linux.git/drivers/gpu/drm/ttm/ttm_backup.c, branch master

drm/ttm/pool: back up at native page order

2026-07-17T16:09:27Z

ttm_pool_split_for_swap() unconditionally splits high-order pool pages into order-0 pages before backup, so every compound the shrinker touches is shattered even when the rest of the system would prefer it stay intact. Under sustained kswapd pressure this fragments memory enough to drive other parts of MM into recovery loops. Back up each compound at its native order instead. In ttm_pool_backup(), hand the full compound to the new ttm_backup_backup_folio(), which backs up subpages to a contiguous range of shmem indices and returns the base handle plus the number of subpages actually backed up (@nr_backed). On full success, free the compound once at its native order -- no split_page(), no per-4K refcount juggling. A per-folio backup can't be made fully atomic under memory pressure: ttm_backup_backup_folio() must allocate shmem folios before source subpages can be released, so under true OOM any subpage may fail while the rest of the compound is still live. Two mechanisms handle this without regressing reclaim behaviour: - alloc_gfp gets __GFP_NOMEMALLOC whenever order > 0 (cleared again for order-0), so a high-order backup fails fast with -ENOMEM instead of draining kernel reserves, leaving them for other allocations under the same pressure. - If ttm_backup_backup_folio() still returns a short @nr_backed with a valid handle for the successfully-backed prefix, split the source compound with ttm_pool_split_for_swap(), free the prefix as order-0 pages (already safely in shmem), and retry the remaining subpages at order 0, where __GFP_NOMEMALLOC is cleared and reserves may be used as a last resort. This preserves the original split-on-OOM fallback while keeping the common case fragmentation-free, and preserves the "partial backup is allowed" contract (shrunken is incremented per subpage backed up). The restore-side leftover-page split in ttm_pool_restore_commit() is left as-is: it's unreachable in practice and not worth complicating the restore state machine to avoid. Testing: the existing backup_fault_inject point only truncated tt->num_pages, which never exercised the reactive split path above since it never left a compound partially backed up. Wire fault injection into ttm_backup_backup_folio() itself: past the first subpage of a compound, synthesize a -ENOMEM in place of shmem_read_folio_gfp() when should_fail() trips, producing the same short @nr_pages_backed a real failure would and forcing ttm_pool_backup() through the split-and-retry path. The fault_attr stays private to ttm_pool.c; ttm_backup.c reaches it through ttm_backup_fault_inject_folio(), declared in ttm_pool_internal.h. While converting the writeback branch to operate on the whole folio, the unlock condition after shmem_writeout() also changed from `if (ret)` to `if (ret == AOP_WRITEPAGE_ACTIVATE)`, matching the actual contract: shmem_writeout()/swap_writeout() only leave the folio locked when returning AOP_WRITEPAGE_ACTIVATE; any other return (including a hard error from arch_prepare_to_swap()) means the folio was already unlocked internally. The old `if (ret)` check would have double- unlocked in that hard-error case. Cc: Christian Koenig Cc: Huang Rui Cc: Matthew Auld Cc: Maarten Lankhorst Cc: Maxime Ripard Cc: Thomas Zimmermann Cc: David Airlie Cc: Simona Vetter Cc: dri-devel@lists.freedesktop.org Cc: linux-kernel@vger.kernel.org Cc: stable@vger.kernel.org Fixes: b63d715b8090 ("drm/ttm/pool, drm/ttm/tt: Provide a helper to shrink pages") Suggested-by: Thomas Hellström Assisted-by: Claude:claude-opus-4.6 Signed-off-by: Matthew Brost Reviewed-by: Thomas Hellström Link: https://patch.msgid.link/20260716201358.4086085-1-matthew.brost@intel.com

drm/ttm: Avoid invoking the OOM killer when reading back swapped content

2026-03-20T09:38:10Z

In situations where the system is very short on RAM, the shmem readback from swap-space may invoke the OOM killer. However, since this might be a recoverable situation where the caller is indicating this by setting struct ttm_operation_ctx::gfp_retry_mayfail to true, adjust the gfp value used by the allocation accordingly. Signed-off-by: Thomas Hellström Reviewed-by: Maarten Lankhorst Acked-by: Christian König Link: https://patch.msgid.link/20260317141856.237876-3-thomas.hellstrom@linux.intel.com

mm: update shmem_[kernel]_file_*() functions to use vma_flags_t

2026-02-12T23:42:58Z

In order to be able to use only vma_flags_t in vm_area_desc we must adjust shmem file setup functions to operate in terms of vma_flags_t rather than vm_flags_t. This patch makes this change and updates all callers to use the new functions. No functional changes intended. [akpm@linux-foundation.org: comment fixes, per Baolin] Link: https://lkml.kernel.org/r/736febd280eb484d79cef5cf55b8a6f79ad832d2.1769097829.git.lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes Reviewed-by: Baolin Wang Reviewed-by: Jarkko Sakkinen Reviewed-by: Liam R. Howlett Cc: Barry Song Cc: David Hildenbrand Cc: Dev Jain Cc: Jason Gunthorpe Cc: Suren Baghdasaryan Cc: Vlastimil Babka Cc: Zi Yan Cc: "Darrick J. Wong" Cc: Damien Le Moal Cc: Yury Norov Cc: Chris Mason Cc: Pedro Falcato Signed-off-by: Andrew Morton

