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2025-11-16mm/khugepaged: factor out common logic in [scan,alloc]_sleep_millisecs_store()Leon Hwang
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>
2025-11-16mm/damon/sysfs: remove misleading todo comment in nid_show()Swaraj Gaikwad
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>
2025-11-16mm/vmalloc: use kmalloc_array() instead of kmalloc()Mehdi Ben Hadj Khelifa
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>
2025-11-16vmalloc: separate gfp_mask adjunctive parentheses in __vmalloc_node_noprof() ↵Bagas Sanjaya
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>
2025-11-16mm: add shmem_zero_setup_desc()Lorenzo Stoakes
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>
2025-11-16mm/hugetlbfs: update hugetlbfs to use mmap_prepareLorenzo Stoakes
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>
2025-11-16mm: add ability to take further action in vm_area_descLorenzo Stoakes
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>
2025-11-16mm: introduce io_remap_pfn_range_[prepare, complete]()Lorenzo Stoakes
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>
2025-11-16mm: add remap_pfn_range_prepare(), remap_pfn_range_complete()Lorenzo Stoakes
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 9a4f90e24661 ("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>
2025-11-16mm/vma: rename __mmap_prepare() function to avoid confusionLorenzo Stoakes
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>
2025-11-16mm: add vma_desc_size(), vma_desc_pages() helpersLorenzo Stoakes
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>
2025-11-16mm/vma: remove unused function, make internal functions staticLorenzo Stoakes
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>
2025-11-16mm/shmem: update shmem to use mmap_prepareLorenzo Stoakes
Patch series "expand mmap_prepare functionality, port more users", v5. Since commit c84bf6dd2b83 ("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>
2025-11-16mm/damon/reclaim: use min_sz_region for core address alignment when setting ↵Quanmin Yan
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: 7db551fcfb2a ("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>
2025-11-16mm/damon: add a min_sz_region parameter to ↵Quanmin Yan
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: 2e0fe9245d6b ("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>
2025-11-16mm/khugepaged: guard is_zero_pfn() calls with pte_present()Lance Yang
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>
2025-11-16mm/damon/sysfs-schemes: support DAMOS_QUOTA_NODE_MEMCG_FREE_BPSeongJae Park
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>
2025-11-16mm/damon/core: add DAMOS quota gaol metric for per-memcg per-numa free memorySeongJae Park
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>
2025-11-16mm/damon/sysfs-schemes: support DAMOS_QUOTA_NODE_MEMCG_USED_BPSeongJae Park
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>
2025-11-16mm/damon/sysfs-schemes: implement path file under quota goal directorySeongJae Park
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>
2025-11-16mm/damon/core: implement DAMOS_QUOTA_NODE_MEMCG_USED_BPSeongJae Park
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>
2025-11-16mm: vmscan: simplify the logic for activating dirty file foliosBaolin Wang
After commit 6b0dfabb3555 ("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>
2025-11-16mm: vmscan: filter out the dirty file folios for node_reclaim()Baolin Wang
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 6b0dfabb3555 ("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>
2025-11-16memcg: net: track network throttling due to memcg memory pressureShakeel Butt
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>
2025-11-16mm/khugepaged: fix comment for default scan sleep durationwang lian
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>
2025-11-16mm/page_alloc: simplify and cleanup pcp lockingVlastimil Babka
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>
2025-11-16mm/page_alloc: batch page freeing in free_frozen_page_commitJoshua Hahn
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>
2025-11-16mm/page_alloc: batch page freeing in decay_pcp_highJoshua Hahn
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>
2025-11-16mm/page_alloc/vmstat: simplify refresh_cpu_vm_stats change detectionJoshua Hahn
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>
2025-11-16mm: huge_memory: use folio_can_map_prot_numa() for pmd folioKefeng Wang
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>
