cc: Chris Li <chrisl@kernel.org>
Cc: Christan König <christian.koenig@amd.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Claudio Imbrenda <imbrenda@linux.ibm.com>
Cc: Dave Airlie <airlied@gmail.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Gregory Price (Meta) <gourry@gourry.net>
Cc: Harry Yoo <harry@kernel.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Huang Ray <Ray.Huang@amd.com>
Cc: "Huang, Ying" <ying.huang@linux.alibaba.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@linaro.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Janosch Frank <frankja@linux.ibm.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Joshua Hahn <joshua.hahnjy@gmail.com>
Cc: Kairui Song <kasong@tencent.com>
Cc: Kees Cook <kees@kernel.org>
Cc: Kemeng Shi <shikemeng@huaweicloud.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Liviu Dudau <liviu.dudau@arm.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Marc Rutland <mark.rutland@arm.com>
Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
Cc: Matthew Auld <matthew.auld@intel.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Namhyung kim <namhyung@kernel.org>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Pedro Falcato <pfalcato@suse.de>
Cc: Peter Xu <peterx@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Steven Price <steven.price@arm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Thomas Zimemrmann <tzimmermann@suse.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: xu xin <xu.xin16@zte.com.cn>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-08-24 18:42:53 -07:00
Lorenzo Stoakes (ARM)
6a993c7fbc mm: propagate VMA anonymous page offset on map, remap, split + merge 
We must correctly update VMA anonymous page offset state on all VMA
operations that would result in it changing, with special attention given
to remapping.

We cover most cases by simply updating vma_set_range() to do so (with a
new anonymous page offset parameter), but also notably must update the
merging and mapping logic to propagate this parameter correctly.

The remap logic remains the same - we may update the anonymous page offset
if the VMA is unfaulted, but now this applies to MAP_PRIVATE file-backed
mappings too, so we update the code to reflect this.

Note that we use __linear_anon_page_index() upon remap as the VMA may be
shared, in order that we update the field consistently regardless of VMA
type.

Similarly, pass through anon page offset to the merge logic, updating the
vma_merge_struct struct to propagate it, and also use
__linear_anon_page_index() to obtain the anonymous page index so it can be
safely used for both shared and MAP_PRIVATE file-backed mappings.

In copy_vma(), the anonymous page offset is updated regardless of whether
the mapping is a CoW mapping or not.  This is both to keep the anonymous
page offset consistent even for non-CoW mappings (it is set so should at
least remain correct) and makes the logic cleaner.

A self-merge however remains permitted only for mappings which can have a
populated vma->anon_vma and do not require alignment on a separate file
offset - that is pure anonymous VMAs, so only set can_self_merge if
vma_is_anonymous().

Finally, we update insert_vm_struct() to correctly set the anonymous page
offset on insertion of a VMA.

We simply ensure state is correctly propagated here, so no functional
changes are intended.

Also update VMA userland tests to reflect this change.

Link: https://lore.kernel.org/20260813-b4-scalable-cow-virt-pgoff-v5-9-c21581c0c3c8@kernel.org
Signed-off-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Deucher <alexander.deucher@amd.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Baoquan He <baoquan.he@linux.dev>
Cc: Barry Song <baohua@kernel.org>
Cc: Boris Brezillon <boris.brezillon@collabora.com>
Cc: Byungchul Park <byungchul@sk.com>
Cc: Chengming Zhou <chengming.zhou@linux.dev>
Cc: Chris Li <chrisl@kernel.org>
Cc: Christan König <christian.koenig@amd.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Claudio Imbrenda <imbrenda@linux.ibm.com>
Cc: Dave Airlie <airlied@gmail.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Gregory Price (Meta) <gourry@gourry.net>
Cc: Harry Yoo <harry@kernel.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Huang Ray <Ray.Huang@amd.com>
Cc: "Huang, Ying" <ying.huang@linux.alibaba.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@linaro.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Janosch Frank <frankja@linux.ibm.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Joshua Hahn <joshua.hahnjy@gmail.com>
Cc: Kairui Song <kasong@tencent.com>
Cc: Kees Cook <kees@kernel.org>
Cc: Kemeng Shi <shikemeng@huaweicloud.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Liviu Dudau <liviu.dudau@arm.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Marc Rutland <mark.rutland@arm.com>
Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
Cc: Matthew Auld <matthew.auld@intel.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Namhyung kim <namhyung@kernel.org>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Pedro Falcato <pfalcato@suse.de>
Cc: Peter Xu <peterx@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Steven Price <steven.price@arm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Thomas Zimemrmann <tzimmermann@suse.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: xu xin <xu.xin16@zte.com.cn>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-08-24 18:42:52 -07:00
Lorenzo Stoakes (ARM)
746b9e0a47 tools/testing/vma: add tests for copy_vma() self-merge 
Assert that a VMA can be moved backwards, forwards and between a preceding
VMA and its old self.

In the cases in which the VMA merges only with itself expect that to be
achieved by expanding its old self, so assert that these function
correctly.

However in the case of a merge between a preceding VMA and itself the
original VMA is removed, so assert that the preceding VMA replaces the one
passed in as vmap and the merge is as expected.

Link: https://lore.kernel.org/20260813-b4-scalable-cow-virt-pgoff-v5-8-c21581c0c3c8@kernel.org
Signed-off-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Deucher <alexander.deucher@amd.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Baoquan He <baoquan.he@linux.dev>
Cc: Barry Song <baohua@kernel.org>
Cc: Boris Brezillon <boris.brezillon@collabora.com>
Cc: Byungchul Park <byungchul@sk.com>
Cc: Chengming Zhou <chengming.zhou@linux.dev>
Cc: Chris Li <chrisl@kernel.org>
Cc: Christan König <christian.koenig@amd.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Claudio Imbrenda <imbrenda@linux.ibm.com>
Cc: Dave Airlie <airlied@gmail.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Gregory Price (Meta) <gourry@gourry.net>
Cc: Harry Yoo <harry@kernel.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Huang Ray <Ray.Huang@amd.com>
Cc: "Huang, Ying" <ying.huang@linux.alibaba.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@linaro.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Janosch Frank <frankja@linux.ibm.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Joshua Hahn <joshua.hahnjy@gmail.com>
Cc: Kairui Song <kasong@tencent.com>
Cc: Kees Cook <kees@kernel.org>
Cc: Kemeng Shi <shikemeng@huaweicloud.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Liviu Dudau <liviu.dudau@arm.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Marc Rutland <mark.rutland@arm.com>
Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
Cc: Matthew Auld <matthew.auld@intel.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Namhyung kim <namhyung@kernel.org>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Pedro Falcato <pfalcato@suse.de>
Cc: Peter Xu <peterx@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Steven Price <steven.price@arm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Thomas Zimemrmann <tzimmermann@suse.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: xu xin <xu.xin16@zte.com.cn>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-08-24 18:42:51 -07:00
Lorenzo Stoakes (ARM)
9998bc06d7 mm/vma: fix self-merge check in copy_vma() 
The existing logic is very confusing so improve things.  Firstly rename
the confusing faulted_in_anon_vma variable to can_self_merge and update
this when the page offset is updated.

What is being checked for is a 'self-merge' - that is between the VMA
being remapped and its prior VMA (remember that this is copy_vma() - if a
non-MREMAP_DONTUNMAP remap the original VMA is only removed afterwards).

This can happen if the VMA is moved immediately adjacent to itself, either
before or after it:

		|----------------|----------------|
		|		 |                |
		v		 |		  v
	|...............||---------------||...............|
	|      new      ||      old      ||      new      |
	|...............||---------------||---------------|

In these cases the old VMA is simply expanded to cover the new range.

It is also possible for the move to both self-merge and merge with a prior
VMA if it is placed between a preceding VMA and its old self:

				|---------------|
				|		|
				v		|
	|---------------||...............||---------------|
	|      prev     ||     new       ||     old       |
	|---------------||...............||---------------|

In this case, the old VMA is removed and 'prev' is expanded and replaces
it.

Since copy_vma_and_data() which calls copy_vma() intends to reference the
old VMA after the merge, it must have this pointer updated.

This kind of self-merge is not possible with a succeeding merge, as the
merge always prefers to expand the preceding VMA if possible.

copy_vma() accounts for this by explicitly checking to see if a self-merge
occurred and updating the vmap pointer if so.  However it incorrect did so
even for a subsequent merge (this is simply a noop so it had no impact).

So change this to only check for the case which matters - a backwards
merge - and rearrange the parameters to make it clearer we're doing that -
i.e.  check new_vma->vm_start < old_vma_start (having already renamed
vma_start to old_vma_start to make it clear this is the previous VMA).

Also update the existing wall-of-text comment to be a lot clearer.

While we're here, replace the VM_BUG_ON_VMA() with a VM_WARN_ON_ONCE_VMA()
and update the VMA userland tests accordingly.

No functional change intended.

