Commit Graph

1398012 Commits

Author SHA1 Message Date
Lu Baolu
72f98ef9a4 iommu: disable SVA when CONFIG_X86 is set
Patch series "Fix stale IOTLB entries for kernel address space", v7.

This proposes a fix for a security vulnerability related to IOMMU Shared
Virtual Addressing (SVA).  In an SVA context, an IOMMU can cache kernel
page table entries.  When a kernel page table page is freed and
reallocated for another purpose, the IOMMU might still hold stale,
incorrect entries.  This can be exploited to cause a use-after-free or
write-after-free condition, potentially leading to privilege escalation or
data corruption.

This solution introduces a deferred freeing mechanism for kernel page
table pages, which provides a safe window to notify the IOMMU to
invalidate its caches before the page is reused.


This patch (of 8):

In the IOMMU Shared Virtual Addressing (SVA) context, the IOMMU hardware
shares and walks the CPU's page tables.  The x86 architecture maps the
kernel's virtual address space into the upper portion of every process's
page table.  Consequently, in an SVA context, the IOMMU hardware can walk
and cache kernel page table entries.

The Linux kernel currently lacks a notification mechanism for kernel page
table changes, specifically when page table pages are freed and reused. 
The IOMMU driver is only notified of changes to user virtual address
mappings.  This can cause the IOMMU's internal caches to retain stale
entries for kernel VA.

Use-After-Free (UAF) and Write-After-Free (WAF) conditions arise when
kernel page table pages are freed and later reallocated.  The IOMMU could
misinterpret the new data as valid page table entries.  The IOMMU might
then walk into attacker-controlled memory, leading to arbitrary physical
memory DMA access or privilege escalation.  This is also a
Write-After-Free issue, as the IOMMU will potentially continue to write
Accessed and Dirty bits to the freed memory while attempting to walk the
stale page tables.

Currently, SVA contexts are unprivileged and cannot access kernel
mappings.  However, the IOMMU will still walk kernel-only page tables all
the way down to the leaf entries, where it realizes the mapping is for the
kernel and errors out.  This means the IOMMU still caches these
intermediate page table entries, making the described vulnerability a real
concern.

Disable SVA on x86 architecture until the IOMMU can receive notification
to flush the paging cache before freeing the CPU kernel page table pages.

Link: https://lkml.kernel.org/r/20251022082635.2462433-1-baolu.lu@linux.intel.com
Link: https://lkml.kernel.org/r/20251022082635.2462433-2-baolu.lu@linux.intel.com
Fixes: 26b25a2b98 ("iommu: Bind process address spaces to devices")
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Suggested-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Betkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jann Horn <jannh@google.com>
Cc: Jean-Philippe Brucker <jean-philippe@linaro.org>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Kevin Tian <kevin.tian@intel.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Robin Murohy <robin.murphy@arm.com>
Cc: Thomas Gleinxer <tglx@linutronix.de>
Cc: "Uladzislau Rezki (Sony)" <urezki@gmail.com>
Cc: Vasant Hegde <vasant.hegde@amd.com>
Cc: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Cc: Yi Lai <yi1.lai@intel.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-16 17:28:16 -08:00
Shakeel Butt
5ff592bec7 memcg: manually uninline __memcg_memory_event
__memcg_memory_event() has been unnecessarily marked inline even when it
is not really performance critical.  It is usually called to track extreme
conditions.  Over the time, it has evolved to include more functionality
and inlining it is causing more harm.

Before the patch:
$ size mm/memcontrol.o net/ipv4/tcp_input.o net/ipv4/tcp_output.o
   text    data     bss     dec     hex filename
  35645   10574    4192   50411    c4eb mm/memcontrol.o
  54738    1658       0   56396    dc4c net/ipv4/tcp_input.o
  34644    1065       0   35709    8b7d net/ipv4/tcp_output.o

After the patch:
$ size mm/memcontrol.o net/ipv4/tcp_input.o net/ipv4/tcp_output.o
   text    data     bss     dec     hex filename
  35137   10446    4192   49775    c26f mm/memcontrol.o
  54322    1562       0   55884    da4c net/ipv4/tcp_input.o
  34492    1017       0   35509    8ab5 net/ipv4/tcp_output.o

[akpm@linux-foundation.org: use EXPORT_SYMBOL_GPL for __memcg_memory_event, per Michal and Christoph]
Link: https://lkml.kernel.org/r/20251021234425.1885471-1-shakeel.butt@linux.dev
Signed-off-by: Shakeel Butt <shakeel.butt@linux.dev>
Acked-by: SeongJae Park <sj@kernel.org>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-16 17:28:16 -08:00
Vishal Moola (Oracle)
a061578043 mm/vmalloc: request large order pages from buddy allocator
Sometimes, vm_area_alloc_pages() will want many pages from the buddy
allocator.  Rather than making requests to the buddy allocator for at most
100 pages at a time, we can eagerly request large order pages a smaller
number of times.

We still split the large order pages down to order-0 as the rest of the
vmalloc code (and some callers) depend on it.  We still defer to the bulk
allocator and fallback path in case of order-0 pages or failure.

Running 1000 iterations of allocations on a small 4GB system finds:

1000 2mb allocations:
	[Baseline]			[This patch]
	real    46.310s			real    0m34.582
	user    0.001s			user    0.006s
	sys     46.058s			sys     0m34.365s

10000 200kb allocations:
	[Baseline]			[This patch]
	real    56.104s			real    0m43.696
	user    0.001s			user    0.003s
	sys     55.375s			sys     0m42.995s

Link: https://lkml.kernel.org/r/20251021194455.33351-2-vishal.moola@gmail.com
Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Reviewed-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-16 17:28:15 -08:00
Jing Su
645a3c4243 mm/vmstat: fix indentation in fold_diff function
Adjust misaligned braces in fold_diff() to improve code readability and
maintain consistent coding style.

[akpm@linux-foundation.org: add braces, per Vlastimil & Liam]
Link: https://lkml.kernel.org/r/aPc4I/8zXCGyiapN@pilot-ThinkCentre-M930t-N000
Signed-off-by: Jing Su <jingsusu@didiglobal.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reviewed-by: Donet Tom <donettom@linux.ibm.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Dev Jain <dev.jain@arm.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-16 17:28:15 -08:00
William Kucharski
fe62415c9b mm: remove reference to destructor in comment in calculate_sizes()
The commit that removed support for destructors from kmem_cache_alloc()
never removed the comment regarding destructors in the explanation of the
possible relocation of the free pointer in calculate_sizes().

Link: https://lkml.kernel.org/r/20251021110004.2209008-1-william.kucharski@oracle.com
Fixes: 20c2df83d2 ("mm: Remove slab destructors from kmem_cache_create().")
Signed-off-by: William Kucharski <william.kucharski@oracle.com>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Reviewed-by: Christoph Lameter (Ampere) <cl@gentwo.org>
Acked-by: SeongJae Park <sj@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Harry Yoo <harry.yoo@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-16 17:28:15 -08:00
Leon Hwang
2da6fe91c2 mm/khugepaged: factor out common logic in [scan,alloc]_sleep_millisecs_store()
Both scan_sleep_millisecs_store() and alloc_sleep_millisecs_store()
perform the same operations: parse the input value, update their
respective sleep interval, reset khugepaged_sleep_expire, and wake up the
khugepaged thread.

Factor out this duplicated logic into a helper function
__sleep_millisecs_store(), and simplify both store functions.

No functional change intended.

Link: https://lkml.kernel.org/r/20251021134431.26488-1-leon.hwang@linux.dev
Signed-off-by: Leon Hwang <leon.hwang@linux.dev>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Lance Yang <lance.yang@linux.dev>
Acked-by: David Hildenbrand <david@redhat.com>
Acked-by: Nico Pache <npache@redhat.com>
Reviewed-by: Dev Jain <dev.jain@arm.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-16 17:28:15 -08:00
Swaraj Gaikwad
fae4e86024 mm/damon/sysfs: remove misleading todo comment in nid_show()
The TODO comment in nid_show() suggested returning an error if the goal
was not using nid.  However, this comment was found to be inaccurate and
misleading.This patch removes the TODO comment without changing any
existing behavior.

This change follows feedback from SJ who pointed out [1] that wiring-order
independence is expected and the function should simply show the last set
value.  and [2] checkpatch.pl complain about number of chars per line

No functional code changes were made.

Tested with KUnit:
- Built kernel with KUnit and DAMON sysfs tests enabled.
- Executed KUnit tests:
  ./tools/testing/kunit/kunit.py run --kunitconfig ./mm/damon/tests/
- All 25 tests passed, including damon_sysfs_test_add_targets.

Link: https://lkml.kernel.org/r/20251021215323.29734-2-swarajgaikwad1925@gmail.com
Link: https://lore.kernel.org/lkml/20251020151315.66260-1-sj@kernel.org/ [1]
Link: https://lore.kernel.org/lkml/20251021010847.68473-1-sj@kernel.org/ [2]
Signed-off-by: Swaraj Gaikwad <swarajgaikwad1925@gmail.com>
Suggested-by: SeongJae Park <sj@kernel.org>
Reviewed-by: SeongJae Park <sj@kernel.org>
Cc: David Hunter <david.hunter.linux@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-16 17:28:14 -08:00
Mehdi Ben Hadj Khelifa
f0c74b6cb9 mm/vmalloc: use kmalloc_array() instead of kmalloc()
The number of NUMA nodes (nr_node_ids) is bounded, so overflow is not a
practical concern here.  However, using kmalloc_array() better reflects
the intent to allocate an array of unsigned ints, and improves consistency
with other NUMA-related allocations.