2025-11-16mm: mprotect: convert to folio_can_map_prot_numa()Kefeng Wang
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>
2025-11-16mm: mprotect: avoid unnecessary struct page accessing if pte_protnone()Kefeng Wang
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 a818f5363a0e ("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>
2025-11-16mm: mprotect: always skip dma pinned folio in prot_numa_skip()Kefeng Wang
Patch series "mm: some optimizations for prot numa", v5. This patch (of 4): If the folio (even not CoW folio) is dma pinned, it can't be migrated due to the elevated reference count. So always skip a pinned folio to avoid wasting cycles when folios are migrated. Link: https://lkml.kernel.org/r/20251023113737.3572790-1-wangkefeng.wang@huawei.com Link: https://lkml.kernel.org/r/20251023113737.3572790-2-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: Barry Song <baohua@kernel.org> Reviewed-by: Dev Jain <dev.jain@arm.com> Reviewed-by: Lance Yang <lance.yang@linux.dev> 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: Liam Howlett <liam.howlett@oracle.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-16drivers/base/node: fold unregister_node() into unregister_one_node()Donet Tom
unregister_node() is only called from unregister_one_node(). This patch folds unregister_node() into its only caller and renames unregister_one_node() to unregister_node(). This reduces unnecessary indirection and simplifies the code structure. No functional changes are introduced. [donettom@linux.ibm.com: remove extra spaces before @nid and "All"] Link: https://lkml.kernel.org/r/cff01514-9074-4c97-bcf1-d4e3594e48b0@linux.ibm.com Link: https://lkml.kernel.org/r/32b7d5d8f0f30d313c3e1d8798f591459c8746f9.1760097208.git.donettom@linux.ibm.com Signed-off-by: Donet Tom <donettom@linux.ibm.com> Acked-by: David Hildenbrand <david@redhat.com> Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Acked-by: SeongJae Park <sj@kernel.org> Cc: Aboorva Devarajan <aboorvad@linux.ibm.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Danilo Krummrich <dakr@kernel.org> Cc: Dave Jiang <dave.jiang@intel.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Madhavan Srinivasan <maddy@linux.ibm.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-16drivers/base/node: fold register_node() into register_one_node()Donet Tom
Patch series "drivers/base/node: fold node register and unregister functions", v2. The first patch merges register_one_node() and register_node(), leaving a single register_node() function. The second patch merges unregister_one_node() and unregister_node(), leaving a single unregister_node() function. There are no functional changes in these patches. This patch (of 2): register_node() is only called from register_one_node(). This patch folds register_node() into its only caller and renames register_one_node() to register_node(). This reduces unnecessary indirection and simplifies the code structure. No functional changes are introduced. [akpm@linux-foundation.org: fix kerneldoc, per David] Link: https://lkml.kernel.org/r/cover.1760097207.git.donettom@linux.ibm.com Link: https://lkml.kernel.org/r/910853c9dd61f7a2190a56cba101e73e9c6859be.1760097207.git.donettom@linux.ibm.com Signed-off-by: Donet Tom <donettom@linux.ibm.com> Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Acked-by: SeongJae Park <sj@kernel.org> Acked-by: David Hildenbrand <david@redhat.com> Cc: Aboorva Devarajan <aboorvad@linux.ibm.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Danilo Krummrich <dakr@kernel.org> Cc: Dave Jiang <dave.jiang@intel.com> Cc: David Hildenbrand <david@redhat.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Madhavan Srinivasan <maddy@linux.ibm.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-16mm: remove the BOUNCE config optionHuacai Chen
Commit eeadd68e2a5f ("block: remove bounce buffering support") remove block/bounce.c but left the BOUNCE config option. Now this option has no users, so remove it. Link: https://lkml.kernel.org/r/20251013095620.1111061-1-chenhuacai@loongson.cn Signed-off-by: Huacai Chen <chenhuacai@loongson.cn> Acked-by: David Hildenbrand <david@redhat.com> Acked-by: Jens Axboe <axboe@kernel.dk> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Hannes Reinecke <hare@suse.de> Cc: Johannes Thumshirn <johannes.thumshirn@wdc.com> Cc: John Garry <john.g.garry@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-16vmalloc: update __vmalloc_node_noprof() documentationUladzislau Rezki (Sony)