Link: https://lore.kernel.org/20260813-b4-scalable-cow-virt-pgoff-v5-7-c21581c0c3c8@kernel.org
Signed-off-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Deucher <alexander.deucher@amd.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Baoquan He <baoquan.he@linux.dev>
Cc: Barry Song <baohua@kernel.org>
Cc: Boris Brezillon <boris.brezillon@collabora.com>
Cc: Byungchul Park <byungchul@sk.com>
Cc: Chengming Zhou <chengming.zhou@linux.dev>
Cc: Chris Li <chrisl@kernel.org>
Cc: Christan König <christian.koenig@amd.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Claudio Imbrenda <imbrenda@linux.ibm.com>
Cc: Dave Airlie <airlied@gmail.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Gregory Price (Meta) <gourry@gourry.net>
Cc: Harry Yoo <harry@kernel.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Huang Ray <Ray.Huang@amd.com>
Cc: "Huang, Ying" <ying.huang@linux.alibaba.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@linaro.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Janosch Frank <frankja@linux.ibm.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Joshua Hahn <joshua.hahnjy@gmail.com>
Cc: Kairui Song <kasong@tencent.com>
Cc: Kees Cook <kees@kernel.org>
Cc: Kemeng Shi <shikemeng@huaweicloud.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Liviu Dudau <liviu.dudau@arm.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Marc Rutland <mark.rutland@arm.com>
Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
Cc: Matthew Auld <matthew.auld@intel.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Namhyung kim <namhyung@kernel.org>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Pedro Falcato <pfalcato@suse.de>
Cc: Peter Xu <peterx@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Steven Price <steven.price@arm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Thomas Zimemrmann <tzimmermann@suse.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: xu xin <xu.xin16@zte.com.cn>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-08-24 18:42:51 -07:00
Lorenzo Stoakes (ARM)
7e6543d1f9 mm: introduce linear_anon_page_index() 
This function provides the anonymous equivalent of linear_page_index(),
instead offsetting based on the anonymous page offset of the VMA.

It is valid only for anonymous or MAP_PRIVATE file-backed mappings, in
other words CoW mappings.

For pure anon VMAs, this will be equal to linear_page_index().

Assert that both of these invariants are true in linear_anon_page_index()
and implement the algorithm in __linear_anon_page_index().

Note that MAP_PRIVATE-/dev/zero mappings will satisfy vma_is_anonymous()
but not fulfill this invariant, so when asserting this we check
vma->vm_file to account for this.

We do not update callsites yet, so no functional change intended.

Also const-ify vma_is_anonymous() to make it compatible with the
const-ified linear_anon_page_index().

While we're here, update linear_page_index() to be more succinct.

VMA userland tests are also updated accordingly.

Link: https://lore.kernel.org/20260813-b4-scalable-cow-virt-pgoff-v5-3-c21581c0c3c8@kernel.org
Signed-off-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>
Reviewed-by: Gregory Price (Meta) <gourry@gourry.net>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Deucher <alexander.deucher@amd.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Baoquan He <baoquan.he@linux.dev>
Cc: Barry Song <baohua@kernel.org>
Cc: Boris Brezillon <boris.brezillon@collabora.com>
Cc: Byungchul Park <byungchul@sk.com>
Cc: Chengming Zhou <chengming.zhou@linux.dev>
Cc: Chris Li <chrisl@kernel.org>
Cc: Christan König <christian.koenig@amd.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Claudio Imbrenda <imbrenda@linux.ibm.com>
Cc: Dave Airlie <airlied@gmail.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Harry Yoo <harry@kernel.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Huang Ray <Ray.Huang@amd.com>
Cc: "Huang, Ying" <ying.huang@linux.alibaba.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@linaro.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Janosch Frank <frankja@linux.ibm.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Joshua Hahn <joshua.hahnjy@gmail.com>
Cc: Kairui Song <kasong@tencent.com>
Cc: Kees Cook <kees@kernel.org>
Cc: Kemeng Shi <shikemeng@huaweicloud.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Liviu Dudau <liviu.dudau@arm.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Marc Rutland <mark.rutland@arm.com>
Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
Cc: Matthew Auld <matthew.auld@intel.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Namhyung kim <namhyung@kernel.org>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Pedro Falcato <pfalcato@suse.de>
Cc: Peter Xu <peterx@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Steven Price <steven.price@arm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Thomas Zimemrmann <tzimmermann@suse.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: xu xin <xu.xin16@zte.com.cn>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-08-24 18:42:50 -07:00
Lorenzo Stoakes (ARM)
51943a18ad mm: provide vma_[flags_]is_cow_mapping() and remove is_cow_mapping() 
All remaining callers of is_cow_mapping() are invoking it in the form of
is_cow_mapping(vma->vm_flags) or an indirected version of this.

Therefore, provide a helper - vma_is_cow_mapping() to directly test the
VMA.

Additionally provide a new helper vma_flags_is_cow_mapping() which
performs the check using the new vma_flags_t type, and share this logic
between vma_is_cow_mapping() and vma_desc_is_cow_mapping().

With these changes, no callers of is_cow_mapping() remain, so remove it.

Also update the userland VMA tests to reflect the change.

No functional change intended.

[akpm@linux-foundation.org: fix kerneldoc comment typo, per Lorenzo]
  Link: https://lore.kernel.org/aob1goSSPH6sTN9y@gremlin
Link: https://lore.kernel.org/20260813-b4-scalable-cow-virt-pgoff-v5-2-c21581c0c3c8@kernel.org
Signed-off-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Deucher <alexander.deucher@amd.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Baoquan He <baoquan.he@linux.dev>
Cc: Barry Song <baohua@kernel.org>
Cc: Boris Brezillon <boris.brezillon@collabora.com>
Cc: Byungchul Park <byungchul@sk.com>
Cc: Chengming Zhou <chengming.zhou@linux.dev>
Cc: Chris Li <chrisl@kernel.org>
Cc: Christan König <christian.koenig@amd.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Claudio Imbrenda <imbrenda@linux.ibm.com>
Cc: Dave Airlie <airlied@gmail.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Gregory Price (Meta) <gourry@gourry.net>
Cc: Harry Yoo <harry@kernel.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Huang Ray <Ray.Huang@amd.com>
Cc: "Huang, Ying" <ying.huang@linux.alibaba.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@linaro.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Janosch Frank <frankja@linux.ibm.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Joshua Hahn <joshua.hahnjy@gmail.com>
Cc: Kairui Song <kasong@tencent.com>
Cc: Kees Cook <kees@kernel.org>
Cc: Kemeng Shi <shikemeng@huaweicloud.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Liviu Dudau <liviu.dudau@arm.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Marc Rutland <mark.rutland@arm.com>
Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
Cc: Matthew Auld <matthew.auld@intel.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Namhyung kim <namhyung@kernel.org>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Pedro Falcato <pfalcato@suse.de>
Cc: Peter Xu <peterx@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Steven Price <steven.price@arm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Thomas Zimemrmann <tzimmermann@suse.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: xu xin <xu.xin16@zte.com.cn>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-08-24 18:42:50 -07:00
Lorenzo Stoakes (ARM)
0bd14001eb mm/vma: introduce VMA anon page offset field and add helpers 
Patch series "mm/rmap: index MAP_PRIVATE file-backed folios by anonymous
pgoff", v5.

In memory management we've managed to manufacture a great deal of
confusion around the concept of anonymous memory.  We have:

1. 'Pure anon' memory - anonymous VMAs whose folios are anonymous and
   swap-backed (thus for reclaim purposes, treated as anonymous). These are
   simple enough.

2. shmem - file-backed VMAs, file-backed folios (from rmap perspective) so
   present in the page cache and mapped by an address_space object, but
   whose folios are also swap-backed (thus treated as anonymous for reclaim
   purposes).

3. MAP_PRIVATE-mapped /dev/zero - a strange beast whose VMAs have
   vma->vm_file set, but which clears vma->vm_ops to satisfy
   vma_is_anonymous(), resulting in VMAs that were mmap()'d referencing a
   file, but are in every other sense anonymous, including the folios.

4. Other MAP_PRIVATE-file backed mappings - These possess file-backed VMAs
   and have file-backed folios until CoW'd, at which point those CoW'd
   folios are anonymous.

This series fixes issue 3.

In order for us to traverse VMAs using the reverse mapping, we require two
fields - folio->mapping and folio->index.  The first tells the rmap code
where to look for VMAs, and the second tells it at which offset the folio
starts within the referenced object.

For anonymous folios, folio->mapping points at an anon_vma object.  For
file-backed folios, it points at an address_space.  And:

* For file-backed folios folio->index is simply the page offset of the start
  of the folio within the file.

* For anonymous folios belonging to pure anon mappings, folio->index is
  equal to the anonymous page offset of the folio.

* For anonymous folios belonging to file-backed mappings (i.e. CoW'd folios
  of a MAP_PRIVATE file-backed mapping), folio->index is equal to the file
  page offset.

This series establishes a new anonymous page offset property of VMAs to
allow us to map anonymous folios at their anonymous page offset,
consistent with pure anon.

The purpose of doing so is to lay the foundations for the scalable CoW
work.  This is necessary because scalable CoW looks in the maple tree for
the VMA located at folio->index << PAGE_SHIFT, before falling back to
looking up tracked remaps if necessary.

The MAP_PRIVATE file-backed case means that folio indices will very often
conflict with one another and this remap tracking becomes substantially
more contended, and of course the fast path can never be used.

This also makes it possible, in future, to unshare anonymously mapped
folios with deep fork hierarchies on remap, eliminating the need for remap
tracking in the vast majority of cases.

Similar to page offset of pure anonymous VMAs, we update the anonymous
page offset of unfaulted file-backed VMAs on remap, but do not once CoW'd
(i.e.  vma->anon_vma is non-NULL).

Overall, there is little impact on mergeability, which remains exactly the
same for pure anonymous and shared file-backed mappings, with the only
impact being on MAP_PRIVATE-mapped file-backed mappings, which must now
match on anonymous page offset as well as file page offset to be merged.