No functional change intended.

Link: https://lkml.kernel.org/r/20251018201207.27441-1-mehdi.benhadjkhelifa@gmail.com
Signed-off-by: Mehdi Ben Hadj Khelifa <mehdi.benhadjkhelifa@gmail.com>
Reviewed-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Reviewed-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Reviewed-by: Khalid Aziz <khalid@kernel.org>
Cc: David Hunter <david.hunter.linux@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-16 17:28:14 -08:00
Bagas Sanjaya
184c753342 vmalloc: separate gfp_mask adjunctive parentheses in __vmalloc_node_noprof() kernel-doc comment
Sphinx reports htmldocs warning on __vmalloc_node() comment:

Documentation/core-api/mm-api:52: ./mm/vmalloc.c:4036: WARNING: Inline strong start-string without end-string. [docutils]

Fix it by separating adjunctive parentheses from preceding gfp_mask
formatting markup.

Link: https://lkml.kernel.org/r/20251020044933.15222-1-bagasdotme@gmail.com
Fixes: 32904ba6f5ef ("vmalloc: update __vmalloc_node_noprof() documentation")
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Closes: https://lore.kernel.org/linux-next/20251020134902.3a11107e@canb.auug.org.au/
Signed-off-by: Bagas Sanjaya <bagasdotme@gmail.com>
Reviewed-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Stehen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-16 17:28:14 -08:00
Lorenzo Stoakes
8247e2600e mm: update resctl to use mmap_prepare
Make use of the ability to specify a remap action within mmap_prepare to
update the resctl pseudo-lock to use mmap_prepare in favour of the
deprecated mmap hook.

Link: https://lkml.kernel.org/r/95b28b066f37ca25f56fa9460a9367f1a866f88b.1760959442.git.lorenzo.stoakes@oracle.com
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Acked-by: Reinette Chatre <reinette.chatre@intel.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andreas Larsson <andreas@gaisler.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Dave Martin <dave.martin@arm.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Dmitriy Vyukov <dvyukov@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Guo Ren <guoren@kernel.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: James Morse <james.morse@arm.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kevin Tian <kevin.tian@intel.com>
Cc: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Nicolas Pitre <nico@fluxnic.net>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Pedro Falcato <pfalcato@suse.de>
Cc: Robin Murohy <robin.murphy@arm.com>
Cc: Sumanth Korikkar <sumanthk@linux.ibm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: "Uladzislau Rezki (Sony)" <urezki@gmail.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-16 17:28:14 -08:00
Lorenzo Stoakes
ab04945f91 mm: update mem char driver to use mmap_prepare
Update the mem char driver (backing /dev/mem and /dev/zero) to use
f_op->mmap_prepare hook rather than the deprecated f_op->mmap.

The /dev/zero implementation has a very unique and rather concerning
characteristic in that it converts MAP_PRIVATE mmap() mappings anonymous
when they are, in fact, not.

The new f_op->mmap_prepare() can support this, but rather than introducing
a helper function to perform this hack (and risk introducing other users),
utilise the success hook to do so.

We utilise the newly introduced shmem_zero_setup_desc() to allow for the
shared mapping case via an f_op->mmap_prepare() hook.

We also use the desc->action_error_hook to filter the remap error to
-EAGAIN to keep behaviour consistent.

Link: https://lkml.kernel.org/r/48f60764d7a6901819d1af778fa33b775d2e8c77.1760959442.git.lorenzo.stoakes@oracle.com
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andreas Larsson <andreas@gaisler.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Chatre, Reinette <reinette.chatre@intel.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Dave Martin <dave.martin@arm.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Dmitriy Vyukov <dvyukov@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Guo Ren <guoren@kernel.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: James Morse <james.morse@arm.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kevin Tian <kevin.tian@intel.com>
Cc: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Nicolas Pitre <nico@fluxnic.net>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Pedro Falcato <pfalcato@suse.de>
Cc: Robin Murohy <robin.murphy@arm.com>
Cc: Sumanth Korikkar <sumanthk@linux.ibm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: "Uladzislau Rezki (Sony)" <urezki@gmail.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-16 17:28:13 -08:00
Lorenzo Stoakes
89646d9c74 mm: add shmem_zero_setup_desc()
Add the ability to set up a shared anonymous mapping based on a VMA
descriptor rather than a VMA.

This is a prerequisite for converting to the char mm driver to use the
mmap_prepare hook.

Link: https://lkml.kernel.org/r/d9181517a7e3d6b014a5697c6990d3722c2c9fcd.1760959442.git.lorenzo.stoakes@oracle.com
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andreas Larsson <andreas@gaisler.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Chatre, Reinette <reinette.chatre@intel.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Dave Martin <dave.martin@arm.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Dmitriy Vyukov <dvyukov@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Guo Ren <guoren@kernel.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: James Morse <james.morse@arm.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kevin Tian <kevin.tian@intel.com>
Cc: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Nicolas Pitre <nico@fluxnic.net>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Pedro Falcato <pfalcato@suse.de>
Cc: Robin Murohy <robin.murphy@arm.com>
Cc: Sumanth Korikkar <sumanthk@linux.ibm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: "Uladzislau Rezki (Sony)" <urezki@gmail.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-16 17:28:13 -08:00
Lorenzo Stoakes
ea52cb24cd mm/hugetlbfs: update hugetlbfs to use mmap_prepare
Since we can now perform actions after the VMA is established via
mmap_prepare, use desc->action_success_hook to set up the hugetlb lock
once the VMA is setup.

We also make changes throughout hugetlbfs to make this possible.

Note that we must hide newly established hugetlb VMAs from the rmap until
the operation is entirely complete as we establish a hugetlb lock during
VMA setup that can be raced by rmap users.

Link: https://lkml.kernel.org/r/b1afa16d3cfa585a03df9ae215ae9f905b3f0ed7.1760959442.git.lorenzo.stoakes@oracle.com
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Tested-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andreas Larsson <andreas@gaisler.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Chatre, Reinette <reinette.chatre@intel.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Dave Martin <dave.martin@arm.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Dmitriy Vyukov <dvyukov@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Guo Ren <guoren@kernel.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: James Morse <james.morse@arm.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kevin Tian <kevin.tian@intel.com>
Cc: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Nicolas Pitre <nico@fluxnic.net>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Pedro Falcato <pfalcato@suse.de>
Cc: Robin Murohy <robin.murphy@arm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: "Uladzislau Rezki (Sony)" <urezki@gmail.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-16 17:28:13 -08:00
Lorenzo Stoakes
da003453dc doc: update porting, vfs documentation for mmap_prepare actions
Now we have introduced the ability to specify that actions should be taken
after a VMA is established via the vm_area_desc->action field as specified
in mmap_prepare, update both the VFS documentation and the porting guide
to describe this.

Link: https://lkml.kernel.org/r/472ce3da7662ed1065cc299d14bffb70b1a845e7.1760959442.git.lorenzo.stoakes@oracle.com
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andreas Larsson <andreas@gaisler.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Chatre, Reinette <reinette.chatre@intel.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Dave Martin <dave.martin@arm.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Dmitriy Vyukov <dvyukov@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Guo Ren <guoren@kernel.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: James Morse <james.morse@arm.com>
Cc: Jann Horn <jannh@google.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kevin Tian <kevin.tian@intel.com>
Cc: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Nicolas Pitre <nico@fluxnic.net>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Pedro Falcato <pfalcato@suse.de>
Cc: Robin Murohy <robin.murphy@arm.com>
Cc: Sumanth Korikkar <sumanthk@linux.ibm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: "Uladzislau Rezki (Sony)" <urezki@gmail.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-16 17:28:13 -08:00
Lorenzo Stoakes
ac0a3fc9c0 mm: add ability to take further action in vm_area_desc
Some drivers/filesystems need to perform additional tasks after the VMA is
set up.  This is typically in the form of pre-population.

The forms of pre-population most likely to be performed are a PFN remap
or the insertion of normal folios and PFNs into a mixed map.

We start by implementing the PFN remap functionality, ensuring that we
perform the appropriate actions at the appropriate time - that is setting
flags at the point of .mmap_prepare, and performing the actual remap at the
point at which the VMA is fully established.

This prevents the driver from doing anything too crazy with a VMA at any
stage, and we retain complete control over how the mm functionality is
applied.

Unfortunately callers still do often require some kind of custom action,
so we add an optional success/error _hook to allow the caller to do
something after the action has succeeded or failed.

This is done at the point when the VMA has already been established, so
the harm that can be done is limited.

The error hook can be used to filter errors if necessary.

There may be cases in which the caller absolutely must hold the file rmap
lock until the operation is entirely complete. It is an edge case, but
certainly the hugetlbfs mmap hook requires it.

To accommodate this, we add the hide_from_rmap_until_complete flag to the
mmap_action type. In this case, if a new VMA is allocated, we will hold the
file rmap lock until the operation is entirely completed (including any
success/error hooks).

Note that we do not need to update __compat_vma_mmap() to accommodate this
flag, as this function will be invoked from an .mmap handler whose VMA is
not yet visible, so we implicitly hide it from the rmap.

If any error arises on these final actions, we simply unmap the VMA
altogether.