The kernel-doc for __vmalloc_node_noprof() incorrectly states that __GFP_NOFAIL reclaim modifier is not supported. In fact it has been supported since commit 9376130c390a ("mm/vmalloc: add support for __GFP_NOFAIL"). To avoid duplication and future drift, point this helper's doc to __vmalloc_node_range_noprof() for details and the full description. Link: https://lkml.kernel.org/r/20251013174222.90123-1-urezki@gmail.com Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com> Reviewed-by: Baoquan He <bhe@redhat.com> Cc: Michal Hocko <mhocko@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-16mm: vmalloc: WARN_ON if mapping size is not PAGE_SIZE alignedYadong Qi
In mm/vmalloc.c, the function vmap_pte_range() assumes that the mapping size is aligned to PAGE_SIZE. If this assumption is violated, the loop will become infinite because the termination condition (`addr != end`) will never be met. This can lead to overwriting other VA ranges and/or random pages physically follow the page table. It's the caller's responsibility to ensure that the mapping size is aligned to PAGE_SIZE. However, the memory corruption is hard to root cause. To identify the programming error in the caller easier, check whether the mapping size is PAGE_SIZE aligned with WARN_ON_ONCE(). [yadong.qi@linux.alibaba.com: fix uninitialized value issue] Closes: https://lore.kernel.org/r/202510110050.VG9YKMRK-lkp@intel.com/ Link: https://lkml.kernel.org/r/20251010014311.1689-1-yadong.qi@linux.alibaba.com Signed-off-by: Yadong Qi <yadong.qi@linux.alibaba.com> Reviewed-by: Huang Ying <ying.huang@linux.alibaba.com> Reviewed-by: Dev Jain <dev.jain@arm.com> Reviewed-by: Uladzislau Rezki (Sony) <urezki@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-16mm/page_owner: simplify zone iteration logic in init_early_allocated_pages()Song Hu
The current implementation uses nested loops: first iterating over all online nodes, then over zones within each node. This can be simplified by using the for_each_populated_zone() macro which directly iterates through all populated zones. This change: 1. Removes the intermediate init_zones_in_node() function 2. Simplifies init_early_allocated_pages() to use direct zone iteration 3. Updates init_pages_in_zone() to take only zone parameter and access node_id via zone->zone_pgdat The functionality remains identical, but the code is cleaner and more maintainable. Link: https://lkml.kernel.org/r/20250930092153.843109-2-husong@kylinos.cn Signed-off-by: Song Hu <husong@kylinos.cn> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Ye Liu <liuye@kylinos.cn> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Brendan Jackman <jackmanb@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> 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>
2025-11-16mm/page_owner: rename proc-prefixed variables for claritySong Hu
`proc_page_owner_operations` and related variables were renamed to `page_owner_fops` to better reflect their association with `debugfs` rather than `/proc`. This improves code clarity and aligns with kernel naming conventions. Link: https://lkml.kernel.org/r/20250930092153.843109-1-husong@kylinos.cn Signed-off-by: Song Hu <husong@kylinos.cn> Acked-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Ye Liu <liuye@kylinos.cn> Cc: Brendan Jackman <jackmanb@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> 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>
2025-11-16kasan: cleanup of kasan_enabled() checksSabyrzhan Tasbolatov
Deduplication of kasan_enabled() checks which are already used by callers. * Altered functions: check_page_allocation Delete the check because callers have it already in __wrappers in include/linux/kasan.h: __kasan_kfree_large __kasan_mempool_poison_pages __kasan_mempool_poison_object kasan_populate_vmalloc, kasan_release_vmalloc Add __wrappers in include/linux/kasan.h. They are called externally in mm/vmalloc.c. __kasan_unpoison_vmalloc, __kasan_poison_vmalloc Delete checks because there're already kasan_enabled() checks in respective __wrappers in include/linux/kasan.h. release_free_meta -- Delete the check because the higher caller path has it already. See the stack trace: __kasan_slab_free -- has the check already __kasan_mempool_poison_object -- has the check already poison_slab_object kasan_save_free_info release_free_meta kasan_enabled() -- Delete here Link: https://lkml.kernel.org/r/20251009155403.1379150-3-snovitoll@gmail.com Signed-off-by: Sabyrzhan Tasbolatov <snovitoll@gmail.com> Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com> Cc: Alexander Potapenko <glider@google.com> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Cc: Baoquan He <bhe@redhat.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Dmitriy Vyukov <dvyukov@google.com> Cc: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com> Cc: Vincenzo Frascino <vincenzo.frascino@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-16kasan: remove __kasan_save_free_info wrapperSabyrzhan Tasbolatov