To fail to merge like this would require CoW'ing the mapping, then finding
another VMA with identical file and compatible page offset to remap next
to.

This is therefore very much an edge case that should have very little
impact (and which scalable CoW may very well address in any case).


This patch (of 16):

Establish fields in vm_area_struct to store the anonymous page offset of
VMAs.

Initially, the anonymous page offset of a VMA is vma->vm_start >>
PAGE_SHIFT.

When a VMA is remapped to new_address its anonymous page offset is either
updated to new_address >> PAGE_SHIFT if unfaulted or, if faulted, remains
equal to the anonymous page offset it had when first faulted.

Currently, anonymous folios belonging to CoW'd MAP_PRIVATE-mapped
file-backed VMAs are tracked by their file offsets.  By adding anonymous
offset as a property of VMAs, we can now track them by their anonymous
page offset instead.

By tracking this, we provide the means by which to eliminate this
inconsistency, and more importantly lay the foundations for future work
for the scalable CoW anonymous rmap rework.

This patch simply adds the fields and some simple helpers.  Subsequent
patches will update mm code to make use of these fields correctly.

The fields chosen are packed in the VMA such that, for 64-bit kernel
builds, no additional space is taken up.

The first field is present on cacheline 0 containing key VMA fields, and
the second on cacheline 3, which contains file-backed reverse mapping
fields.

Given the relative time spent accessing reverse mapping fields as well as
updating them, there shouldn't be any performance impact here from false
sharing.

Update the VMA userland tests to account for this change.

No callsites are updated yet, so no functional change intended.

Link: https://lore.kernel.org/20260813-b4-scalable-cow-virt-pgoff-v5-0-c21581c0c3c8@kernel.org
Link: https://lore.kernel.org/20260813-b4-scalable-cow-virt-pgoff-v5-1-c21581c0c3c8@kernel.org
Signed-off-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Reviewed-by: Gregory Price (Meta) <gourry@gourry.net>
Reviewed-by: Xu Xin <xu.xin16@zte.com.cn>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Deucher <alexander.deucher@amd.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Baoquan He <baoquan.he@linux.dev>
Cc: Barry Song <baohua@kernel.org>
Cc: Boris Brezillon <boris.brezillon@collabora.com>
Cc: Byungchul Park <byungchul@sk.com>
Cc: Chengming Zhou <chengming.zhou@linux.dev>
Cc: Chris Li <chrisl@kernel.org>
Cc: Christan König <christian.koenig@amd.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Claudio Imbrenda <imbrenda@linux.ibm.com>
Cc: Dave Airlie <airlied@gmail.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Harry Yoo <harry@kernel.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Huang Ray <Ray.Huang@amd.com>
Cc: "Huang, Ying" <ying.huang@linux.alibaba.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@linaro.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Janosch Frank <frankja@linux.ibm.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Joshua Hahn <joshua.hahnjy@gmail.com>
Cc: Kairui Song <kasong@tencent.com>
Cc: Kees Cook <kees@kernel.org>
Cc: Kemeng Shi <shikemeng@huaweicloud.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Liviu Dudau <liviu.dudau@arm.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Marc Rutland <mark.rutland@arm.com>
Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
Cc: Matthew Auld <matthew.auld@intel.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Namhyung kim <namhyung@kernel.org>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Pedro Falcato <pfalcato@suse.de>
Cc: Peter Xu <peterx@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Steven Price <steven.price@arm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Thomas Zimemrmann <tzimmermann@suse.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: xu xin <xu.xin16@zte.com.cn>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-08-24 18:42:49 -07:00
Mike Rapoport (Microsoft)
08745c6235 selftests/mm: thuge-gen: fix test_shmget() for PAGE_SIZE check 
Commit 49a4e7186b ("selftests/mm: thuge-gen: add setup of HugeTLB
pages") changed thuge-gen test to use common functions for reading hugetlb
attributes from sysfs, but it missed that the original read_free()
function special cased PAGE_SIZE tests.

For PAGE_SIZE tests, failure to read sysfs was ignored and read_free()
returned 0.

This allowed test_shmget() to essentially skip the check of how many huge
pages was consumed when it ran with PAGE_SIZE.

Commit 3199b0c09efa ("selftests/mm: fix read_file() return value check")
fixed checks for read_file() return value and this exposed the issue in
test_shmget() that checks the number of free hugetlb pages even for
PAGE_SIZE test, tries to access

/sys/kernel/mm/hugepages/hugepages-<PAGE_SIZE>/free_hugepages

and obviously fails there.

Gate the checks for free huge pages on size != getpagesize() and
initialize before and after variables to values matching PAGE_SIZE test.

Link: https://lore.kernel.org/20260812-selftests-thuge-gen-fix-v2-1-9adaa693e73b@kernel.org
Fixes: 49a4e7186b ("selftests/mm: thuge-gen: add setup of HugeTLB pages")
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Reviewed-by: Sarthak Sharma <sarthak.sharma@arm.com>
Acked-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-08-15 21:12:24 -07:00
Muhammad Usama Anjum
288058d8db selftests/mm: unpoison pages in memory-failure teardown 
The memory-failure tests call cleanup() only after all result checks.  A
failed ASSERT_* invokes fixture teardown and aborts the test, so it skips
cleanup() and leaves the injected page hardware-poisoned.

Invoke cleanup() from FIXTURE_TEARDOWN() instead.  Guard it with
self->injection_attempted so tests that exit before injection do not try
to unpoison a page when no injection was attempted.  Injection can poison
a page before returning an error or delivering SIGBUS, so teardown must
clean up after every injection attempt.  This runs the existing HWPoison
and HardwareCorrupted checks on both normal and assertion-failure paths.

Link: https://lore.kernel.org/20260729091127.1001179-1-usama.anjum@arm.com
Fixes: ff4ef2fbd1 ("selftests/mm: add memory failure anonymous page test")
Signed-off-by: Muhammad Usama Anjum <usama.anjum@arm.com>
Reviewed-by: David Hildenbrand (Arm) <david@kernel.org>
Acked-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-08-06 18:57:27 -07:00
zhaozhengzhuo
5716a333c9 selftests/mm: fix gup_longterm EINVAL error message 
The gup_longterm test prints a literal "n" when PIN_LONGTERM_TEST_START
fails with EINVAL because the string is missing the newline escape
sequence.

Print a newline instead.

Link: https://lore.kernel.org/23557F4CB8CF36FF+20260724074603.1479243-1-zhaozhengzhuo@uniontech.com
Signed-off-by: zhaozhengzhuo <zhaozhengzhuo@uniontech.com>
Reviewed-by: Sarthak Sharma <sarthak.sharma@arm.com>
Reviewed-by: Dev Jain <dev.jain@arm.com>
Acked-by: David Hildenbrand (arm) <david@kernel.org>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-08-06 18:57:24 -07:00
longlong yan
9922d4ced6 selftests/mm/pagemap_ioctl: fix missing NULL checks after calloc() 
The pagemap_ioctl selftest allocates memory via calloc() in several places
but does not check the return values.  If calloc() fails, the subsequent
code will dereference a NULL pointer and crash.

Additionally, in sanity_tests(), the calloc() failure check incorrectly
uses MAP_FAILED (the mmap() error constant) instead of NULL.  Since
calloc() returns NULL on failure, the check never triggers and a failed
allocation goes undetected.

Add NULL checks after each calloc() call, and fix the wrong error constant
in sanity_tests().  Use ksft_exit_fail_msg() consistent with the existing
error handling pattern in the file.

Link: https://lore.kernel.org/20260721063611.342-1-yanlonglong@kylinos.cn
Signed-off-by: longlong yan <yanlonglong@kylinos.cn>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Reviewed-by: SJ Park <sj@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-08-06 18:57:21 -07:00
longlong yan
63b4209482 selftests/mm: use MAP_FAILED for mmap error check 
Replace the direct comparison with (void *)-1 with the standard MAP_FAILED
macro when checking mmap()

Link: https://lore.kernel.org/20260720063439.522-1-yanlonglong@kylinos.cn
Signed-off-by: longlong yan <yanlonglong@kylinos.cn>
Reviewed-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-08-06 18:57:21 -07:00
Hongfu Li
1605ce99af selftests/mm: fix BUG_ON checking wrong variable in mremap_dontunmap 
In mremap_dontunmap_partial_mapping_overwrite(), mremap() stores its
returned remapped address into remapped_mapping, while the BUG_ON
incorrectly checks dest_mapping instead.

If mremap() fails, dest_mapping still holds a valid pointer obtained from
the prior mmap() call, making this BUG_ON never trigger at all.  Correct
the check to validate the actual mremap() return value stored in
remapped_mapping.

Link: https://lore.kernel.org/20260717070251.73212-1-hongfu.li@linux.dev
Signed-off-by: Hongfu Li <lihongfu@kylinos.cn>
Reviewed-by: SJ Park <sj@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-08-06 18:57:14 -07:00
Kiryl Shutsemau (Meta)
fb0493ad1a selftests/mm: add PAGEMAP_SCAN test for THP PMD holes 
Add coverage for the PMD-hole case fixed by "fs/proc/task_mmu: fix
PAGEMAP_SCAN written state for PMD holes": a MAP_PRIVATE|MAP_ANON THP that
is uffd-wp'd and then dropped with MADV_DONTNEED leaves a pmd_none hole
with no page table, which PAGEMAP_SCAN must still report as written.