Also update the stacked filesystem compatibility layer to utilise the
action behaviour, and update the VMA tests accordingly.

While we're here, rename __compat_vma_mmap_prepare() to __compat_vma_mmap()
as we are now performing actions invoked by the mmap_prepare in addition to
just the mmap_prepare hook.

Link: https://lkml.kernel.org/r/2601199a7b2eaeadfcd8ab6e199c6d1706650c94.1760959442.git.lorenzo.stoakes@oracle.com
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andreas Larsson <andreas@gaisler.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Chatre, Reinette <reinette.chatre@intel.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Dave Martin <dave.martin@arm.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Dmitriy Vyukov <dvyukov@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Guo Ren <guoren@kernel.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: James Morse <james.morse@arm.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kevin Tian <kevin.tian@intel.com>
Cc: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Nicolas Pitre <nico@fluxnic.net>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Pedro Falcato <pfalcato@suse.de>
Cc: Robin Murohy <robin.murphy@arm.com>
Cc: Sumanth Korikkar <sumanthk@linux.ibm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: "Uladzislau Rezki (Sony)" <urezki@gmail.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-16 17:28:12 -08:00
Lorenzo Stoakes
db91b78329 mm: introduce io_remap_pfn_range_[prepare, complete]()
We introduce the io_remap*() equivalents of remap_pfn_range_prepare() and
remap_pfn_range_complete() to allow for I/O remapping via mmap_prepare.

Make these internal to mm, as they should only be used by internal helpers.

Link: https://lkml.kernel.org/r/4065134f13a24a3e14691b7443bcee7490b18a5c.1760959442.git.lorenzo.stoakes@oracle.com
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andreas Larsson <andreas@gaisler.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Chatre, Reinette <reinette.chatre@intel.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Dave Martin <dave.martin@arm.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Dmitriy Vyukov <dvyukov@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Guo Ren <guoren@kernel.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: James Morse <james.morse@arm.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kevin Tian <kevin.tian@intel.com>
Cc: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Nicolas Pitre <nico@fluxnic.net>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Pedro Falcato <pfalcato@suse.de>
Cc: Robin Murohy <robin.murphy@arm.com>
Cc: Sumanth Korikkar <sumanthk@linux.ibm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: "Uladzislau Rezki (Sony)" <urezki@gmail.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-16 17:28:12 -08:00
Lorenzo Stoakes
c707a68f94 mm: abstract io_remap_pfn_range() based on PFN
The only instances in which we customise this function are ones in which we
customise the PFN used.

Instances where architectures were not passing the pgprot value through
pgprot_decrypted() are ones where pgprot_decrypted() was a no-op anyway, so
we can simply always pass pgprot through this function.

Use this fact to simplify the use of io_remap_pfn_range(), by abstracting
the PFN via io_remap_pfn_range_pfn() and using this instead of providing a
general io_remap_pfn_range() function per-architecture.

Link: https://lkml.kernel.org/r/d086191bf431b58ce3b231b4f4f555d080f60327.1760959442.git.lorenzo.stoakes@oracle.com
Suggested-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andreas Larsson <andreas@gaisler.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Chatre, Reinette <reinette.chatre@intel.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Dave Martin <dave.martin@arm.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Dmitriy Vyukov <dvyukov@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Guo Ren <guoren@kernel.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: James Morse <james.morse@arm.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kevin Tian <kevin.tian@intel.com>
Cc: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Nicolas Pitre <nico@fluxnic.net>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Pedro Falcato <pfalcato@suse.de>
Cc: Robin Murohy <robin.murphy@arm.com>
Cc: Sumanth Korikkar <sumanthk@linux.ibm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: "Uladzislau Rezki (Sony)" <urezki@gmail.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-16 17:28:12 -08:00
Lorenzo Stoakes
51e38e7d40 mm: add remap_pfn_range_prepare(), remap_pfn_range_complete()
We need the ability to split PFN remap between updating the VMA and
performing the actual remap, in order to do away with the legacy f_op->mmap
hook.

To do so, update the PFN remap code to provide shared logic, and also make
remap_pfn_range_notrack() static, as its one user, io_mapping_map_user()
was removed in commit 9a4f90e246 ("mm: remove mm/io-mapping.c").

Then, introduce remap_pfn_range_prepare(), which accepts VMA descriptor
and PFN parameters, and remap_pfn_range_complete() which accepts the same
parameters as remap_pfn_rangte().

remap_pfn_range_prepare() will set the cow vma->vm_pgoff if necessary, so
it must be supplied with a correct PFN to do so.

While we're here, also clean up the duplicated #ifdef
__HAVE_PFNMAP_TRACKING check and put into a single #ifdef/#else block.

We keep these internal to mm as they should only be used by internal
helpers.

Link: https://lkml.kernel.org/r/75b55de63249b3aa0fd5b3b08ed1d3ff19255d0d.1760959442.git.lorenzo.stoakes@oracle.com
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Acked-by: Pedro Falcato <pfalcato@suse.de>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andreas Larsson <andreas@gaisler.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Chatre, Reinette <reinette.chatre@intel.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Dave Martin <dave.martin@arm.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Dmitriy Vyukov <dvyukov@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Guo Ren <guoren@kernel.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: James Morse <james.morse@arm.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kevin Tian <kevin.tian@intel.com>
Cc: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Nicolas Pitre <nico@fluxnic.net>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Robin Murohy <robin.murphy@arm.com>
Cc: Sumanth Korikkar <sumanthk@linux.ibm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: "Uladzislau Rezki (Sony)" <urezki@gmail.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-16 17:28:12 -08:00
Lorenzo Stoakes
2bcd9207de mm/vma: rename __mmap_prepare() function to avoid confusion
Now we have the f_op->mmap_prepare() hook, having a static function called
__mmap_prepare() that has nothing to do with it is confusing, so rename
the function to __mmap_setup().

Link: https://lkml.kernel.org/r/d25a22c60ca0f04091697ef9cda0d72ce0cf8af3.1760959442.git.lorenzo.stoakes@oracle.com
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Pedro Falcato <pfalcato@suse.de>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andreas Larsson <andreas@gaisler.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Chatre, Reinette <reinette.chatre@intel.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Dave Martin <dave.martin@arm.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Dmitriy Vyukov <dvyukov@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Guo Ren <guoren@kernel.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: James Morse <james.morse@arm.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kevin Tian <kevin.tian@intel.com>
Cc: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Nicolas Pitre <nico@fluxnic.net>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Robin Murohy <robin.murphy@arm.com>
Cc: Sumanth Korikkar <sumanthk@linux.ibm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: "Uladzislau Rezki (Sony)" <urezki@gmail.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-16 17:28:11 -08:00
Lorenzo Stoakes
651fdda840 relay: update relay to use mmap_prepare
It is relatively trivial to update this code to use the f_op->mmap_prepare
hook in favour of the deprecated f_op->mmap hook, so do so.

Link: https://lkml.kernel.org/r/7c9e82cdddf8b573ea3edb8cdb697363e3ccb5d7.1760959442.git.lorenzo.stoakes@oracle.com
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Pedro Falcato <pfalcato@suse.de>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andreas Larsson <andreas@gaisler.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Chatre, Reinette <reinette.chatre@intel.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Dave Martin <dave.martin@arm.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Dmitriy Vyukov <dvyukov@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Guo Ren <guoren@kernel.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: James Morse <james.morse@arm.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kevin Tian <kevin.tian@intel.com>
Cc: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Nicolas Pitre <nico@fluxnic.net>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Robin Murohy <robin.murphy@arm.com>
Cc: Sumanth Korikkar <sumanthk@linux.ibm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: "Uladzislau Rezki (Sony)" <urezki@gmail.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-16 17:28:11 -08:00
Lorenzo Stoakes
54c58a2f5f mm: add vma_desc_size(), vma_desc_pages() helpers
It's useful to be able to determine the size of a VMA descriptor range
used on f_op->mmap_prepare, expressed both in bytes and pages, so add
helpers for both and update code that could make use of it to do so.

Link: https://lkml.kernel.org/r/74ef338203c9ff08a9ace73a8f1f6116a79112a0.1760959442.git.lorenzo.stoakes@oracle.com
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Pedro Falcato <pfalcato@suse.de>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andreas Larsson <andreas@gaisler.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Chatre, Reinette <reinette.chatre@intel.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Dave Martin <dave.martin@arm.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Dmitriy Vyukov <dvyukov@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Guo Ren <guoren@kernel.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: James Morse <james.morse@arm.com>
Cc: Jann Horn <jannh@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kevin Tian <kevin.tian@intel.com>
Cc: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Nicolas Pitre <nico@fluxnic.net>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Robin Murohy <robin.murphy@arm.com>
Cc: Sumanth Korikkar <sumanthk@linux.ibm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: "Uladzislau Rezki (Sony)" <urezki@gmail.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-16 17:28:11 -08:00
Lorenzo Stoakes
cf1d98f44d mm/vma: remove unused function, make internal functions static
unlink_file_vma() is not used by anything, so remove it.

vma_link() and vma_link_file() are only used within mm/vma.c, so make them
static.