Patch series "kasan: cleanups for kasan_enabled() checks". This patch series is the continuation of [1] the previous discussion related to the KASAN internal refactoring. Here we remove kasan_enabled() checks which are duplicated by higher callers. These checks deduplication are also related to the separate patch series [2]. This patch (of 2): We don't need a kasan_enabled() check in kasan_save_free_info() at all. Both the higher level paths (kasan_slab_free and kasan_mempool_poison_object) already contain this check. Therefore, remove the __wrapper. Link: https://lkml.kernel.org/r/20251009155403.1379150-1-snovitoll@gmail.com Link: https://lkml.kernel.org/r/20251009155403.1379150-2-snovitoll@gmail.com Link: https://lore.kernel.org/all/CA+fCnZce3AR+pUesbDkKMtMJ+iR8eDrcjFTbVpAcwjBoZ=gJnQ@mail.gmail.com/ [1] Link: https://lore.kernel.org/all/aNTfPjS2buXMI46D@MiWiFi-R3L-srv/ [2] Signed-off-by: Sabyrzhan Tasbolatov <snovitoll@gmail.com> Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com> Cc: Alexander Potapenko <glider@google.com> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Cc: Baoquan He <bhe@redhat.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Dmitriy Vyukov <dvyukov@google.com> Cc: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com> Cc: Vincenzo Frascino <vincenzo.frascino@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-16mm/userfaultfd: don't lock anon_vma when performing UFFDIO_MOVELokesh Gidra
Now that rmap_walk() is guaranteed to be called with the folio lock held, we can stop serializing on the src VMA anon_vma lock when moving an exclusive folio from a src VMA to a dst VMA in UFFDIO_MOVE ioctl. When moving a folio, we modify folio->mapping through folio_move_anon_rmap() and adjust folio->index accordingly. Doing that while we could have concurrent RMAP walks would be dangerous. Therefore, to avoid that, we had to acquire anon_vma of src VMA in write-mode. That meant that when multiple threads called UFFDIO_MOVE concurrently on distinct pages of the same src VMA, they would serialize on it, hurting scalability. In addition to avoiding the scalability bottleneck, this patch also simplifies the complicated lock dance that UFFDIO_MOVE has to go through between RCU, folio-lock, ptl, and anon_vma. folio_move_anon_rmap() already enforces that the folio is locked. So when we have the folio locked we can no longer race with concurrent rmap_walk() as used by folio_referenced() and others who call it on unlocked non-KSM anon folios, and therefore the anon_vma lock is no longer required. Note that this handling is now the same as for other folio_move_anon_rmap() users that also do not hold the anon_vma lock -- namely COW reuse handling (do_wp_page()->wp_can_reuse_anon_folio(), do_huge_pmd_wp_page(), and hugetlb_wp()). These users never required the anon_vma lock as they are only moving the anon VMA closer to the anon_vma leaf of the VMA, for example, from an anon_vma root to a leaf of that root. rmap walks were always able to tolerate that scenario. Link: https://lkml.kernel.org/r/20250923071019.775806-3-lokeshgidra@google.com Signed-off-by: Lokesh Gidra <lokeshgidra@google.com> Acked-by: David Hildenbrand <david@redhat.com> Acked-by: Peter Xu <peterx@redhat.com> Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Barry Song <baohua@kernel.org> Cc: Jann Horn <jannh@google.com> Cc: Kalesh Singh <kaleshsingh@google.com> Cc: Lokesh Gidra <lokeshgidra@google.com> Cc: Nicolas Geoffray <ngeoffray@google.com> Cc: Harry Yoo <harry.yoo@oracle.com> Cc: SeongJae Park <sj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-16mm: always call rmap_walk() on locked foliosLokesh Gidra
Patch series "Improve UFFDIO_MOVE scalability by removing anon_vma lock", v2. Userfaultfd has a scalability issue in its UFFDIO_MOVE ioctl, which is heavily used in Android as its java garbage collector uses it for concurrent heap compaction. The issue arises because UFFDIO_MOVE updates folio->mapping to an anon_vma with a different root, in order to move the folio from a src VMA to dst VMA. It performs the operation with the folio locked, but this is insufficient, because rmap_walk() can be performed on non-KSM anonymous folios without folio lock. This means that UFFDIO_MOVE has to acquire the anon_vma write lock of the root anon_vma belonging to the folio it wishes to move. This causes scalability bottleneck when multiple threads perform