Factor the populate/drop/scan-both-paths sequence out of
unpopulated_scan_test() into a helper, and add unpopulated_thp_scan_test()
that reuses it with a THP.

Include <linux/mman.h> for MADV_COLLAPSE; <sys/mman.h> lacks it on older
glibc (e.g. 2.34). Same approach as commit fd5295afae ("selftests/mm:
hmm-tests: include linux/mman.h to access MADV_COLLAPSE").

Link: https://lore.kernel.org/aljWYfPRCVc6IB2b@thinkstation
Link: https://lore.kernel.org/20260715144234.442721-3-kirill@shutemov.name
Signed-off-by: Kiryl Shutsemau <kas@kernel.org>
Cc: Muhammad Usama Anjum <usama.anjum@arm.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Zenghui Yu <zenghui.yu@linux.dev>
Cc: David Hildenbrand <david@kernel.org>
Cc: Jann Horn <jannh@google.com>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Pedro Falcato <pfalcato@suse.de>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Assisted-by: Claude:claude-fable-5
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-08-06 18:57:10 -07:00
Lorenzo Stoakes
8e7501a361 mm/vma: update create_init_stack_vma() to use vma_flags_t 
Replace use of the legacy vm_flags_t flags with vma_flags_t values in
create_init_stack_vma().

As part of this change we add VMA_STACK_EARLY and VMA_STACK_INCOMPLETE
vma_flags_t defines, and slightly rework create_init_stack_vma() for
clarity.

No functional change intended.

Link: https://lore.kernel.org/20260711-b4-vma-flags-mm-v2-9-0fa2357d5431@kernel.org
Signed-off-by: Lorenzo Stoakes <ljs@kernel.org>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Lance Yang <lance.yang@linux.dev>
Reviewed-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Dave Airlie <airlied@gmail.com>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Nico Pache <npache@redhat.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Pedro Falcato <pfalcato@suse.de>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-08-06 18:57:03 -07:00
Lorenzo Stoakes
a2fdfd0080 mm: introduce vma_get_page_prot() and use it 
There's a large number of vm_get_page_prot(vma->vm_flags) invocations. 
Make life easier by introducing vma_get_page_prot() parameterised by the
VMA.

This also makes converting vm_get_page_prot() to vma_flags_t easier.

Also update the userland VMA tests to reflect the change.

No functional change intended.

Link: https://lore.kernel.org/20260711-b4-vma-flags-mm-v2-8-0fa2357d5431@kernel.org
Signed-off-by: Lorenzo Stoakes <ljs@kernel.org>
Acked-by: Zi Yan <ziy@nvidia.com>
Acked-by: Jani Nikula <jani.nikula@intel.com> # for i915
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>	[DRM]
Reviewed-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Dave Airlie <airlied@gmail.com>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Nico Pache <npache@redhat.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Pedro Falcato <pfalcato@suse.de>
Cc: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-08-06 18:57:03 -07:00
Lorenzo Stoakes
e28266b033 mm/vma: rename vma_get_page_prot to vma_flags_to_page_prot 
Having vma_get_page_prot() refer to VMA flags and vma_set_page_prot()
refer to a VMA is confusing.

Rename vma_get_page_prot() to vma_flags_to_page_prot() to resolve this
confusion.

No functional change intended.

Link: https://lore.kernel.org/20260711-b4-vma-flags-mm-v2-7-0fa2357d5431@kernel.org
Signed-off-by: Lorenzo Stoakes <ljs@kernel.org>
Reviewed-by: Lance Yang <lance.yang@linux.dev>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Dave Airlie <airlied@gmail.com>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Nico Pache <npache@redhat.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Pedro Falcato <pfalcato@suse.de>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-08-06 18:57:02 -07:00
Gregory Price
249c5ee21a selftests/dax: add dax/kmem hotplug sysfs regression test 
Add a kselftest for the dax/kmem whole-device "state" sysfs attribute
(/sys/bus/dax/devices/daxX.Y/state), which transitions a kmem-backed
dax device between "unplugged", "online" and "online_movable".

The kselftest also includes a test to demonstrate the force-unbind
does not deadlock - but this is destructive (the dax device can never
be rebound), so it only runs when DAX_KMEM_TEST_UNBIND=1 is set.

Provisioning a devdax device and binding it to kmem needs daxctl/ndctl
out of scope for an in-tree selftest.  As the test mutates a device's
memory, the operator opts in by naming it in DAX_KMEM_TEST_DEV (or
"auto" to pick the first kmem-bound device); it SKIPs when unset, when
no device is present, or when the memory cannot be freed to a baseline.

When a device is available it validates the interface contract:
  - online / online_movable actually add memory (MemTotal grows),
  - online is idempotent,
  - switching between online types without unplug is rejected,
  - unplug removes memory and the reported state is "unplugged"
  - invalid input is rejected,
  - unplug and unbind tolerate blocks toggled out-of-band through the
    per-block memoryX/state interface.

One specific regression test:
    online -> unplug -> online_movable -> unplug

Re-online must re-reserve per-range resources so subsequent unplug
actually offlines and removes instead of silently reporting success
while the memory stays online.

Link: https://lore.kernel.org/20260712154505.3564379-11-gourry@gourry.net
Signed-off-by: Gregory Price <gourry@gourry.net>
Cc: Alison Schofield <alison.schofield@intel.com>
Cc: Danilo Krummrich <dakr@kernel.org>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: David Hildenbrand (Arm) <david@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Pankaj Gupta <pankaj.gupta@amd.com>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-08-06 18:57:00 -07:00
Hongfu Li
824d80962c selftests/mm: factor out hmm_buffer_alloc() to consolidate buffer setup 
Each HMM test open-codes the same buffer initialization sequence: allocate
main buffer, assign file descriptor and size, allocate mirror buffer, then
perform mmap mapping.  Factor out this repeated logic into a standalone
hmm_buffer_alloc() helper to eliminate ~35 open-coded copies.

The new helper supports distinct mmap_size and mirror_size parameters to
fit scenarios with THP alignment padding or per-page snapshot flags.  It
also exposes prot, flags and fd arguments, enabling support for
MAP_SHARED, MAP_HUGETLB and file-backed mappings.

Eliminates ~360 lines of redundant boilerplate code.  Fixes a missing NULL
pointer check bug in the hmm_buffer_alloc() previously used only by the
migration benchmark, now subsumed by this new unified helper.

Link: https://lore.kernel.org/20260713033209.280435-1-lihongfu@kylinos.cn
Signed-off-by: Hongfu Li <lihongfu@kylinos.cn>
Cc: David Hildenbrand <david@kernel.org>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-08-06 18:56:56 -07:00
Injae Ryou
98df164036 selftests/mm: fix on-fault-limit false failure under sudo-rs 
run_vmtests.sh runs on-fault-limit as the nobody user via "sudo -u nobody
./on-fault-limit", guarded by a check that nobody can access the binary
("sudo -u nobody ls ./on-fault-limit").

The guard resolves the relative path from the inherited working directory,
which only requires search permission on the test directory itself. 
Classic sudo passes the relative path through to execve() the same way, so
the two agree.  However, sudo-rs (the default sudo implementation since
Ubuntu 25.10) canonicalizes the command to an absolute path before
executing it, which requires search permission on every ancestor
directory.  When the kernel tree lives under a private home directory
(mode 0750, the Ubuntu default for new users since 21.04), the guard
passes but the execution fails with "command not found", and the test is
reported as a false FAIL:

  # running sudo -u nobody ./on-fault-limit
  sudo: './on-fault-limit': command not found
  # [FAIL]

Wrap the command in "sh -c" so that sudo only resolves the shell binary,
and the relative path is resolved by nobody's shell from the inherited
working directory, matching what the guard checks.  This is the only "sudo
-u nobody" invocation in the script; uid, cwd, rlimits (including
RLIMIT_MEMLOCK, which this test exercises) and the exit status are
unchanged through sh.

Verified on Ubuntu 26.04 (sudo-rs 0.2.13): the test now runs and passes
instead of failing.  Verified on Ubuntu 24.04 (sudo 1.9.15p5): behavior is
unchanged.

Link: https://lore.kernel.org/20260713092700.464376-1-injaeryou@gmail.com
Fixes: 5d2146a335 ("selftests/mm: skip mlock tests if nobody user can't read it")
Signed-off-by: Injae Ryou <injaeryou@gmail.com>
Cc: Brendan Jackman <jackmanb@google.com>
Cc: Brendan Jackman <brendan.jackman@linux.dev>
Cc: David Hildenbrand <david@kernel.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-08-06 18:56:56 -07:00
Yijia Wang
51f4bd13c3 selftests: mincore: count file-mmap readahead on both sides 
check_file_mmap() faults a page in the middle of a file mapping and
expects the mmap read-around path to make neighbouring pages resident. 
The test currently counts only pages after the faulted page.

That misses valid read-around on systems with large base page sizes.  On
arm64 with 64K pages and the default 128K readahead setting, the
read-around window is two pages wide and centred on the faulting page. 
Faulting page 32 makes pages 31 and 32 resident, so the forward-only scan
from page 33 reports ra_pages == 0 even though a neighbouring page was
brought in.

Keep the existing readahead assertion, but count resident neighbouring
pages on both sides of the faulted page.  This fixes the 64K-page false
failure without teaching the selftest to compute the expected readahead
window from sysfs or other implementation details.