Link: https://lkml.kernel.org/r/f2ab9ea051225a02e6d1d45a7608f4e149220117.1760959442.git.lorenzo.stoakes@oracle.com
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andreas Larsson <andreas@gaisler.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Chatre, Reinette <reinette.chatre@intel.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Dave Martin <dave.martin@arm.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Dmitriy Vyukov <dvyukov@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Guo Ren <guoren@kernel.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: James Morse <james.morse@arm.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kevin Tian <kevin.tian@intel.com>
Cc: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Nicolas Pitre <nico@fluxnic.net>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Pedro Falcato <pfalcato@suse.de>
Cc: Robin Murohy <robin.murphy@arm.com>
Cc: Sumanth Korikkar <sumanthk@linux.ibm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: "Uladzislau Rezki (Sony)" <urezki@gmail.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-16 17:28:10 -08:00
Lorenzo Stoakes
8e18a7f435 device/dax: update devdax to use mmap_prepare
The devdax driver does nothing special in its f_op->mmap hook, so
straightforwardly update it to use the mmap_prepare hook instead.

Link: https://lkml.kernel.org/r/1e8665d052ac8cf2f7ff92b6c7862614f7fd306c.1760959442.git.lorenzo.stoakes@oracle.com
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Acked-by: Pedro Falcato <pfalcato@suse.de>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andreas Larsson <andreas@gaisler.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Chatre, Reinette <reinette.chatre@intel.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Dave Martin <dave.martin@arm.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Dmitriy Vyukov <dvyukov@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Guo Ren <guoren@kernel.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: James Morse <james.morse@arm.com>
Cc: Jann Horn <jannh@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kevin Tian <kevin.tian@intel.com>
Cc: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Nicolas Pitre <nico@fluxnic.net>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Robin Murohy <robin.murphy@arm.com>
Cc: Sumanth Korikkar <sumanthk@linux.ibm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: "Uladzislau Rezki (Sony)" <urezki@gmail.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-16 17:28:10 -08:00
Lorenzo Stoakes
ab3c8e7b86 mm/shmem: update shmem to use mmap_prepare
Patch series "expand mmap_prepare functionality, port more users", v5.

Since commit c84bf6dd2b ("mm: introduce new .mmap_prepare() file
callback"), The f_op->mmap hook has been deprecated in favour of
f_op->mmap_prepare.

This was introduced in order to make it possible for us to eventually
eliminate the f_op->mmap hook which is highly problematic as it allows
drivers and filesystems raw access to a VMA which is not yet correctly
initialised.

This hook also introduced complexity for the memory mapping operation, as
we must correctly unwind what we do should an error arises.

Overall this interface being so open has caused significant problems for
us, including security issues, it is important for us to simply eliminate
this as a source of problems.

Therefore this series continues what was established by extending the
functionality further to permit more drivers and filesystems to use
mmap_prepare.

We start by udpating some existing users who can use the mmap_prepare
functionality as-is.

We then introduce the concept of an mmap 'action', which a user, on
mmap_prepare, can request to be performed upon the VMA:

* Nothing - default, we're done
* Remap PFN - perform PFN remap with specified parameters
* I/O remap PFN - perform I/O PFN remap with specified parameters

By setting the action in mmap_prepare, this allows us to dynamically
decide what to do next, so if a driver/filesystem needs to determine
whether to e.g.  remap or use a mixed map, it can do so then change which
is done.

This significantly expands the capabilities of the mmap_prepare hook,
while maintaining as much control as possible in the mm logic.

We split [io_]remap_pfn_range*() functions which allow for PFN remap (a
typical mapping prepopulation operation) split between a prepare/complete
step, as well as io_mremap_pfn_range_prepare, complete for a similar
purpose.

From there we update various mm-adjacent logic to use this functionality
as a first set of changes.

We also add success and error hooks for post-action processing for e.g. 
output debug log on success and filtering error codes.


This patch (of 15):

This simply assigns the vm_ops so is easily updated - do so.

Link: https://lkml.kernel.org/r/cover.1760959441.git.lorenzo.stoakes@oracle.com
Link: https://lkml.kernel.org/r/7b93b1e89028e39507dac5ca01991e1374d5bbe8.1760959442.git.lorenzo.stoakes@oracle.com
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Pedro Falcato <pfalcato@suse.de>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andreas Larsson <andreas@gaisler.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Baoquan He <bhe@redhat.com>
Cc: Chatre, Reinette <reinette.chatre@intel.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Dave Martin <dave.martin@arm.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Dmitriy Vyukov <dvyukov@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Guo Ren <guoren@kernel.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: James Morse <james.morse@arm.com>
Cc: Jann Horn <jannh@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kevin Tian <kevin.tian@intel.com>
Cc: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Nicolas Pitre <nico@fluxnic.net>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Robin Murohy <robin.murphy@arm.com>
Cc: Sumanth Korikkar <sumanthk@linux.ibm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: "Uladzislau Rezki (Sony)" <urezki@gmail.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-16 17:28:10 -08:00
Quanmin Yan
dfc02531f4 mm/damon/reclaim: use min_sz_region for core address alignment when setting regions
When setting regions in DAMON_RECLAIM, DAMON_MIN_REGION will be applied as
the core address alignment, and the monitoring target address ranges would
be aligned on DAMON_MIN_REGION * addr_unit.  When users 1) set addr_unit
to a value larger than 1, and 2) set the monitoring target address range
as not aligned on DAMON_MIN_REGION * addr_unit, it will cause
DAMON_RECLAIM to operate on unexpectedly large physical address ranges.

For example, if the user sets the monitoring target address range to [4,
8) and addr_unit as 1024, the aimed monitoring target address range is [4
KiB, 8 KiB).  Assuming DAMON_MIN_REGION is 4096, so resulting target
address range will be [0, 4096) in the DAMON core layer address system,
and [0, 4 MiB) in the physical address space, which is an unexpected
range.

To fix the issue, use min_sz_region for core address alignment when
setting regions.

Link: https://lkml.kernel.org/r/20251020130125.2875164-3-yanquanmin1@huawei.com
Fixes: 7db551fcfb ("mm/damon/reclaim: support addr_unit for DAMON_RECLAIM")
Signed-off-by: Quanmin Yan <yanquanmin1@huawei.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: ze zuo <zuoze1@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-16 17:28:10 -08:00
Quanmin Yan
e859a224fa mm/damon: add a min_sz_region parameter to damon_set_region_biggest_system_ram_default()
Patch series "mm/damon: fixes for address alignment issues in
DAMON_LRU_SORT and DAMON_RECLAIM", v2.

In DAMON_LRU_SORT and DAMON_RECLAIM, damon_set_regions() will apply
DAMON_MIN_REGION as the core address alignment, and the monitoring target
address ranges would be aligned on DAMON_MIN_REGION * addr_unit.  When
users 1) set addr_unit to a value larger than 1, and 2) set the monitoring
target address range as not aligned on DAMON_MIN_REGION * addr_unit, it
will cause DAMON_LRU_SORT and DAMON_RECLAIM to operate on unexpectedly
large physical address ranges.

For example, if the user sets the monitoring target address range to [4,
8) and addr_unit as 1024, the aimed monitoring target address range is [4
KiB, 8 KiB).  Assuming DAMON_MIN_REGION is 4096, so resulting target
address range will be [0, 4096) in the DAMON core layer address system,
and [0, 4 MiB) in the physical address space, which is an unexpected
range.

To fix the issue, add a min_sz_region parameter to
damon_set_region_biggest_system_ram_default() and use it when calling
damon_set_regions(), replacing the direct use of DAMON_MIN_REGION.


This patch (of 2):

In DAMON_LRU_SORT, damon_set_regions() will apply DAMON_MIN_REGION as the
core address alignment, and the monitoring target address ranges would be
aligned on DAMON_MIN_REGION * addr_unit.  When users 1) set addr_unit to a
value larger than 1, and 2) set the monitoring target address range as not
aligned on DAMON_MIN_REGION * addr_unit, it will cause DAMON_LRU_SORT to
operate on unexpectedly large physical address ranges.

For example, if the user sets the monitoring target address range to [4,
8) and addr_unit as 1024, the aimed monitoring target address range is [4
KiB, 8 KiB).  Assuming DAMON_MIN_REGION is 4096, so resulting target
address range will be [0, 4096) in the DAMON core layer address system,
and [0, 4 MiB) in the physical address space, which is an unexpected
range.

To fix the issue, add a min_sz_region parameter to
damon_set_region_biggest_system_ram_default() and use it when calling
damon_set_regions(), replacing the direct use of DAMON_MIN_REGION.

Link: https://lkml.kernel.org/r/20251020130125.2875164-1-yanquanmin1@huawei.com
Link: https://lkml.kernel.org/r/20251020130125.2875164-2-yanquanmin1@huawei.com
Fixes: 2e0fe9245d ("mm/damon/lru_sort: support addr_unit for DAMON_LRU_SORT")
Signed-off-by: Quanmin Yan <yanquanmin1@huawei.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: ze zuo <zuoze1@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-16 17:28:09 -08:00
Lance Yang
074f027d15 mm/khugepaged: guard is_zero_pfn() calls with pte_present()
A non-present entry, like a swap PTE, contains completely different data
(swap type and offset).  pte_pfn() doesn't know this, so if we feed it a
non-present entry, it will spit out a junk PFN.

What if that junk PFN happens to match the zeropage's PFN by sheer chance?
While really unlikely, this would be really bad if it did.

So, let's fix this potential bug by ensuring all calls to is_zero_pfn() in
khugepaged.c are properly guarded by a pte_present() check.