UFFDIO_MOVE simultanously on distinct pages of the same src VMA. In field traces of arm64 android devices, we have observed janky user interactions due to long (sometimes over ~50ms) uninterruptible sleeps on main UI thread caused by anon_vma lock contention in UFFDIO_MOVE. This is particularly severe during the beginning of GC's compaction phase when it is likely to have multiple threads involved. This patch resolves the issue by removing the exception in rmap_walk() for non-KSM anon folios by ensuring that all folios are locked during rmap walk. This is less problematic than it might seem, as the only major caller which utilises this mode is shrink_active_list(), which is covered in detail in the first patch of this series. As a result of changing our approach to locking, we can remove all the code that took steps to acquire an anon_vma write lock instead of a folio lock. This results in a significant simplification and scalability improvement of the code (currently only in UFFDIO_MOVE). Furthermore, as a side-effect, folio_lock_anon_vma_read() gets simpler as we don't need to worry that folio->mapping may have changed under us. This patch (of 2): Guarantee that rmap_walk() is called on locked folios so that threads changing folio->mapping and folio->index for non-KSM anon folios can serialize on fine-grained folio lock rather than anon_vma lock. Other folio types are already always locked before rmap_walk(). With this, we are going from 'not necessarily' locking the non-KSM anon folio to 'definitely' locking it during rmap walks. This patch is in preparation for removing anon_vma write-lock from UFFDIO_MOVE. With this patch, three functions are now expected to be called with a locked folio. To be careful of not missing any case, here is the exhaustive list of all their callers. 1) rmap_walk() is called from: a) folio_referenced() b) damon_folio_mkold() c) damon_folio_young() d) page_idle_clear_pte_refs() e) try_to_unmap() f) try_to_migrate() g) folio_mkclean() h) remove_migration_ptes() In the above list, first 4 are changed in this patch to try-lock non-KSM anon folios, similar to other types of folios. The remaining functions in the list already hold folio lock when calling rmap_walk(). 2) folio_lock_anon_vma_read() is called from following functions: a) collect_procs_anon() b) page_idle_clear_pte_refs() c) damon_folio_mkold() d) damon_folio_young() e) folio_referenced() f) try_to_unmap() g) try_to_migrate() All the functions in above list, except collect_procs_anon(), are covered by the rmap_walk() list above. For collect_procs_anon(), with kill_procs_now() changed to take folio lock in this patch ensures that all callers of folio_lock_anon_vma_read() now hold the lock. 3) folio_get_anon_vma() is called from following functions, all of which already hold the folio lock: a) move_pages_huge_pmd() b) __folio_split() c) move_pages_ptes() d) migrate_folio_unmap() e) unmap_and_move_huge_page() Functionally, this patch doesn't break the logic because rmap walkers generally do some other check to see if what is expected to mapped did happen so it's fine, or otherwise treat things as best-effort. Among the 4 functions changed in this patch, folio_referenced() is the only core-mm function, and is also frequently accessed. To assess the impact of locking non-KSM anon folios in shrink_active_list()->folio_referenced() path, we performed an app cycle test on an arm64 android device. During the whole duration of the test there were over 140k invocations of shrink_active_list(), out of which over 29k had at least one non-KSM anon folio on which folio_referenced() was called. In none of these invocations folio_trylock() failed. Of course, we now take a lock where we wouldn't previously have. In the past it would have had a major impact in causing a CoW write fault to copy a page in do_wp_page(), as commit 09854ba94c6a ("mm: do_wp_page() simplification") caused a failure to obtain folio lock to result in a page copy even if one wasn't necessary. However, since commit 6c287605fd56 ("mm: remember exclusively mapped anonymous pages with PG_anon_exclusive"), and the introduction of the folio anon exclusive flag, this issue is significantly mitigated. The only case remaining that we might worry about from this perspective is that of read-only folios immediately after fork where the anon exclusive bit will not have been set yet. We note however in the case of read-only just-forked folios that wp_can_reuse_anon_folio() will notice the raised reference count established by shrink_active_list() via isolate_lru_folios() and refuse to reuse in any case, so this will in fact have no impact - the folio lock is ultimately immaterial here. All-in-all it appears that there is little opportunity for meaningful negative impact from this change. Link: https://lkml.kernel.org/r/20250923071019.775806-1-lokeshgidra@google.com Link: https://lkml.kernel.org/r/20250923071019.775806-2-lokeshgidra@google.com Signed-off-by: Lokesh Gidra <lokeshgidra@google.com> Acked-by: David Hildenbrand <david@redhat.com> Acked-by: Peter Xu <peterx@redhat.com> Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Harry Yoo <harry.yoo@oracle.