Link: https://lore.kernel.org/20260713094319.771550-1-wangyijia.yeah@bytedance.com
Signed-off-by: Yijia Wang <wangyijia.yeah@bytedance.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-08-06 18:56:55 -07:00
Muchun Song
1edcd9d7e5 selftests/mm: remove obsolete hugetlb vmemmap test 
The hugetlb vmemmap selftest was added to check the old HVO layout where
tail vmemmap pages reused the head page.  That assumption no longer
matches the current HVO mapping layout.

HVO now keeps a private backing page for the head vmemmap page and remaps
redundant tail vmemmap pages to a shared read-only backing page.  The old
page flag check is therefore testing an obsolete implementation detail
rather than the current ABI or behavior.

Remove the stale test and its build and run entries.

[akpm@linux-foundation.org: don't clean old executables out of .gitignore]
  Link: https://lore.kernel.org/CAHk-=wiHK5_oBUdUiNAaevmN9f-ORe+QBqbRefAZaw-RbgEn3w@mail.gmail.com
Link: https://lore.kernel.org/20260710092427.3459121-1-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: Lorenzo Stoakes <ljs@kernel.org>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Reviewed-by: SJ Park <sj@kernel.org>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-08-04 19:19:05 -07:00
Lorenzo Stoakes
f1966d954b tools/testing/vma: output compared expression on ASSERT_[EQ, NE]() 
Update the macros to output the compared values at hex for easier debugging
when test asserts fail.

We have to be careful not to re-evaluate expressions as they may have
side-effects. So update the code to take local copies and use these for
both the test and the debug output.

Also remove unused IS_SET() macro.

Link: https://lore.kernel.org/20260710-b4-pre-scalable-cow-v2-33-2a5aa403d977@kernel.org
Signed-off-by: Lorenzo Stoakes <ljs@kernel.org>
Reviewed-by: Gregory Price <gourry@gourry.net>
Cc: Ackerley Tng <ackerleytng@google.com>
Cc: David Hildenbrand (Arm) <david@kernel.org>
Cc: Kai Huang <kai.huang@intel.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Pedro Falcato <pfalcato@suse.de>
Cc: SJ Park <sj@kernel.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Cc: Liam R. Howlett (Oracle) <liam@infradead.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-08-04 19:19:04 -07:00
Lorenzo Stoakes
fe95ccb1ba tools/testing/vma: default VMA, mm flag bits to 64-bit 
With all of the sanitisers turned on, setting the VMA and mm flag bits
depth to 128 by default results in overly long build times.

Reduce this to 64 - we can always manipulate these later for testing of
larger bitmaps as needed.

Link: https://lore.kernel.org/20260710-b4-pre-scalable-cow-v2-32-2a5aa403d977@kernel.org
Signed-off-by: Lorenzo Stoakes <ljs@kernel.org>
Reviewed-by: Gregory Price <gourry@gourry.net>
Cc: Ackerley Tng <ackerleytng@google.com>
Cc: David Hildenbrand (Arm) <david@kernel.org>
Cc: Kai Huang <kai.huang@intel.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Pedro Falcato <pfalcato@suse.de>
Cc: SJ Park <sj@kernel.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Cc: Liam R. Howlett (Oracle) <liam@infradead.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-08-04 19:19:04 -07:00
Lorenzo Stoakes
613562c29f mm/vma: introduce and use vma_set_pgoff() 
In order to lay the foundation for work that permits us to track the
virtual page offset of MAP_PRIVATE file-backed mappings, we abstract the
assignment of vma->vm_pgoff to vma_set_pgoff().

We additionally add a lock check here using the newly introduced
vma_assert_can_modify(). This asserts the VMA write lock if the VMA is
attached.

We also assert that, if this is an anonymous VMA and unfaulted, that its
(virtual) page offset is equal to the page offset of the VMA's address.

We must be careful about MAP_PRIVATE-/dev/zero which violates fundamental
assumptions about anonymous memory, so we check for !vma->vm_file after
using vma_is_anonymous() which these mappings satisfy.

Additionally, we only perform the assert if CONFIG_MMU is defined, as nommu
does not set vma->vm_pgoff = addr >> PAGE_SHIFT. This isn't really relevant
to rmap as it has no anon rmap (nor needs it), but we must avoid it
asserting falsely.

All of this logic is kept in assert_sane_pgoff() to keep things clear.

In order to maintain correctness given this assert, we also update
__install_special_mapping() to invoke vma_set_range() after it's set
vma->vm_ops (which determine whether the VMA is anonymous or not).

We do not use vma_set_pgoff() in vm_area_init_from(), as at the point of
forking, we don't necessarily have correct locking state.

Updating vma_set_range() covers most cases, but in addition to this we also
update insert_vm_struct(), compat_set_vma_from_desc() and nommu callers.

We also update vma_add_pgoff() and vma_sub_pgoff() to use vma_set_pgoff().

While we're here, we drop a BUG_ON() and update insert_vm_struct()'s
comment to reflect the fact anonymous mappings can be added here.

Finally, we update the CONFIG_MMU, CONFIG_PER_VMA_LOCK defines in the VMA
userland tests so IS_ENABLED() will work correctly with them.

No functional change intended.

Link: https://lore.kernel.org/20260710-b4-pre-scalable-cow-v2-29-2a5aa403d977@kernel.org
Signed-off-by: Lorenzo Stoakes <ljs@kernel.org>
Reviewed-by: Pedro Falcato <pfalcato@suse.de>
Reviewed-by: Gregory Price <gourry@gourry.net>
Reviewed-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Cc: Ackerley Tng <ackerleytng@google.com>
Cc: David Hildenbrand (Arm) <david@kernel.org>
Cc: Kai Huang <kai.huang@intel.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: SJ Park <sj@kernel.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Liam R. Howlett (Oracle) <liam@infradead.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-08-04 19:19:03 -07:00
Lorenzo Stoakes
6387563e6e mm/vma: update vma_shrink() to not pass start, pgoff parameters 
vma_shrink() is only used by relocate_vma_down() to shrink the tail of a
VMA. Therefore neither the start nor the pgoff parameters make any sense.

It seemed we were passing the pgoff parameter solely to satisfy
vma_set_range()'s requirement for pgoff being specified.

Since vma_set_range() is now isolated to vma.c, we can simply introduce
__vma_set_range() which sets only vma->vm_[start, end], and invoke this
instead, removing start and pgoff from vma_shrink() altogether.

No functional change intended.

Link: https://lore.kernel.org/20260710-b4-pre-scalable-cow-v2-26-2a5aa403d977@kernel.org
Signed-off-by: Lorenzo Stoakes <ljs@kernel.org>
Reviewed-by: Pedro Falcato <pfalcato@suse.de>
Reviewed-by: Gregory Price <gourry@gourry.net>
Reviewed-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Cc: Ackerley Tng <ackerleytng@google.com>
Cc: David Hildenbrand (Arm) <david@kernel.org>
Cc: Kai Huang <kai.huang@intel.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: SJ Park <sj@kernel.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Liam R. Howlett (Oracle) <liam@infradead.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-08-04 19:19:03 -07:00
Lorenzo Stoakes
775659f8fc mm/vma: make vma_set_range() static, drop insert_vm_struct() decl 
With __install_special_mapping() moved to vma.c, vma_set_range() can be
made into a static function there and is now completely isolated from the
rest of mm.

While we're here, we can also remove the insert_vm_struct() declaration
from mm.h - the function is implemented in vma.c and already declared in
vma.h, and has no users outside of mm.

Also update the VMA userland tests to reflect this change.

No functional change intended.

Link: https://lore.kernel.org/20260710-b4-pre-scalable-cow-v2-25-2a5aa403d977@kernel.org
Signed-off-by: Lorenzo Stoakes <ljs@kernel.org>
Reviewed-by: Pedro Falcato <pfalcato@suse.de>
Reviewed-by: Gregory Price <gourry@gourry.net>
Reviewed-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Cc: Ackerley Tng <ackerleytng@google.com>
Cc: David Hildenbrand (Arm) <david@kernel.org>
Cc: Kai Huang <kai.huang@intel.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: SJ Park <sj@kernel.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Liam R. Howlett (Oracle) <liam@infradead.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-08-04 19:19:02 -07:00
Lorenzo Stoakes
e65f4dfac1 mm/vma: introduce vma_assert_can_modify() 
vma_assert_write_locked() and vma_assert_attached() are useful for their
own purposes, however VMA code absolutely does allow the modification of
non-write locked VMAs if they are at that point detached (i.e. unreachable
from anywhere).

It's therefore useful to be able to assert that a VMA is either
detached (modification doesn't matter) or write locked (you're explicitly
locked for modification).

Therefore introduce vma_assert_can_modify() for this purpose.

While we're here, make vma_is_attached() available generally - if
!CONFIG_PER_VMA_LOCK, then there's no sense in which a VMA is
detached (vma_mark_detached() is a noop), so have this default to true in
this case.

Also update VMA userland tests to reflect this change, correcting the
previously open-coded vma_assert_[attached,detached]() there.