Merge tag 'mm-stable-2025-07-30-15-25' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2025-07-31T21:57:54Z

Pull MM updates from Andrew Morton: "As usual, many cleanups. The below blurbiage describes 42 patchsets. 21 of those are partially or fully cleanup work. "cleans up", "cleanup", "maintainability", "rationalizes", etc. I never knew the MM code was so dirty. "mm: ksm: prevent KSM from breaking merging of new VMAs" (Lorenzo Stoakes) addresses an issue with KSM's PR_SET_MEMORY_MERGE mode: newly mapped VMAs were not eligible for merging with existing adjacent VMAs. "mm/damon: introduce DAMON_STAT for simple and practical access monitoring" (SeongJae Park) adds a new kernel module which simplifies the setup and usage of DAMON in production environments. "stop passing a writeback_control to swap/shmem writeout" (Christoph Hellwig) is a cleanup to the writeback code which removes a couple of pointers from struct writeback_control. "drivers/base/node.c: optimization and cleanups" (Donet Tom) contains largely uncorrelated cleanups to the NUMA node setup and management code. "mm: userfaultfd: assorted fixes and cleanups" (Tal Zussman) does some maintenance work on the userfaultfd code. "Readahead tweaks for larger folios" (Ryan Roberts) implements some tuneups for pagecache readahead when it is reading into order>0 folios. "selftests/mm: Tweaks to the cow test" (Mark Brown) provides some cleanups and consistency improvements to the selftests code. "Optimize mremap() for large folios" (Dev Jain) does that. A 37% reduction in execution time was measured in a memset+mremap+munmap microbenchmark. "Remove zero_user()" (Matthew Wilcox) expunges zero_user() in favor of the more modern memzero_page(). "mm/huge_memory: vmf_insert_folio_*() and vmf_insert_pfn_pud() fixes" (David Hildenbrand) addresses some warts which David noticed in the huge page code. These were not known to be causing any issues at this time. "mm/damon: use alloc_migrate_target() for DAMOS_MIGRATE_{HOT,COLD" (SeongJae Park) provides some cleanup and consolidation work in DAMON. "use vm_flags_t consistently" (Lorenzo Stoakes) uses vm_flags_t in places where we were inappropriately using other types. "mm/memfd: Reserve hugetlb folios before allocation" (Vivek Kasireddy) increases the reliability of large page allocation in the memfd code. "mm: Remove pXX_devmap page table bit and pfn_t type" (Alistair Popple) removes several now-unneeded PFN_* flags. "mm/damon: decouple sysfs from core" (SeongJae Park) implememnts some cleanup and maintainability work in the DAMON sysfs layer. "madvise cleanup" (Lorenzo Stoakes) does quite a lot of cleanup/maintenance work in the madvise() code. "madvise anon_name cleanups" (Vlastimil Babka) provides additional cleanups on top or Lorenzo's effort. "Implement numa node notifier" (Oscar Salvador) creates a standalone notifier for NUMA node memory state changes. Previously these were lumped under the more general memory on/offline notifier. "Make MIGRATE_ISOLATE a standalone bit" (Zi Yan) cleans up the pageblock isolation code and fixes a potential issue which doesn't seem to cause any problems in practice. "selftests/damon: add python and drgn based DAMON sysfs functionality tests" (SeongJae Park) adds additional drgn- and python-based DAMON selftests which are more comprehensive than the existing selftest suite. "Misc rework on hugetlb faulting path" (Oscar Salvador) fixes a rather obscure deadlock in the hugetlb fault code and follows that fix with a series of cleanups. "cma: factor out allocation logic from __cma_declare_contiguous_nid" (Mike Rapoport) rationalizes and cleans up the highmem-specific code in the CMA allocator. "mm/migration: rework movable_ops page migration (part 1)" (David Hildenbrand) provides cleanups and future-preparedness to the migration code. "mm/damon: add trace events for auto-tuned monitoring intervals and DAMOS quota" (SeongJae Park) adds some tracepoints to some DAMON auto-tuning code. "mm/damon: fix misc bugs in DAMON modules" (SeongJae Park) does that. "mm/damon: misc cleanups" (SeongJae Park) also does what it claims. "mm: folio_pte_batch() improvements" (David Hildenbrand) cleans up the large folio PTE batching code. "mm/damon/vaddr: Allow interleaving in migrate_{hot,cold} actions" (SeongJae Park) facilitates dynamic alteration of DAMON's inter-node allocation policy. "Remove unmap_and_put_page()" (Vishal Moola) provides a couple of page->folio conversions. "mm: per-node proactive reclaim" (Davidlohr Bueso) implements a per-node control of proactive reclaim - beyond the current memcg-based implementation. "mm/damon: remove damon_callback" (SeongJae Park) replaces the damon_callback interface with a more general and powerful damon_call()+damos_walk() interface. "mm/mremap: permit mremap() move of multiple VMAs" (Lorenzo Stoakes) implements a number of mremap cleanups (of course) in preparation for adding new mremap() functionality: newly permit the remapping of multiple VMAs when the user is specifying MREMAP_FIXED. It still excludes some specialized situations where this cannot be performed reliably. "drop hugetlb_free_pgd_range()" (Anthony Yznaga) switches some sparc hugetlb code over to the generic version and removes the thus-unneeded hugetlb_free_pgd_range(). "mm/damon/sysfs: support periodic and automated stats update" (SeongJae Park) augments the present userspace-requested update of DAMON sysfs monitoring files. Automatic update is now provided, along with a tunable to control the update interval. "Some randome fixes and cleanups to swapfile" (Kemeng Shi) does what is claims. "mm: introduce snapshot_page" (Luiz Capitulino and David Hildenbrand) provides (and uses) a means by which debug-style functions can grab a copy of a pageframe and inspect it locklessly without tripping over the races inherent in operating on the live pageframe directly. "use per-vma locks for /proc/pid/maps reads" (Suren Baghdasaryan) addresses the large contention issues which can be triggered by reads from that procfs file. Latencies are reduced by more than half in some situations. The series also introduces several new selftests for the /proc/pid/maps interface. "__folio_split() clean up" (Zi Yan) cleans up __folio_split()! "Optimize mprotect() for large folios" (Dev Jain) provides some quite large (>3x) speedups to mprotect() when dealing with large folios. "selftests/mm: reuse FORCE_READ to replace "asm volatile("" : "+r" (XXX));" and some cleanup" (wang lian) does some cleanup work in the selftests code. "tools/testing: expand mremap testing" (Lorenzo Stoakes) extends the mremap() selftest in several ways, including adding more checking of Lorenzo's recently added "permit mremap() move of multiple VMAs" feature. "selftests/damon/sysfs.py: test all parameters" (SeongJae Park) extends the DAMON sysfs interface selftest so that it tests all possible user-requested parameters. Rather than the present minimal subset" * tag 'mm-stable-2025-07-30-15-25' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (370 commits) MAINTAINERS: add missing headers to mempory policy & migration section MAINTAINERS: add missing file to cgroup section MAINTAINERS: add MM MISC section, add missing files to MISC and CORE MAINTAINERS: add missing zsmalloc file MAINTAINERS: add missing files to page alloc section MAINTAINERS: add missing shrinker files MAINTAINERS: move memremap.[ch] to hotplug section MAINTAINERS: add missing mm_slot.h file THP section MAINTAINERS: add missing interval_tree.c to memory mapping section MAINTAINERS: add missing percpu-internal.h file to per-cpu section mm/page_alloc: remove trace_mm_alloc_contig_migrate_range_info() selftests/damon: introduce _common.sh to host shared function selftests/damon/sysfs.py: test runtime reduction of DAMON parameters selftests/damon/sysfs.py: test non-default parameters runtime commit selftests/damon/sysfs.py: generalize DAMON context commit assertion selftests/damon/sysfs.py: generalize monitoring attributes commit assertion selftests/damon/sysfs.py: generalize DAMOS schemes commit assertion selftests/damon/sysfs.py: test DAMOS filters commitment selftests/damon/sysfs.py: generalize DAMOS scheme commit assertion selftests/damon/sysfs.py: test DAMOS destinations commitment ...