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Barry Song <baohua@kernel.org> Cc: SeongJae Park <sj@kernel.org> Cc: Jann Horn <jannh@google.com> Cc: Kalesh Singh <kaleshsingh@google.com> Cc: Nicolas Geoffray <ngeoffray@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-16mm/hugetlb: allow overcommitting gigantic hugepagesUsama Arif
Currently, gigantic hugepages cannot use the overcommit mechanism (nr_overcommit_hugepages), forcing users to permanently reserve memory via nr_hugepages even when pages might not be actively used. The restriction was added in 2011 [1], which was before there was support for reserving 1G hugepages at runtime. Remove this blanket restriction on gigantic hugepage overcommit. This will bring the same benefits to gigantic pages as hugepages: - Memory is only taken out of regular use when actually needed - Unused surplus pages can be returned to the system - Better memory utilization, especially with CMA backing which can significantly increase the changes of hugepage allocation Without this patch: echo 3 > /sys/kernel/mm/hugepages/hugepages-1048576kB/nr_overcommit_hugepages bash: echo: write error: Invalid argument With this patch: echo 3 > /sys/kernel/mm/hugepages/hugepages-1048576kB/nr_overcommit_hugepages ./mmap_hugetlb_test Successfully allocated huge pages at address: 0x7f9d40000000 cat mmap_hugetlb_test.c ... unsigned long ALLOC_SIZE = 3 * (unsigned long) HUGE_PAGE_SIZE; addr = mmap(NULL, ALLOC_SIZE, // 3GB PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS | MAP_HUGETLB | MAP_HUGE_1GB, -1, 0); if (addr == MAP_FAILED) { fprintf(stderr, "mmap failed: %s\n", strerror(errno)); return 1; } printf("Successfully allocated huge pages at address: %p\n", addr); ... Link: https://lkml.kernel.org/r/20251009172433.4158118-2-usamaarif642@gmail.com Link: https://git.zx2c4.com/linux-rng/commit/mm/hugetlb.c?id=adbe8726dc2a3805630d517270db17e3af86e526 [1] Signed-off-by: Usama Arif <usamaarif642@gmail.com> Reviewed-by: Shakeel Butt <shakeel.butt@linux.dev> Reviewed-by: Kefeng Wang <wangkefeng.wang@huawei.com> Acked-by: Oscar Salvador <osalvador@suse.de> Cc: David Hildenbrand <david@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Muchun Song <muchun.song@linux.dev> Cc: Rik van Riel <riel@surriel.com> Cc: SeongJae Park <sj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-16mm/hugetlb: create hstate_is_gigantic_no_runtime helperUsama Arif
This is a common condition used to skip operations that cannot be performed on gigantic pages when runtime support is disabled. This helper is introduced as the condition will exist even more when allowing "overcommit" of gigantic hugepages. No functional change intended with this patch. Link: https://lkml.kernel.org/r/20251009172433.4158118-1-usamaarif642@gmail.com Signed-off-by: Usama Arif <usamaarif642@gmail.com> Suggested-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Shakeel Butt <shakeel.butt@linux.dev> Reviewed-by: Kefeng Wang <wangkefeng.wang@huawei.com> Acked-by: David Hildenbrand <david@redhat.com> Acked-by: Oscar Salvador <osalvador@suse.de> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Muchun Song <muchun.song@linux.dev> Cc: Rik van Riel <riel@surriel.com> Cc: SeongJae Park <sj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-16mm/page_alloc: prevent reporting pcp->batch = 0Joshua Hahn
zone_batchsize returns the appropriate value that should be used for pcp->batch. If it finds a zone with less than 4096 pages or PAGE_SIZE > 1M, however, it leads to some incorrect math. In the above case, we will get an intermediary value of 1, which is then rounded down to the nearest power of two, and 1 is subtracted from it. Since 1 is already a power of two, we will get batch = 1-1 = 0: batch = rounddown_pow_of_two(batch + batch/2) - 1; A pcp->batch value of 0 is nonsensical. If this were actually set, then functions like drain_zone_pages would become no-ops, since they could only free 0 pages at a time. Of the two callers of zone_batchsize, the one that is actually used to set pcp->batch works around this by setting