Link: https://lore.kernel.org/20260710-b4-pre-scalable-cow-v2-22-2a5aa403d977@kernel.org
Signed-off-by: Lorenzo Stoakes <ljs@kernel.org>
Reviewed-by: Gregory Price <gourry@gourry.net>
Reviewed-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Cc: Ackerley Tng <ackerleytng@google.com>
Cc: David Hildenbrand (Arm) <david@kernel.org>
Cc: Kai Huang <kai.huang@intel.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Pedro Falcato <pfalcato@suse.de>
Cc: SJ Park <sj@kernel.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Liam R. Howlett (Oracle) <liam@infradead.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-08-04 19:19:01 -07:00
Lorenzo Stoakes
ff8fbc9e08 mm/vma: remove duplicative vma_pgoff_offset() helper 
This is doing what linear_page_index() does, so eliminate it and replace it
with linear_page_index().

Update the VMA userland tests to reflect this change.

No functional change intended.

Link: https://lore.kernel.org/20260710-b4-pre-scalable-cow-v2-20-2a5aa403d977@kernel.org
Signed-off-by: Lorenzo Stoakes <ljs@kernel.org>
Reviewed-by: Pedro Falcato <pfalcato@suse.de>
Reviewed-by: Gregory Price <gourry@gourry.net>
Reviewed-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Cc: Ackerley Tng <ackerleytng@google.com>
Cc: David Hildenbrand (Arm) <david@kernel.org>
Cc: Kai Huang <kai.huang@intel.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: SJ Park <sj@kernel.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Liam R. Howlett (Oracle) <liam@infradead.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-08-04 19:19:01 -07:00
Lorenzo Stoakes
b1e71c05fa mm/rmap: rename anon_vma_interval_tree_*() to anon_rmap_tree_*() 
To be consistent with the newly renamed mapping_rmap_tree_*(), rename the
anon_vma_interval_tree_*() helpers to anon_rmap_tree_*().

No functional change intended.

Link: https://lore.kernel.org/20260710-b4-pre-scalable-cow-v2-11-2a5aa403d977@kernel.org
Signed-off-by: Lorenzo Stoakes <ljs@kernel.org>
Reviewed-by: Gregory Price <gourry@gourry.net>
Reviewed-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Cc: Ackerley Tng <ackerleytng@google.com>
Cc: David Hildenbrand (Arm) <david@kernel.org>
Cc: Kai Huang <kai.huang@intel.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Pedro Falcato <pfalcato@suse.de>
Cc: SJ Park <sj@kernel.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Liam R. Howlett (Oracle) <liam@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-08-04 19:18:58 -07:00
Lorenzo Stoakes
68364437ec mm/rmap: parameterise anon_vma_interval_tree_*() by anon_vma 
Similar to what we did with mapping_rmap_tree*(), let's declare
anon_vma_interval_tree*() in terms of anon_vma rather than rb_root_cached.

In each case the rb tree referenced is &anon_vma->rb_root, so just pass
anon_vma and the functions can figure this out themselves.

Also update the VMA userland tests to reflect the change.

No functional change intended.

Link: https://lore.kernel.org/20260710-b4-pre-scalable-cow-v2-9-2a5aa403d977@kernel.org
Signed-off-by: Lorenzo Stoakes <ljs@kernel.org>
Reviewed-by: Pedro Falcato <pfalcato@suse.de>
Reviewed-by: Gregory Price <gourry@gourry.net>
Reviewed-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Cc: Ackerley Tng <ackerleytng@google.com>
Cc: David Hildenbrand (Arm) <david@kernel.org>
Cc: Kai Huang <kai.huang@intel.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: SJ Park <sj@kernel.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Liam R. Howlett (Oracle) <liam@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-08-04 19:18:58 -07:00
Lorenzo Stoakes
4b7a90a48b mm/rmap: rename vma_interval_tree_*() to mapping_rmap_tree_*() 
The family of vma_interval_tree_() functions manipulate the
address_space (which, of course, is generally referred to as 'mapping')
reverse mapping, but are named the 'VMA' interval tree.

VMAs may be mapped by an anon_vma, an address_space, or both. Therefore
calling the mapping interval tree a 'VMA' interval tree is rather
confusing.

This is also inconsistent with the anon_vma_interval_tree_*() functions
which explicitly reference the rmap object to which they pertain.

Rename the vma_interval_tree_*() functions to mapping_rmap_tree_*() to
correct this.

We will rename the anon rmap functions similarly in a subsequent patch.

No functional change intended.

Link: https://lore.kernel.org/20260710-b4-pre-scalable-cow-v2-8-2a5aa403d977@kernel.org
Signed-off-by: Lorenzo Stoakes <ljs@kernel.org>
Reviewed-by: Gregory Price <gourry@gourry.net>
Reviewed-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Cc: Ackerley Tng <ackerleytng@google.com>
Cc: David Hildenbrand (Arm) <david@kernel.org>
Cc: Kai Huang <kai.huang@intel.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Pedro Falcato <pfalcato@suse.de>
Cc: SJ Park <sj@kernel.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Liam R. Howlett (Oracle) <liam@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-08-04 19:18:58 -07:00
Lorenzo Stoakes
7a67b96af0 mm/rmap: parameterise vma_interval_tree_*() by address_space 
The file-backed mapping interval tree functions vma_interval_tree_*()
accept a raw rb_root_cached pointer to determine the tree in which they are
operating.

However, in each case, this is always associated with an address_space data
type.

So simply pass a pointer to that instead to simplify the code, and more
clearly differentiate between these operations and those concerning
anonymous mappings.

While we're here, make the generated interval tree functions static as they
do not need to be used externally (any previously existing external users
have now been removed).

We also rename VMA parameters from 'node' to 'vma' as calling this a node
is simply confusing, update the input index types to pgoff_t since they
reference page offsets and rename the parameters to pgoff_start and
pgoff_last.

No functional change intended.

Link: https://lore.kernel.org/20260710-b4-pre-scalable-cow-v2-6-2a5aa403d977@kernel.org
Signed-off-by: Lorenzo Stoakes <ljs@kernel.org>
Reviewed-by: Pedro Falcato <pfalcato@suse.de>
Reviewed-by: Gregory Price <gourry@gourry.net>
Reviewed-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Cc: Ackerley Tng <ackerleytng@google.com>
Cc: David Hildenbrand (Arm) <david@kernel.org>
Cc: Kai Huang <kai.huang@intel.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: SJ Park <sj@kernel.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Liam R. Howlett (Oracle) <liam@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-08-04 19:18:57 -07:00
Lorenzo Stoakes
1219731c49 mm: introduce and use vma_end_pgoff() 
We already have vma_last_pgoff() which retrieves the last page offset
within a VMA.

However, code often wishes to span a page offset range, which requires the
exclusive end of this range.

So provide this in vma_end_pgoff() and update vma_last_pgoff() to use this
function.

Also update the VMA userland tests to reflect the change.

No functional change intended.

Link: https://lore.kernel.org/20260710-b4-pre-scalable-cow-v2-4-2a5aa403d977@kernel.org
Signed-off-by: Lorenzo Stoakes <ljs@kernel.org>
Reviewed-by: Gregory Price <gourry@gourry.net>
Reviewed-by: Pedro Falcato <pfalcato@suse.de>
Reviewed-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Cc: Ackerley Tng <ackerleytng@google.com>
Cc: David Hildenbrand (Arm) <david@kernel.org>
Cc: Kai Huang <kai.huang@intel.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: SJ Park <sj@kernel.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Liam R. Howlett (Oracle) <liam@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-08-04 19:18:56 -07:00
Lorenzo Stoakes
3542bc07f4 tools/testing/vma: use vma_start_pgoff() in merge tests 
Now we have the vma_start_pgoff() helper, update the merge tests to make
use of it for consistency.

No functional change intended.

Link: https://lore.kernel.org/20260710-b4-pre-scalable-cow-v2-3-2a5aa403d977@kernel.org
Signed-off-by: Lorenzo Stoakes <ljs@kernel.org>
Reviewed-by: Pedro Falcato <pfalcato@suse.de>
Reviewed-by: Gregory Price <gourry@gourry.net>
Reviewed-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Reviewed-by: Liam R. Howlett (Oracle) <liam@infradead.org>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Cc: Ackerley Tng <ackerleytng@google.com>
Cc: David Hildenbrand (Arm) <david@kernel.org>
Cc: Kai Huang <kai.huang@intel.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: SJ Park <sj@kernel.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-08-04 19:18:56 -07:00
Lorenzo Stoakes
995f0eed5e mm: move vma_start_pgoff() into mm.h and clean up 
Patch series "mm: make VMA page offset handling more consistent", v2.

This series performs a series of cleanups and improvements around how the
vma->vm_pgoff field is used.

Folios belonging to file-backed mappings are simply indexed by the page
offset within the file they map (excepting pfnmap and driver mappings
which sometimes do things different).

However, anonymous folios belonging to pure anonymous mappings are indexed
by their "virtual" page offset, which is equal to addr >> PAGE_SHIFT at
the time at which the VMA was first faulted in.

The page offset of a VMA is stored in vma->vm_pgoff and indicates the page
offset of the start of the VMA range, whether it be file-backed or
anonymous.

The work here both cleans up how we reference this field, as well as
laying the foundations for a future series which addresses the
inconsistency of CoW'd folios in MAP_PRIVATE-file backed mappings, which
are indexed as if they were file-backed but behave as if they were
anonymous.

This future series will make it such that all anonymous folios are indexed
by virtual page offset whether belonging to VMAs who satisfy
vma_is_anonymous() or MAP_PRIVATE-mapped file-backed mappings.