mm: stop passing a writeback_control structure to shmem_writeout

2025-07-10T05:41:57Z

shmem_writeout only needs the swap_iocb cookie and the split folio list. Pass those explicitly and remove the now unused list member from struct writeback_control. Link: https://lkml.kernel.org/r/20250610054959.2057526-3-hch@lst.de Signed-off-by: Christoph Hellwig Cc: Baolin Wang Cc: Chengming Zhou Cc: Hugh Dickins Cc: Johannes Weiner Cc: Matthew Wilcox (Oracle) Cc: Nhat Pham Signed-off-by: Andrew Morton

drm/ttm: Include

2025-06-16T07:02:44Z

Fix the compile-time warnings drivers/gpu/drm/ttm/tests/ttm_kunit_helpers.c: warning: EXPORT_SYMBOL() is used, but #include is missing drivers/gpu/drm/ttm/tests/ttm_mock_manager.c: warning: EXPORT_SYMBOL() is used, but #include is missing drivers/gpu/drm/ttm/ttm_agp_backend.c: warning: EXPORT_SYMBOL() is used, but #include is missing drivers/gpu/drm/ttm/ttm_backup.c: warning: EXPORT_SYMBOL() is used, but #include is missing drivers/gpu/drm/ttm/ttm_bo.c: warning: EXPORT_SYMBOL() is used, but #include is missing drivers/gpu/drm/ttm/ttm_bo_util.c: warning: EXPORT_SYMBOL() is used, but #include is missing drivers/gpu/drm/ttm/ttm_bo_vm.c: warning: EXPORT_SYMBOL() is used, but #include is missing drivers/gpu/drm/ttm/ttm_device.c: warning: EXPORT_SYMBOL() is used, but #include is missing drivers/gpu/drm/ttm/ttm_execbuf_util.c: warning: EXPORT_SYMBOL() is used, but #include is missing drivers/gpu/drm/ttm/ttm_pool.c: warning: EXPORT_SYMBOL() is used, but #include is missing drivers/gpu/drm/ttm/ttm_range_manager.c: warning: EXPORT_SYMBOL() is used, but #include is missing drivers/gpu/drm/ttm/ttm_resource.c: warning: EXPORT_SYMBOL() is used, but #include is missing drivers/gpu/drm/ttm/ttm_tt.c: warning: EXPORT_SYMBOL() is used, but #include is missing Signed-off-by: Thomas Zimmermann Fixes: a934a57a42f6 ("scripts/misc-check: check missing #include when W=1") Reviewed-by: André Almeida Cc: Masahiro Yamada Cc: Nathan Chancellor Link: https://lore.kernel.org/r/20250612121633.229222-10-tzimmermann@suse.de

Merge tag 'vfs-6.16-rc1.writepage' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

2025-05-26T15:23:09Z

Pull final writepage conversion from Christian Brauner: "This converts vboxfs from ->writepage() to ->writepages(). This was the last user of the ->writepage() method. So remove ->writepage() completely and all references to it" * tag 'vfs-6.16-rc1.writepage' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: fs: Remove aops->writepage mm: Remove swap_writepage() and shmem_writepage() ttm: Call shmem_writeout() from ttm_backup_backup_page() i915: Use writeback_iter() shmem: Add shmem_writeout() writeback: Remove writeback_use_writepage() migrate: Remove call to ->writepage vboxsf: Convert to writepages 9p: Add a migrate_folio method

drm/ttm: Remove the struct ttm_backup abstraction

2025-05-06T08:57:27Z

The abstraction was previously added to support separate ttm_backup implementations. However with the current implementation casting from a struct file to a struct ttm_backup, we run into trouble since struct file may have randomized the layout and gcc complains. Remove the struct ttm_backup abstraction Cc: dri-devel@lists.freedesktop.org Cc: Matthew Brost Cc: Dave Airlie Cc: Christian König Cc: Matthew Auld Cc: Al Viro Reported-by: Kees Cook Closes: https://lore.kernel.org/dri-devel/9c8dbbafdaf9f3f089da2cde5a772d69579b3795.camel@linux.intel.com/T/#mb153ab9216cb813b92bdeb36f391ad4808c2ba29 Suggested-by: Christian König Fixes: 70d645deac98 ("drm/ttm: Add helpers for shrinking") Signed-off-by: Thomas Hellström Reviewed-by: Christian König Link: https://lore.kernel.org/r/20250502130014.3156-1-thomas.hellstrom@linux.intel.com

drm/ttm: Fix ttm_backup kerneldoc

2025-05-06T08:57:11Z

The docs were not properly updated from an earlier version of the code. Fixes: e7b5d23e5d47 ("drm/ttm: Provide a shmem backup implementation") Cc: Christian König Cc: Matthew Brost Cc: Matthew Auld Cc: dri-devel@lists.freedesktop.org Signed-off-by: Thomas Hellström Reviewed-by: Matthew Brost Link: https://lore.kernel.org/r/20250502130101.3185-1-thomas.hellstrom@linux.intel.com

ttm: Call shmem_writeout() from ttm_backup_backup_page()

2025-04-07T07:36:49Z

The ->writepage operation is being removed. Since this function exclusively deals with shmem folios, we can call shmem_writeout() to write it. Signed-off-by: "Matthew Wilcox (Oracle)" Link: https://lore.kernel.org/r/20250402150005.2309458-8-willy@infradead.org Signed-off-by: Christian Brauner