Link: https://lkml.kernel.org/r/20251020151111.53561-1-lance.yang@linux.dev
Signed-off-by: Lance Yang <lance.yang@linux.dev>
Suggested-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reviewed-by: Nico Pache <npache@redhat.com>
Reviewed-by: Dev Jain <dev.jain@arm.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: Wei Yang <richard.weiyang@gmail.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-16 17:28:09 -08:00
SeongJae Park
40d923acfa Docs/ABI/damon: document DAMOS quota goal path file
A DAMON sysfs interface file for DAMOS quota goal's optional path argument
has been added.  Document it on the ABI doc.

Link: https://lkml.kernel.org/r/20251017212706.183502-11-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-16 17:28:09 -08:00
SeongJae Park
87b8351580 Docs/admin-guide/mm/damon/usage: document DAMOS quota goal path file
A new DAMON sysfs interface file, namely 'path' has been added under DAMOS
quota goal directory, for specifying the cgroup for
DAMOS_QUOTA_NODE_MEMCG_{USED,FREE}_BP metrics.  Document it on the usage
document.

Link: https://lkml.kernel.org/r/20251017212706.183502-10-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-16 17:28:09 -08:00
SeongJae Park
4cc00d41c6 Docs/mm/damon/design: document DAMOS_QUOTA_NODE_MEMCG_{USED,FREE}_BP
Update design doc for the newly added two DAMOS quota auto-tuning target
goal metrics, DAMOS_QUOTA_NODE_MEMCG_{USED,FREE}_BP.

Link: https://lkml.kernel.org/r/20251017212706.183502-9-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-16 17:28:08 -08:00
SeongJae Park
c2fbf2da4c mm/damon/sysfs-schemes: support DAMOS_QUOTA_NODE_MEMCG_FREE_BP
Extend DAMON sysfs to support DAMOS_QUOTA_NODE_MEMCG_FREE_BP.

Link: https://lkml.kernel.org/r/20251017212706.183502-8-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-16 17:28:08 -08:00
SeongJae Park
98fdce76fb mm/damon/core: add DAMOS quota gaol metric for per-memcg per-numa free memory
Add a variant of DAMOS_QUOTA_NODE_MEMCG_USED_BP, for the free memory
portion.  The value of the metric is implemented as the entire memory of
the given NUMA node subtracted by the given cgroup's usage.  So from a
perspective, "unused" could be a better term than "free".  But arguably it
is not very clear what is better, so use the term "free".

Link: https://lkml.kernel.org/r/20251017212706.183502-7-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-16 17:28:08 -08:00
SeongJae Park
a1d1df78ac mm/damon/sysfs-schemes: support DAMOS_QUOTA_NODE_MEMCG_USED_BP
Add support of DAMOS_QUOTA_NODE_MEMCG_USED_BP.  For this, extend quota
goal metric inputs for the new metric, and update DAMOS core layer request
construction logic to set the target cgroup, which is specified by the
user, via the 'path' file.

Link: https://lkml.kernel.org/r/20251017212706.183502-6-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-16 17:28:08 -08:00
SeongJae Park
c41e253a41 mm/damon/sysfs-schemes: implement path file under quota goal directory
Add a DAMOS sysfs file for specifying the cgroup of the interest for
DAMOS_QUOTA_NODE_MEMCG_USED_BP.

Link: https://lkml.kernel.org/r/20251017212706.183502-5-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-16 17:28:07 -08:00
SeongJae Park
b74a120bcf mm/damon/core: implement DAMOS_QUOTA_NODE_MEMCG_USED_BP
Implement the handling of the new DAMOS quota goal metric for per-memcg
per-node memory usage, namely DAMOS_QUOTA_NODE_MEMCG_USED_BP.  The metric
value is calculated as the sum of active/inactive anon/file pages of the
given cgroup for a given NUMA node.

Link: https://lkml.kernel.org/r/20251017212706.183502-4-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-16 17:28:07 -08:00
SeongJae Park
6a18bbe483 mm/damon: add DAMOS quota goal type for per-memcg per-node memory usage
Define a new DAMOS quota auto-tuning target metric for per-cgroup per-node
memory usage.  For specifying the cgroup of the interest, add a field,
namely memcg_id, to damos_quota_goal struct.

Note that this commit is only implementing the interface.  The handling of
the interface (the metric value calculation) will be implemented in the
following commit.

Link: https://lkml.kernel.org/r/20251017212706.183502-3-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-16 17:28:07 -08:00
SeongJae Park
d3946c5f4c mm/damon: document damos_quota_goal->nid use case
Patch series "mm/damon: allow DAMOS auto-tuned for per-memcg per-node
memory usage".

Introduce two new DAMOS quota auto-tuning target metrics for per-cgroup
per-NUMA node memory utilization.  Expected use cases are cgroup level
access-aware NUMA memory managements, such as memory tiering or proactive
reclamation on cgroup-based multi-tenant NUMA systems.

Background
==========

The aim-oriented aggressiveness auto-tuning feature of DAMOS is a highly
recommended way for modern DAMOS use cases.  Using it, users can specify
what system status they want to achieve with what access-aware system
operations.  For example, reclaim cold memory aiming for 0.5 percent of
memory pressure (proactive reclaim), or migrate hot and cold memory
between NUMA nodes having different speed (memory tiering).  Then DAMOS
automatically adjusts the aggressiveness of the system operation (e.g.,
increase/decrease reclaim target coldness threshold) based on current
status of the system.

The use case is limited by the supported system status metrics for
specifying the target system status.  Two new system metrics for per-node
memory usage ratio, namely DAMOS_QUOTA_NODE_MEM_{USED,FREE}_BP, were
recently added to extend the use cases for access-aware NUMA nodes
management, such as memory tiering.  Those are expected to be useful for
not only memory tiering but also general access-aware inter-NUMA node page
migration, though.

Limitation
----------

The per-node memory usage based auto-tuning can be applied only
system-wide.  For cgroups-based multi-tenant systems, it could arguably
harm the fairness.  For example, a cgroup may use faster NUMA node memory
more than other cgroup, depending on their access pattern.  If the user of
each cgroup are promised to get the same quality and amount of the system
resource, this can arguably be an unfair situation.

DAMOS supports cgroup level system operations via DAMOS filter.  But the
quota auto-tuning system is not aware of cgroups.

New DAMOS Quota Tuning Metrics for Per-Cgroup Per-NUMA Memory Usage
===================================================================

To overcome the limitation, introduce two new DAMOS quota auto-tuning goal
metrics, namely DAMOS_QUOTA_NODE_MEMCG_{USED,FREE}_BP.  Those can be
thought of as a variant of DAMOS_QUOTA_NODE_MEM_{USED,FREE}_BP that
extended for cgroups.

The two metrics specifies per-cgroup, per-node amount of used and unused
memory in ratio to the total memory of the node.  For example, let's
assume a system has two NUMA nodes of size 100 GiB and 50 GiB.  And two
cgroups are using 40 GiB and 60 GiB of node 0, 20 GiB and 10 GiB of node
1, respectively, as illustrated by the below table.

                     node-0    node-1
    Total memory     100 GiB   50 GiB
    Cgroup A usage   40 GiB    20 GiB
    Cgroup B usage   60 GiB    10 GiB

Then, DAMOS_QUOTA_NODE_MEMCG_USED_BP for the cgroups for the first node
are, 40 GiB / 100 GiB = 4,000 bp (40 percent) and 60 GiB / 100 GiB = 6,000
bp (60 percent), respectively.  Those for the second node are, 20 GiB / 50
GiB = 4000 bp (40 percent) and 10 GiB / 50 GiB = 2000 bp (20 percent),
respectively.

DAMOS_QUOTA_NODE_MEMCG_FREE_BP for the four cases are, 60 GiB /100 GiB =
6000 bp, 40 GiB / 100 GiB = 4000 bp, 30 GiB / 50 GiB = 6000 bp, and 40 GiB
/ 50 GiB = 8000 bp, respectively.

    DAMOS_QUOTA_NODE_MEMCG_USED_BP for cgroup A node-0: 4000 bp
    DAMOS_QUOTA_NODE_MEMCG_USED_BP for cgroup B node-0: 6000 bp
    DAMOS_QUOTA_NODE_MEMCG_USED_BP for cgroup A node-1: 4000 bp
    DAMOS_QUOTA_NODE_MEMCG_USED_BP for cgroup B node-1: 2000 bp

    DAMOS_QUOTA_NODE_MEMCG_FREE_BP for cgroup A node-0: 6000 bp
    DAMOS_QUOTA_NODE_MEMCG_FREE_BP for cgroup B node-0: 4000 bp
    DAMOS_QUOTA_NODE_MEMCG_FREE_BP for cgroup A node-1: 6000 bp
    DAMOS_QUOTA_NODE_MEMCG_FREE_BP for cgroup B node-1: 8000 bp

Using these, users can specify how much [un]used amount of memory for
per-cgroup and per-node DAMOS should make as a result of the auto-tuning.

Example Usecase: Cgroup Level Memory Tiering
============================================

Let's suppose a typical and simple tiered memory system.  The system
equips two NUMA nodes.  The first node (node 0) is CPU-attached and fast. 
The second node (node 1) is CPU-unattached and slow.  It runs two cgroups
that desire to use about 30 percent and 70 percent of the faster node as
much as possible for their hot data, respectively.  Then, the user can
implement DAMOS-based memory tiering for the system using the DAMON
user-space tool (damo), like below.