pcp->batch to the maximum of 1 and zone_batchsize. However, the other caller, zone_pcp_init, incorrectly prints out the batch size of the zone to be 0. This is probably rare in a typical zone, but the DMA zone can often have less than 4096 pages, which means it will print out "LIFO batch:0". Before: [ 0.001216] DMA zone: 3998 pages, LIFO batch:0 After: [ 0.001210] DMA zone: 3998 pages, LIFO batch:1 Instead of dealing with the error handling and the mismatch between the reported and actual zone batchsize, just return 1 if the zone_batchsize is 1 page or less before the rounding. Link: https://lkml.kernel.org/r/20251009192933.3756712-3-joshua.hahnjy@gmail.com Signed-off-by: Joshua Hahn <joshua.hahnjy@gmail.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Brendan Jackman <jackmanb@google.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Johannes Weiner <hannes@cmpxchg.org> 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>
2025-11-16mm/page_alloc: clarify batch tuning in zone_batchsizeJoshua Hahn
Patch series "mm/page_alloc: pcp->batch cleanups", v2. Two small cleanups for mm/page_alloc. Patch 1 cleans up a misleading comment about how pcp->batch is calculated, and folds in the calculation to increase clarity. No functional change intended. Patch 2 corrects zones from reporting that their pcp->batch is 0 when it is actually 1. Namely, corrects ZONE_DMA from reporting that its batch size is 0. This patch (of 2): Recently while working on another patch about batching free_pcppages_bulk [1], I was curious why pcp->batch was always 63 on my machine. This led me to zone_batchsize(), where I found this set of lines to determine what the batch size should be for the host: batch = min(zone_managed_pages(zone) >> 10, SZ_1M / PAGE_SIZE); batch /= 4; /* We effectively *= 4 below */ if (batch < 1) batch = 1; All of this is good, except the comment above which says "We effectively *= 4 below". Nowhere else in the function zone_batchsize(), is there a corresponding multipliation by 4. Looking into the history of this, it seems like Dave Hansen had also noticed this back in 2013 [1]. Turns out there *used* to be a corresponding *= 4, which was turned into a *= 6 later on to be used in pageset_setup_from_batch_size(), which no longer exists. Despite this mismatch not being corrected in the comments, it seems that getting rid of the /= 4 leads to a performance regression on machines with less than 250G memory and 176 processors. As such, let us preserve the functionality but clean up the comments. Fold the /= 4 into the calculation above: bitshift by 10+2=12, and instead of dividing 1MB, divide 256KB and adjust the comments accordingly. No functional change intended. Link: https://lkml.kernel.org/r/20251009192933.3756712-1-joshua.hahnjy@gmail.com Link: https://lkml.kernel.org/r/20251009192933.3756712-2-joshua.hahnjy@gmail.com Link: https://lore.kernel.org/all/20251002204636.4016712-1-joshua.hahnjy@gmail.com/ [1] Signed-off-by: Joshua Hahn <joshua.hahnjy@gmail.com> Suggested-by: Dave Hansen <dave.hansen@intel.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Brendan Jackman <jackmanb@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> 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>
2025-11-16mm/page_owner: add debugfs file 'show_stacks_handles'Mauricio Faria de Oliveira
Add the file 'show_stacks_handles' to show just stack traces and their handles, in order to resolve stack traces and handles (i.e., to identify the stack traces for handles in previous reads from 'show_handles'). All stacks/handles must show up, regardless of their number of pages, that might have become zero or no longer make 'count_threshold', but made it in previous reads from 'show_handles' -- and need to be resolved later. P.S.: now, print the extra newline independently of the number of pages. Link: https://lkml.kernel.org/r/20251001175611.575861-5-mfo@igalia.com Signed-off-by: Mauricio Faria de Oliveira <mfo@igalia.com> Cc: Brendan Jackman <jackmanb@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-16mm/page_owner: add debugfs file 'show_handles'Mauricio Faria de Oliveira
Add the flag STACK_PRINT_FLAG_HANDLE to print a stack's handle number from stackdepot, and add the file 'show_handles' to show just handles and their number of pages. This is similar to 'show_stacks', with handles instead of stack traces. Link: https://lkml.kernel.org/r/20251001175611.575861-4-mfo@igalia.com Signed-off-by: Mauricio Faria de Oliveira <mfo@igalia.com> Reviewed-by: Oscar Salvador <osalvador@suse.de> Cc: Brendan Jackman <jackmanb@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>