This series:

* Exposes vma_start_pgoff() and updates the kernel to use it consistently.
* Adds and uses the useful vma_end_pgoff() helper.
* Parameterises the file-backed mapping helpers vma_interval_tree_*()
  by address_space rather than rb_root_cached.
* Renames: the misleadingly-named vma_interval_tree_*() helpers to
  mapping_rmap_tree_*() to be consistent with the renamed
  anon_rmap_tree_*().
* Parameterises anon_rmap_tree_*() by anon_vma.
* Moves mm/interval_tree.c to the rmap section.
* Adds vmg_*() helpers for page offset.
* Clarifies the confusing vmg_adjust_set_range() function.
* Introduces linear_page_delta() to provide relative pgoff within a VMA.
* Replaces open-coded versions of linear_page_delta() and
  linear_page_index() with invocations of these functions.
* Introduces and uses vma_assert_can_modify() to account for whether a VMA
  can be modified (detached or write locked).
* Adds and uses vma_[add,sub]_pgoff() to adjust VMA page offset.
* Moves __install_special_mapping() to vma.c.
* Makes vma_set_range() static and internal to vma.c.
* Introduces and makes use of vma_set_pgoff().
* Fixes incorrect vma.h header inclusion.
* Defaults VMA userland tests to 64-bit vma flags size.
* Updates VMA userland tests to give better output on failure.
* Various smaller cleanups.
* Updated the vma_set_pgoff() assert to account for MAP_PRIVATE /dev/zero
  correctly.


This patch (of 33):

vma_last_pgoff() already lives there, so it's a bit odd to keep
vma_start_pgoff() in mm/interval_tree.c. Move them together.

These each return unsigned long, which pgoff_t is typedef'd to. Make this
consistent and have these functions return pgoff_t instead.

Additionally, express vma_last_pgoff() in terms of vma_start_pgoff(), since
we wrap the vma->vm_pgoff access, we may as well use it here.

Also while we're here, const-ify the VMA and cleanup a bit.

Also update the VMA userland tests to reflect the change.

No functional change intended.

Link: https://lore.kernel.org/20260710-b4-pre-scalable-cow-v2-0-2a5aa403d977@kernel.org
Link: https://lore.kernel.org/20260710-b4-pre-scalable-cow-v2-1-2a5aa403d977@kernel.org
Signed-off-by: Lorenzo Stoakes <ljs@kernel.org>
Reviewed-by: Gregory Price <gourry@gourry.net>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Reviewed-by: Pedro Falcato <pfalcato@suse.de>
Reviewed-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Reviewed-by: Liam R. Howlett (Oracle) <liam@infradead.org>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Cc: Ackerley Tng <ackerleytng@google.com>
Cc: Kai Huang <kai.huang@intel.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: SJ Park <sj@kernel.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-08-04 19:18:56 -07:00
Stanislav Kinsburskii
9365813cad selftests/mm: add HMM test for mmap lock-dropping faults 
Add test_hmm coverage for the HMM lock-dropping fault path.  The test
module gets a new HMM_DMIRROR_READ_UNLOCKED ioctl that calls
hmm_range_fault_unlocked_timeout() with a timeout of 0, exercising the
unbounded retry mode while allowing the mmap lock to be dropped during
fault handling.

Add a userfaultfd_read selftest that registers an anonymous mapping with
UFFDIO_REGISTER_MODE_MISSING, services the faults from a handler thread
with UFFDIO_COPY, and verifies that HMM can read back the data supplied by
the handler.  This exercises the path where handle_mm_fault() drops
mmap_lock and hmm_range_fault_unlocked_timeout() restarts the walk
internally.

Assisted-by: GitHub-Copilot:claude-opus-4.6
Link: https://lore.kernel.org/20260723-hmm-v10-v11-3-c55b003a4b61@gmail.com
Signed-off-by: Stanislav Kinsburskii <skinsburskii@gmail.com>
Cc: Danilo Krummrich <dakr@kernel.org>
Cc: Dave Airlie <airlied@gmail.com>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dexuan Cui <decui@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: K. Y. Srinivasan <kys@microsoft.com>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lizhi Hou <lizhi.hou@amd.com>
Cc: Long Li <longli@microsoft.com>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Lyude <lyude@redhat.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Oded Gabbay <ogabbay@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Thomas Zimemrmann <tzimmermann@suse.de>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Wei Liu <wei.liu@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-08-04 19:18:54 -07:00
Sayali Patil
4e1fbffb33 selftests/mm: fix ternary operator precedence in ksm_tests 
The KSM selftest uses conditional expressions to skip accesses to
merge_across_nodes on systems without NUMA support.  However, the ternary
operator is combined with logical OR without parentheses:

a || numa_available() ? 0 : b || c

Due to operator precedence rules, this is parsed as:

(a || numa_available()) ? 0 : (b || c)

instead of the intended:

a || (numa_available() ? 0 : b) || c

Add parentheses around the conditional expressions to ensure the
correct evaluation order.

Link: https://lore.kernel.org/ce859430287ed2642848c933a90eb9a69da361f0.1783446924.git.sayalip@linux.ibm.com
Fixes: 9aa1af954d ("selftests: vm: check numa_available() before operating "merge_across_nodes" in ksm_tests")
Signed-off-by: Sayali Patil <sayalip@linux.ibm.com>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Liam Howlett <liam@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-08-04 19:18:48 -07:00
Sayali Patil
15828a150c selftests/mm: fix ksm NUMA merge test for systems with memoryless NUMA nodes 
The KSM NUMA merge test allocates identical pages on different NUMA nodes
and verifies KSM behavior with merge_across_nodes enabled and disabled.

On systems with memoryless NUMA nodes, for example:
 #numactl  -H
      available: 2 nodes (0,4)
      .....
      node 0 cpus: 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
      node 0 size: 14825 MB
      node 0 free: 1382 MB
      node 4 cpus:
      node 4 size: 0 MB
      node 4 free: 0 MB

the test may attempt to allocate memory on a node without memory, causing
numa_alloc_onnode() to fail and resulting in a spurious test failure.

The test currently checks numa_num_configured_nodes() to determine whether
sufficient NUMA nodes are available.  However, configured nodes do not
necessarily have memory.

Reuse the existing get_first_mem_node() and get_next_mem_node() helpers to
locate NUMA nodes that actually contain memory, and skip the test when
fewer than two such nodes are available.

Before patch:
       ---------------------------
	running ./ksm_tests -N -m 1
       ---------------------------
        mbind: Invalid argument
        ok 1 KSM NUMA merging
	Totals: pass:1 fail:0 xfail:0 xpass:0 skip:0 error:0
        [PASS]
       ok 1 ksm_tests -N -m 1
       ---------------------------
        running ./ksm_tests -N -m 0
       ---------------------------
        mbind: Invalid argument
        not ok 1 KSM NUMA merging
	Totals: pass:0 fail:1 xfail:0 xpass:0 skip:0 error:0
        [FAIL]
       not ok 2 ksm_tests -N -m 0 # exit=1

After patch:
       ---------------------------
        running ./ksm_tests -N -m 1
       ---------------------------
        At least 2 NUMA nodes with memory must be available
	ok 1
	SKIP KSM NUMA merging
	Totals: pass:0 fail:0 xfail:0 xpass:0 skip:1 error:0
        [PASS]
        ok 1 ksm_tests -N -m 1
       ---------------------------
        running ./ksm_tests -N -m 0
       ---------------------------
        At least 2 NUMA nodes with memory must be available
	ok 1
	SKIP KSM NUMA merging
	Totals: pass:0 fail:0 xfail:0 xpass:0 skip:1 error:0
        [PASS]
        ok 2 ksm_tests -N -m 0

Link: https://lore.kernel.org/78a3b0e3fb94004c0710872c5bab6f7381b7d63c.1783446924.git.sayalip@linux.ibm.com
Fixes: e3820ab252 ("selftest/vm: fix ksm selftest to run with different NUMA topologies")
Co-developed-by: David Hildenbrand (Arm) <david@kernel.org>
Signed-off-by: David Hildenbrand (Arm) <david@kernel.org>
Signed-off-by: Sayali Patil <sayalip@linux.ibm.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Liam Howlett <liam@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-08-04 19:18:47 -07:00
Sayali Patil
5c4c48ff5a selftests/mm: handle EINVAL when configuring gigantic hugepages 
Patch series "selftests/mm: avoid false failures in hugetlb and KSM
tests", v3.

This series fixes issues in the hugetlb and KSM MM selftest categories
that can report failures when the prerequisites for the tests are not
satisfied.

Patch 1 updates the hugetlb selftest helpers to handle -EINVAL when
attempting to configure gigantic HugeTLB pages via nr_hugepages.  PowerPC
hash MMU pSeries systems expose gigantic hugepage sizes but do not allow
runtime allocation of such pages, causing the sysfs write to fail.  Handle
this case gracefully and continue running the test instead of aborting.

Patch 2 fixes the KSM NUMA merge test on systems with memoryless NUMA
nodes.  The test currently relies on the number of configured NUMA nodes
and may attempt allocations on nodes that have no memory, resulting in
spurious failures.  Use the existing helpers to identify NUMA nodes that
contain memory and skip the test when fewer than two such nodes are
available.

Patch 3 fixes a pre-existing operator precedence issue in ksm_tests, where
a ternary expression combined with logical OR operators could be evaluated
differently than intended.  Added parentheses to ensure the correct
evaluation order.

These changes improve handling of unsupported test configurations and
unmet test prerequisites, avoiding spurious failures.


This patch (of 3):

Some MM selftests attempt to configure the amount of HugeTLB pages of
different sizes by writing to nr_hugepages.