    # ./damo start \
    	`# kdamond for node 1 (slow)` \
        --numa_node 1 --monitoring_intervals_goal 4% 3 5ms 10s \
	    `# promotion scheme for cgroup a` \
            --damos_action migrate_hot 0 --damos_access_rate 5% max \
            --damos_apply_interval 1s \
	    --damos_filter allow memcg /workloads/a \
            --damos_filter allow young \
            --damos_quota_interval 1s --damos_quota_space 200MB \
            --damos_quota_goal node_memcg_used_bp 29.7% 0 /workloads/a \
	    \
	    `# promotion scheme for cgroup b` \
            --damos_action migrate_hot 0 --damos_access_rate 5% max \
            --damos_apply_interval 1s \
	    --damos_filter allow memcg /workloads/b \
            --damos_filter allow young \
            --damos_quota_interval 1s --damos_quota_space 200MB \
            --damos_quota_goal node_memcg_used_bp 69.7% 0 workloads/b \
	    \
    	`# kdamond for node 0 (fast)` \
        --numa_node 0 --monitoring_intervals_goal 4% 3 5ms 10s \
            `# demotion scheme for cgroup a` \
            --damos_action migrate_cold 1 --damos_access_rate 0% 0% \
            --damos_apply_interval 1s \
	    --damos_filter allow memcg /workloads/a \
            --damos_filter reject young \
            --damos_quota_interval 1s --damos_quota_space 200MB \
            --damos_quota_goal node_memcg_free_bp 70.5% 0 \
	    \
            `# demotion scheme for cgroup b` \
            --damos_action migrate_cold 1 --damos_access_rate 0% 0% \
            --damos_apply_interval 1s \
	    --damos_filter allow memcg /workloads/a \
            --damos_filter reject young \
            --damos_quota_interval 1s --damos_quota_space 200MB \
            --damos_quota_goal node_memcg_free_bp 30.5% 0 \
	    \
            --damos_nr_quota_goals 1 1 1 1 --damos_nr_filters 1 1 1 1 \
        --nr_targets 1 1 --nr_schemes 2 2 --nr_ctxs 1 1

With the command, the user-space tool will ask DAMON to spawn two kernel
threads, each for monitoring accesses to node 1 (slow) and node 0 (fast),
respectively.  It installs two DAMOS schemes on each thread.  Let's call
them "promotion scheme for cgroup a/b", and "demotion scheme for cgroup
a/b" in the order.  The promotion schemes are installed on the DAMON
thread for node 1 (slow), and demotion schemes are installed on the DAMON
thread for node 0 (fast).

Cgroup Level Hot Pages Migration (Promotion)
--------------------------------------------

Promotion schemes will find memory regions on node 1 (slow), that some
access was detected.  The schemes will then migrate the found memory to
node 0 (fast), hottest pages first.

For accurate and effective migration, these schemes use two page level
filters.  First, the migration will be filtered for only cgroup A and
cgroup B.  That is, "promotion scheme for cgroup B" will not do the
migration if the page is for cgroup A.  Secondly, the schemes will ignore
pages that having their page table's Accessed bits unset.  The per-page
Accessed bit check logic will also unset the bit if it was set, for the
next check.

For controlled amounts of system resource consumption and aiming on the
target memory usage, the schemes use quotas setup.  The migration is
limited to be done only up to 200 MiB per second, to limit the peak system
resource usage.  And DAMOS_QUOTA_NODE_MEMCG_USED_BP target is set for
29.7% and 69.7% of node 0 (fast), respectively.  The target value is lower
than the high level goal (30% and 70% system memory), to give headroom on
node 0 (fast).  DAMOS will adjust the speed of the pages migration based
on the target and current per-cgroup node 0 memory usage.  For example, if
cgroup A is utilizing only 10% of node 0, DAMOS will try to migrate more
of cgroup A hot pages from node 1 to node 0, up to 200 MiB per second.  If
cgroup A utilizes more than 29.7% of node 0 memory, the cgroup A hot pages
migration from node 1 to node 0 will be slowed and eventually stopped.

Cgroup Level Cold Pages Migration (Demotion)
--------------------------------------------

Demotion schemes are similar to promotion schemes, but differ in filtering
setup and quota tuning setup.  Those filter out pages having their page
table Accessed bits set.  And set 70.5% and 30.5% of node 0 memory free
rate for the cgroup A and B, respectively.  Hence, if promotion schemes or
something made cgroup A and/or B uses more than 29.5% and 69.5% of node 0,
demotion schemes will start migrating cold pages of appropriate cgroups in
node 0 to node 1, under the 200 MiB per second speed cap, while adjusting
the speed based on how much more than wanted memory is being used.

The quota target values are set to overlap with promotion targets, to keep
a minimum level of page exchanges between the nodes.  This is to avoid a
case that the target memory utilization is met, and then access pattern
changes (pages in node 1 become hotter than pages in node 0) while the
memory utilization is unchanged.  Without the overlap, neither promotion
of hotter pages in node 1, nor demotion of colder pages in node 0 will
happen since both goals are met.  As a result, the faster and slower node
will unexpectedly serve cold and hot data.

Test: Per-cgroup Memory Tiering
===============================

I ran a simplified cgroup level memory tiering using the feature, and
confirmed it works as intended.

Setup
-----

I configured a QEMU virtual machine representing a simplified version of
the system that described on the above cgroup level memory tiering example
use case.  The system equips 40 CPU cores and two NUMA nodes each having
30 GiB physical memory.  The first node (node 0) represents the faster
NUMA node, and the second node (node 1) represents the slower NUMA node. 
In specific, below qemu command line options are used.

    [...]
    -object memory-backend-ram,size=30G,id=m0 \
    -object memory-backend-ram,size=30G,id=m1 \
    -numa node,cpus=0-39,memdev=m0 \
    -numa node,memdev=m1 \
    [...]

I booted the virtual machine with a kernel that this patch series is
applied.  On the virtual machine, I created two cgroups, namely workload_a
and workload_b.  And ran a test program in each cgroup, resulting in one
process per cgroup.  The test program allocates 10 GiB memory and evenly
split it into 10 regions.  After the allocation, it repeatedly access the
first region for one minute, than the second one for one minute, and so
on.  After the one minute repeated access for the 10-th region is done, it
repeats the access from the first region.  So the process has 10 GiB of
data in total, but only 1 GiB of it is hot at a given moment, and the hot
data is gradually changed.

While the processes are running, run DAMON for a simple access-aware
memory tiering using below script.  It migrates hot and cold data of the
cgroups into node 0 and node 1, aiming the first and the second cgroups
(workload_a and workload_b, respectively) utilizing about 9.7 percent and
19.7 percent of node 0, respectively.

Note that this setup is a simplified version of the above example use
case, for ease of test.  Also note that we assigned 30 GiB physical memory
to node 0, but DAMON in this setup works for only 27 GiB of the memory. 
It is due to an internal implementation detail of DAMON user-space tool
that not really important for this test.

    #!/bin/bash
    damo start \
        --numa_node 1 \
            --damos_action migrate_hot 0 --damos_access_rate 5% max \
                --damos_apply_interval 1s \
                --damos_filter allow memcg /workload_a \
                --damos_filter allow young \
                --damos_quota_interval 1s \
                --damos_quota_goal node_memcg_used_bp 9.7% 0 /workload_a \
            --damos_action migrate_hot 0 --damos_access_rate 5% max \
                --damos_apply_interval 1s \
                --damos_filter allow memcg /workload_b \
                --damos_filter allow young \
                --damos_quota_interval 1s \
                --damos_quota_goal node_memcg_used_bp 19.7% 0 /workload_b \
        --numa_node 0 \
            --damos_action migrate_cold 1 --damos_access_rate 0% 0% \
                --damos_apply_interval 1s \
                --damos_filter allow memcg /workload_a \
                --damos_filter reject young \
                --damos_quota_interval 1s \
                --damos_quota_goal node_memcg_free_bp 90.5% 0 /workload_a \
            --damos_action migrate_cold 1 --damos_access_rate 0% 0% \
                --damos_apply_interval 1s \
                --damos_filter allow memcg /workload_b \
                --damos_filter reject young \
                --damos_quota_interval 1s \
                --damos_quota_goal node_memcg_free_bp 80.5% 0 /workload_b \
                --damos_nr_quota_goals 1 1 1 1 --damos_nr_filters 2 2 2 2 \
        --nr_targets 1 1 --nr_schemes 2 2 --nr_ctxs 1 1

After starting DAMON, the pages continuously be migrated across nodes.  A
few minutes later, the memory usage of the cgroups converges into the
aimed amounts, and keeps the level, as expected.  To confirm the status is
kept in the target level as expected, I collected the memory usage stat of
the cgroups using memory.numa_stat file, after the stats are converged.  I
repeat the stat collection 42 times with 5 seconds delay between each of
the collections.  The results are as below:

    node0_memory_usage  average  stdev
    workload_a          2.79GiB  522.06MiB
    workload_b          5.15GiB  739.10MiB

The average values are quite close to the targeted values: 27 GiB * 9.7% =
2.619 GiB for workload_a, and 27 GiB * 19.7% = 5.319 GiB.  A level of
variances are expected, given the overlap of the promotion/demotion
targets, and dynamic data access pattern of the workloads.  Give that, the
measured variances are at a reasonable level.

Patches Sequence
================

The first patch (patch 1) updates the kernel-doc comment of
damos_quota_goal struct to clarify usage of optional fields of the struct,
since later patches will add such optional fields.

Following four patches (patches 2-5) implement a new DAMOS quota goal
metric for per-cgroup per-node memory usage.  Those extends the core layer
interface for the new metric (patch 2), implement the metric value
calculation on the core layer (patch 3), add DAMON sysfs interface file
for the target cgroup specification (patch 4), and implement support of
the new metric on DAMON sysfs interface (patch 5).

Next two patches implment the second new DAMOS quota goal metric for
per-cgroup per-node free (or, unused) memory.  Those implement it in the
core layer (patch 6) and DAMON sysfs interface (patch 7), extending the
existing implementation for memory usage metric.

Final three patches update the design (patch 8), the usage (patch 9), and
the ABI (patch 10) documents for the changes that are introduced by this
patch series.


This patch (of 10):

damos_quota_goal kerneldoc comment is not explaining when @metric is used.
Update the comment for that.

Link: https://lkml.kernel.org/r/20251017212706.183502-1-sj@kernel.org
Link: https://lkml.kernel.org/r/20251017212706.183502-2-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-16 17:28:07 -08:00
Baolin Wang
2f05435df9 mm: vmscan: simplify the logic for activating dirty file folios
After commit 6b0dfabb35 ("fs: Remove aops->writepage"), we no longer
attempt to write back filesystem folios through reclaim.

However, in the shrink_folio_list() function, there still remains some
logic related to writeback control of dirty file folios.  The original
logic was that, for direct reclaim, or when folio_test_reclaim() is false,
or the PGDAT_DIRTY flag is not set, the dirty file folios would be
directly activated to avoid being scanned again; otherwise, it will try to
writeback the dirty file folios.  However, since we can no longer perform
writeback on dirty folios, the dirty file folios will still be activated.

Additionally, under the original logic, if we continue to try writeback
dirty file folios, we will also check the references flag,
sc->may_writepage, and may_enter_fs(), which may result in dirty file
folios being left in the inactive list.  This is unreasonable.  Even if
these dirty folios are scanned again, we still cannot clean them.

Therefore, the checks on these dirty file folios appear to be redundant
and can be removed.  Dirty file folios should be directly moved to the
active list to avoid being scanned again.  Since we set the PG_reclaim
flag for the dirty folios, once the writeback is completed, they will be
moved back to the tail of the inactive list to be retried for quick
reclaim.

Link: https://lkml.kernel.org/r/ba5c49955fd93c6850bcc19abf0e02e1573768aa.1760687075.git.baolin.wang@linux.alibaba.com
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-16 17:28:06 -08:00
Baolin Wang
b34619af9c mm: vmscan: filter out the dirty file folios for node_reclaim()
Patch series "optimize the logic for handling dirty file folios during
reclaim", v2.

Since we no longer attempt to write back filesystem folios during reclaim,
some logic for handling dirty file folios in the reclaim process also
needs to be updated.  Please check the details in each patch.  


This patch (of 2):

After commit 6b0dfabb35 ("fs: Remove aops->writepage"), we no longer
attempt to write back filesystem folios in pageout(), and only tmpfs/shmem
folios and anonymous swapcache folios can be written back.  Therefore, we
should also filter out the dirty filesystem folios for node_reclaim() to
avoid unnecessary LRU scans.

Link: https://lkml.kernel.org/r/cover.1760687075.git.baolin.wang@linux.alibaba.com
Link: https://lkml.kernel.org/r/c91f5ecc5152b647904c7503618a01885d913928.1760687075.git.baolin.wang@linux.alibaba.com
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-16 17:28:06 -08:00
Ye Liu
5bf65d4a8d tools/mm/page_owner_sort: add help option support
Add -h/--help option to display usage information and improve code style.

Link: https://lkml.kernel.org/r/20251016054927.138510-1-ye.liu@linux.dev
Signed-off-by: Ye Liu <liuye@kylinos.cn>
Cc: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-16 17:28:06 -08:00
Shakeel Butt
d929525c2e memcg: net: track network throttling due to memcg memory pressure
The kernel can throttle network sockets if the memory cgroup associated
with the corresponding socket is under memory pressure.  The throttling
actions include clamping the transmit window, failing to expand receive or
send buffers, aggressively prune out-of-order receive queue, FIN deferred
to a retransmitted packet and more.  Let's add memcg metric to track such
throttling actions.

At the moment memcg memory pressure is defined through vmpressure and in
future it may be defined using PSI or we may add more flexible way for the
users to define memory pressure, maybe through ebpf.  However the
potential throttling actions will remain the same, so this newly
introduced metric will continue to track throttling actions irrespective
of how memcg memory pressure is defined.

Link: https://lkml.kernel.org/r/20251016161035.86161-1-shakeel.butt@linux.dev
Signed-off-by: Shakeel Butt <shakeel.butt@linux.dev>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: Daniel Sedlak <daniel.sedlak@cdn77.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Jakub Kacinski <kuba@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Neal Cardwell <ncardwell@google.com>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: Simon Horman <horms@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Willem de Bruijn <willemb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-16 17:28:06 -08:00
wang lian
a059ad48b4 mm/khugepaged: fix comment for default scan sleep duration
The comment for khugepaged_scan_sleep_millisecs incorrectly states the
default scan period is 30 seconds.  The actual default value in the code
is 10000ms (10 seconds).

This patch corrects the comment to match the code, preventing potential
confusion.  The incorrect comment has existed since the feature was first
introduced.  While at it, replace the magic value 512 by HPAGE_PMD_NR and
use 'ptes'.

Link: https://lkml.kernel.org/r/20251015092957.37432-1-lianux.mm@gmail.com
Signed-off-by: wang lian <lianux.mm@gmail.com>
Suggested-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Dev Jain <dev.jain@arm.com>
Reviewed-by: Wei Yang <richard.weiyang@gmail.com>
Reviewed-by: Lance Yang <lance.yang@linux.dev>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Reviewed-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Acked-by: Nico Pache <npache@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-16 17:28:05 -08:00
Ye Liu
2f79ddb64b tools/mm: use <stdbool.h> in page_owner_sort.c
Use standard <stdbool.h> instead of manually defining bool, true and false.

Link: https://lkml.kernel.org/r/20251015093851.109663-1-ye.liu@linux.dev
Signed-off-by: Ye Liu <liuye@kylinos.cn>
Reviewed-by: Dev Jain <dev.jain@arm.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-16 17:28:05 -08:00
Vlastimil Babka
0f21b91101 mm/page_alloc: simplify and cleanup pcp locking
The pcp locking relies on pcp_spin_trylock() which has to be used together
with pcp_trylock_prepare()/pcp_trylock_finish() to work properly on !SMP
!RT configs.  This is tedious and error-prone.

We can remove pcp_spin_lock() and underlying pcpu_spin_lock() because we
don't use it.  Afterwards pcp_spin_unlock() is only used together with
pcp_spin_trylock().  Therefore we can add the UP_flags parameter to them
both and handle pcp_trylock_prepare()/finish() within.

Additionally for the configs where pcp_trylock_prepare()/finish() are
no-op (SMP || RT) make them pass &UP_flags to a no-op inline function. 
This ensures typechecking and makes the local variable "used" so we can
remove the __maybe_unused attributes.

In my compile testing, bloat-o-meter reported no change on SMP config, so
the compiler is capable of optimizing away the no-ops same as before, and
we have simplified the code using pcp_spin_trylock().

Link: https://lkml.kernel.org/r/20251015-b4-pcp-lock-cleanup-v2-1-740d999595d5@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Joshua Hahn <joshua.hahnjy@gmail.com>
Reviewed-by: Suren Baghdasaryan <surenb@google.com>
Cc: Brendan Jackman <jackmanb@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-16 17:28:05 -08:00
Joshua Hahn
91e6912966 mm/page_alloc: batch page freeing in free_frozen_page_commit
Before returning, free_frozen_page_commit calls free_pcppages_bulk using
nr_pcp_free to determine how many pages can appropritately be freed, based
on the tunable parameters stored in pcp.  While this number is an accurate
representation of how many pages should be freed in total, it is not an
appropriate number of pages to free at once using free_pcppages_bulk,
since we have seen the value consistently go above 2000 in the Meta fleet
on larger machines.

As such, perform batched page freeing in free_pcppages_bulk by using
pcp->batch.  In order to ensure that other processes are not starved of
the zone lock, free both the zone lock and pcp lock to yield to other
threads.

Note that because free_frozen_page_commit now performs a spinlock inside
the function (and can fail), the function may now return with a freed pcp.
To handle this, return true if the pcp is locked on exit and false
otherwise.

In addition, since free_frozen_page_commit must now be aware of what UP
flags were stored at the time of the spin lock, and because we must be
able to report new UP flags to the callers, add a new unsigned long*
parameter UP_flags to keep track of this.

The following are a few synthetic benchmarks, made on three machines.  The
first is a large machine with 754GiB memory and 316 processors.  The
second is a relatively smaller machine with 251GiB memory and 176
processors.  The third and final is the smallest of the three, which has
62GiB memory and 36 processors.