PowerPC hash MMU pSeries systems advertise gigantic hugepage sizes but do
not support runtime allocation of such pages, writes to the corresponding
nr_hugepages file fail with -EINVAL.  This causes the test to bail out
even though the failure is due to a platform limitation rather than the
functionality being tested.

Ignore -EINVAL when configuring nr_hugepages so that tests continue to run
on systems where gigantic hugepage allocation is unsupported.

Before patch:
   -------------------------
   running ./hugetlb-madvise
   -------------------------
   TAP version 13
   1..1
     [INFO] detected hugetlb page size: 16777216 KiB
     [INFO] detected hugetlb page size: 16384 KiB
    ok 1 MADV_DONTNEED and MADV_REMOVE on hugetlb
    Totals: pass:1 fail:0 xfail:0 xpass:0 skip:0 error:0
    Bail out! /sys/kernel/mm/hugepages/hugepages-16777216kB/nr_hugepages
    write(0) failed: Invalid argument
    Totals: pass:0 fail:0 xfail:0 xpass:0 skip:0 error:0
    [FAIL]

After patch:
   -------------------------
   running ./hugetlb-madvise
   -------------------------
   TAP version 13
   1..1
    [INFO] detected hugetlb page size: 16777216 KiB
    [INFO] detected hugetlb page size: 16384 KiB
   ok 1 MADV_DONTNEED and MADV_REMOVE on hugetlb
   Totals: pass:1 fail:0 xfail:0 xpass:0 skip:0 error:0
   [PASS]

Link: https://lore.kernel.org/cover.1783446924.git.sayalip@linux.ibm.com
Link: https://lore.kernel.org/2e3b585cbb30b2fc495dcd49d75de6f6da61861c.1783446924.git.sayalip@linux.ibm.com
Fixes: 27477b28b7 ("selftests/mm: hugepage_settings: add APIs to get and set nr_hugepages")
Co-developed-by: David Hildenbrand (Arm) <david@kernel.org>
Signed-off-by: David Hildenbrand (Arm) <david@kernel.org>
Signed-off-by: Sayali Patil <sayalip@linux.ibm.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Liam Howlett <liam@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-08-04 19:18:47 -07:00
Hongfu Li
f421d67d2c selftests/mm: fix memleak in migration benchmark 
Several early return paths in run_migration_benchmark() skip
hmm_buffer_free(), leaking the buffer.  Replace with a single cleanup
label.

Link: https://lore.kernel.org/20260709081843.1451202-1-lihongfu@kylinos.cn
Fixes: 271a7b2e3c ("selftests/mm/hmm-tests: new throughput tests including THP")
Signed-off-by: Hongfu Li <lihongfu@kylinos.cn>
Reviewed-by: David Hildenbrand (Arm) <david@kernel.org>
Reviewed-by: SJ Park <sj@kernel.org>
Acked-by: Balbir Singh <balbirs@nvidia.com>
Reviewed-by: Lorenzo Stoakes <ljs@kernel.org>
Reviewed-by: Balbir Singh <balbirs@nvidia.com>
Reviewed-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>
Cc: Hongfu Li <lihongfu@kylinos.cn>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-08-04 19:18:47 -07:00
Mike Rapoport (Microsoft)
55ed40abb2 mm: split out mm_init and memblock declarations from internal.h 
Patch series "mm: split a couple of headers from internal.h", v2.

mm/internal.h becomes more and more bloated.

Split declarations related to mm_init, memblock, vmalloc and sparse into
new headers.


This patch (of 3):

mm/internal.h becomes more and more bloated.

Move declarations for related to mm/mm_init.c and mm/memblock.c to a new
mm/mm_init.h header.

No functional changes.

[rppt@kernel.org: split stubfs from internal.h to mm_init.h]
  Link: https://lore.kernel.org/alJd1BLypyK9Mpaw@kernel.org
Link: https://lore.kernel.org/20260709-internal-h-v2-0-695631425968@kernel.org
Link: https://lore.kernel.org/20260709-internal-h-v2-1-695631425968@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Acked-by: Muchun Song <muchun.song@linux.dev>
Acked-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Acked-by: Lorenzo Stoakes <ljs@kernel.org>
Acked-by: Pratyush Yadav <pratyush@kernel.org>
Acked-by: SJ Park <sj@kernel.org>
Cc: Alexander Graf <graf@amazon.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Brendan Jackman <jackmanb@google.com>
Cc: Brendan Jackman <brendan.jackman@linux.dev>
Cc: Dennis Zhou <dennis@kernel.org>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Marco Elver <elver@google.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: "Uladzislau Rezki (Sony)" <urezki@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-08-04 19:18:45 -07:00
xu xin
1695841621 ksm: add mremap selftests for ksm_rmap_walk 
The existing tools/testing/selftests/mm/rmap.c has already one testcase
for ksm_rmap_walk in TEST_F(migrate, ksm), which takes use of migration of
page from one NUMA node to another NUMA node.  However, it just lacks the
scenario of mremapped VMAs.

We add the calling of mremap() and then trigger KSM to merge pages before
migrating, which is specifically to test an optimization which is
introduced by this patch ("ksm: Optimize rmap_walk_ksm by passing a
suitable address pgoff").

This test can reproduce the issue that Hugh points out at
https://lore.kernel.org/all/02e1b8df-d568-8cbb-b8f6-46d5476d9d75@google.com/

Link: https://lore.kernel.org/20260703162637070FU4ekl58Hw_Z7OSuJryZB@zte.com.cn
Signed-off-by: xu xin <xu.xin16@zte.com.cn>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Cc: Chengming Zhou <chengming.zhou@linux.dev>
Cc: Hugh Dickins <hughd@google.com>
Cc: "Liam R. Howlett" <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Wang Yaxin <wang.yaxin@zte.com.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-08-04 19:18:45 -07:00
Kiryl Shutsemau (Meta)
3628215f7f selftests/mm: add userfaultfd RWP tests 
Coverage for UFFDIO_REGISTER_MODE_RWP and UFFDIO_RWPROTECT:

  rwp-async          async mode — touch pages, verify permissions are
                     auto-restored without a message
  rwp-sync           sync mode — access blocks, handler resolves via
                     UFFDIO_RWPROTECT
  rwp-pagemap        PAGEMAP_SCAN reports still-cold pages via
                     inverted PAGE_IS_ACCESSED
  rwp-mprotect       RWP survives mprotect(PROT_NONE) ->
                     mprotect(PROT_READ|PROT_WRITE) round-trip
  rwp-gup            GUP walks through a protnone RWP PTE (pipe
                     write/read drives the GUP path)
  rwp-async-toggle   UFFDIO_SET_MODE flips between sync and async
                     without re-registering
  rwp-close          closing the uffd restores page permissions
  rwp-fork           RWP survives fork() with EVENT_FORK; child's
                     PTEs keep the uffd bit
  rwp-fork-pin       RWP survives fork() on an RO-longterm-pinned
                     anon page (forces copy_present_page()); child
                     read auto-resolves and clears the bit, proving
                     PAGE_NONE was in place
  rwp-wp-exclusive   register with MODE_WP|MODE_RWP returns -EINVAL

All tests run against anon, shmem, shmem-private, hugetlb, and
hugetlb-private memory, except rwp-fork-pin which is anon-only —
copy_present_page() is the private-anon pinned-exclusive fork path.

Snapshot the RWP additions into tools/include/uapi/linux/userfaultfd.h so
the selftest builds without requiring "make headers" first, matching the
mechanism established by commit 580ea358af ("selftests/mm: fix
additional build errors for selftests").

Link: https://lore.kernel.org/ak-Z9KO2mP9HMOPW@thinkstation
Signed-off-by: Kiryl Shutsemau <kas@kernel.org>
Assisted-by: Claude:claude-opus-4-6
Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: David Hildenbrand <david@kernel.org>
Cc: James Houghton <jthoughton@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Liam Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-08-04 19:18:39 -07:00
wang wei
d25711a9f3 selftests/damon: check correct path in ensure_file() not_exist case 
In the ensure_file() function, the "not_exist" code path checks whether
$dir exists as a regular file.  However, the intent is to verify that the
target file ($file) does not exist, not the $dir.  Testing $dir makes the
existence check effectively useless -- it tests the wrong path and thus
never catches the case where the file is unexpectedly present.

Replace $dir with $file so the not_exist verification targets the correct
path.

Link: https://lore.kernel.org/20260706134305.5224-1-a929244872@163.com
Signed-off-by: wang wei <a929244872@163.com>
Reviewed-by: SJ Park <sj@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-08-04 19:18:29 -07:00
Andrew Morton
330f108fd3 Merge branch 'mm-hotfixes-stable' into mm-stable in order to pick up 
vmscan.c changes which are required by "memcg: bail out proactive reclaim
when memcg is dying".
 2026-08-04 19:15:12 -07:00
SJ Park
51bd0de225 selftests/damon/drgn_dump_damon_status: do not dump nr_accesses_bp 
drgn_dump_damon_status is dumping nr_accesses_bp field for future use
case.  nr_accesses_bp is not being used for a real purpose, though.  Hence
there will be no future test for it.  Do not dump it.

Link: https://lore.kernel.org/20260630040812.149729-13-sj@kernel.org
Signed-off-by: SJ Park <sj@kernel.org>
Cc: Brendan Higgins <brendan.higgins@linux.dev>
Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2026-07-30 19:40:35 -07:00