On all machines, I kick off a kernel build with -j$(nproc).  Negative
delta is better (faster compilation)

Large machine (754GiB memory, 316 processors)
make -j$(nproc)
+------------+---------------+-----------+
| Metric (s) | Variation (%) | Delta(%)  |
+------------+---------------+-----------+
| real       |        0.8070 |  - 1.4865 |
| user       |        0.2823 |  + 0.4081 |
| sys        |        5.0267 |  -11.8737 |
+------------+---------------+-----------+

Medium machine (251GiB memory, 176 processors)
make -j$(nproc)
+------------+---------------+----------+
| Metric (s) | Variation (%) | Delta(%) |
+------------+---------------+----------+
| real       |        0.2806 |  +0.0351 |
| user       |        0.0994 |  +0.3170 |
| sys        |        0.6229 |  -0.6277 |
+------------+---------------+----------+

Small machine (62GiB memory, 36 processors)
make -j$(nproc)
+------------+---------------+----------+
| Metric (s) | Variation (%) | Delta(%) |
+------------+---------------+----------+
| real       |        0.1503 |  -2.6585 |
| user       |        0.0431 |  -2.2984 |
| sys        |        0.1870 |  -3.2013 |
+------------+---------------+----------+

Here, variation is the coefficient of variation, i.e.  standard deviation
/ mean.

[joshua.hahnjy@gmail.com: simplify checks]
  Link: https://lkml.kernel.org/r/20251014192827.851389-1-joshua.hahnjy@gmail.com
Link: https://lkml.kernel.org/r/20251014145011.3427205-4-joshua.hahnjy@gmail.com
Signed-off-by: Joshua Hahn <joshua.hahnjy@gmail.com>
Suggested-by: Chris Mason <clm@fb.com>
Co-developed-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Brendan Jackman <jackmanb@google.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Michal Hocko <mhocko@suse.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-16 17:28:05 -08:00
Joshua Hahn
fc4b909c36 mm/page_alloc: batch page freeing in decay_pcp_high
It is possible for pcp->count - pcp->high to exceed pcp->batch by a lot. 
When this happens, we should perform batching to ensure that
free_pcppages_bulk isn't called with too many pages to free at once and
starve out other threads that need the pcp or zone lock.

Since we are still only freeing the difference between the initial
pcp->count and pcp->high values, there should be no change to how many
pages are freed.

Link: https://lkml.kernel.org/r/20251014145011.3427205-3-joshua.hahnjy@gmail.com
Signed-off-by: Joshua Hahn <joshua.hahnjy@gmail.com>
Suggested-by: Chris Mason <clm@fb.com>
Suggested-by: Andrew Morton <akpm@linux-foundation.org>
Co-developed-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Brendan Jackman <jackmanb@google.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Michal Hocko <mhocko@suse.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-16 17:28:04 -08:00
Joshua Hahn
0acc67c403 mm/page_alloc/vmstat: simplify refresh_cpu_vm_stats change detection
Patch series "mm/page_alloc: Batch callers of free_pcppages_bulk", v5.

Motivation & Approach
=====================

While testing workloads with high sustained memory pressure on large
machines in the Meta fleet (1Tb memory, 316 CPUs), we saw an unexpectedly
high number of softlockups.  Further investigation showed that the zone
lock in free_pcppages_bulk was being held for a long time, and was called
to free 2k+ pages over 100 times just during boot.

This causes starvation in other processes for the zone lock, which can
lead to the system stalling as multiple threads cannot make progress
without the locks.  We can see these issues manifesting as warnings:

[ 4512.591979] rcu: INFO: rcu_sched self-detected stall on CPU
[ 4512.604370] rcu:     20-....: (9312 ticks this GP) idle=a654/1/0x4000000000000000 softirq=309340/309344 fqs=5426
[ 4512.626401] rcu:              hardirqs   softirqs   csw/system
[ 4512.638793] rcu:      number:        0        145            0
[ 4512.651177] rcu:     cputime:       30      10410          174   ==> 10558(ms)
[ 4512.666657] rcu:     (t=21077 jiffies g=783665 q=1242213 ncpus=316)

While these warnings don't indicate a crash or a kernel panic, they do
point to the underlying issue of lock contention.  To prevent starvation
in both locks, batch the freeing of pages using pcp->batch.

Because free_pcppages_bulk is called with the pcp lock and acquires the
zone lock, relinquishing and reacquiring the locks are only effective when
both of them are broken together (unless the system was built with queued
spinlocks).  Thus, instead of modifying free_pcppages_bulk to break both
locks, batch the freeing from its callers instead.

A similar fix has been implemented in the Meta fleet, and we have seen
significantly less softlockups.

Testing
=======
The following are a few synthetic benchmarks, made on three machines. The
first is a large machine with 754GiB memory and 316 processors.
The second is a relatively smaller machine with 251GiB memory and 176
processors. The third and final is the smallest of the three, which has 62GiB
memory and 36 processors.

On all machines, I kick off a kernel build with -j$(nproc).
Negative delta is better (faster compilation).

Large machine (754GiB memory, 316 processors)
make -j$(nproc)
+------------+---------------+-----------+
| Metric (s) | Variation (%) | Delta(%)  |
+------------+---------------+-----------+
| real       |        0.8070 |  - 1.4865 |
| user       |        0.2823 |  + 0.4081 |
| sys        |        5.0267 |  -11.8737 |
+------------+---------------+-----------+

Medium machine (251GiB memory, 176 processors)
make -j$(nproc)
+------------+---------------+----------+
| Metric (s) | Variation (%) | Delta(%) |
+------------+---------------+----------+
| real       |        0.2806 |  +0.0351 |
| user       |        0.0994 |  +0.3170 |
| sys        |        0.6229 |  -0.6277 |
+------------+---------------+----------+

Small machine (62GiB memory, 36 processors)
make -j$(nproc)
+------------+---------------+----------+
| Metric (s) | Variation (%) | Delta(%) |
+------------+---------------+----------+
| real       |        0.1503 |  -2.6585 |
| user       |        0.0431 |  -2.2984 |
| sys        |        0.1870 |  -3.2013 |
+------------+---------------+----------+

Here, variation is the coefficient of variation, i.e.  standard deviation
/ mean.

Based on these results, it seems like there are varying degrees to how
much lock contention this reduces.  For the largest and smallest machines
that I ran the tests on, it seems like there is quite some significant
reduction.  There is also some performance increases visible from
userspace.

Interestingly, the performance gains don't scale with the size of the
machine, but rather there seems to be a dip in the gain there is for the
medium-sized machine.  One possible theory is that because the high
watermark depends on both memory and the number of local CPUs, what
impacts zone contention the most is not these individual values, but
rather the ratio of mem:processors.


This patch (of 5):

Currently, refresh_cpu_vm_stats returns an int, indicating how many
changes were made during its updates.  Using this information, callers
like vmstat_update can heuristically determine if more work will be done
in the future.

However, all of refresh_cpu_vm_stats's callers either (a) ignore the
result, only caring about performing the updates, or (b) only care about
whether changes were made, but not *how many* changes were made.

Simplify the code by returning a bool instead to indicate if updates
were made.

In addition, simplify fold_diff and decay_pcp_high to return a bool
for the same reason.

Link: https://lkml.kernel.org/r/20251014145011.3427205-1-joshua.hahnjy@gmail.com
Link: https://lkml.kernel.org/r/20251014145011.3427205-2-joshua.hahnjy@gmail.com
Signed-off-by: Joshua Hahn <joshua.hahnjy@gmail.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: SeongJae Park <sj@kernel.org>
Cc: Brendan Jackman <jackmanb@google.com>
Cc: Chris Mason <clm@fb.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-16 17:28:04 -08:00
Kefeng Wang
f66e2727dd mm: huge_memory: use folio_can_map_prot_numa() for pmd folio
The folio_can_map_prot_numa() checks whether the folio can map prot numa,
which skips unsuitable folio, i.e.  zone device, shared folios (KSM, CoW),
non-movable dma pinned, dirty file folio and folios that already have the
expected node affinity.  Although the ksm only applies to small folios, an
extra test was added for large folios, but the other policies should be
applied to pmd folio, which helps to avoid unnecessary pmd change and
folio migration attempts.

Link: https://lkml.kernel.org/r/20251023113737.3572790-5-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-16 17:28:04 -08:00
Kefeng Wang
ca43034cdb mm: mprotect: convert to folio_can_map_prot_numa()
The prot_numa_skip() naming is not good since it updates the folio access
time except checking whether to skip prot NUMA, so rename it to
folio_can_map_prot_numa(), and cleanup it a bit, remove ret by directly
return value instead of goto style.

Adding a new helper vma_is_single_threaded_private() to check whether it's
a single threaded private VMA, and make folio_can_map_prot_numa() a
non-static function so that they could be reused in change_huge_pmd(),
since folio_can_map_prot_numa() will be shared in different paths, let's
move it near change_prot_numa() in mempolicy.c.

Link: https://lkml.kernel.org/r/20251023113737.3572790-4-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-16 17:28:03 -08:00
Kefeng Wang
6e97624dac mm: mprotect: avoid unnecessary struct page accessing if pte_protnone()
If the pte_protnone() is true, we could avoid unnecessary struct page
accessing and reduce cache footprint when scanning page tables for prot
numa, there was a similar change before, see more commit a818f5363a
("autonuma: reduce cache footprint when scanning page tables").

Link: https://lkml.kernel.org/r/20251023113737.3572790-3-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Acked-by: Zi Yan <ziy@nvidia.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Dev Jain <dev.jain@arm.com>
Reviewed-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-16 17:28:03 -08:00