user/sven/linux.git/include/linux/gfp.h, branch v6.16.1

mm: rename try_alloc_pages() to alloc_pages_nolock()

2025-05-22T21:55:37Z

The "try_" prefix is confusing, since it made people believe that try_alloc_pages() is analogous to spin_trylock() and NULL return means EAGAIN. This is not the case. If it returns NULL there is no reason to call it again. It will most likely return NULL again. Hence rename it to alloc_pages_nolock() to make it symmetrical to free_pages_nolock() and document that NULL means ENOMEM. Link: https://lkml.kernel.org/r/20250517003446.60260-1-alexei.starovoitov@gmail.com Signed-off-by: Alexei Starovoitov Acked-by: Vlastimil Babka Acked-by: Johannes Weiner Reviewed-by: Shakeel Butt Acked-by: Harry Yoo Cc: Andrii Nakryiko Cc: Kumar Kartikeya Dwivedi Cc: Michal Hocko Cc: Peter Zijlstra Cc: Sebastian Andrzej Siewior Cc: Steven Rostedt Signed-off-by: Andrew Morton

mm: Fix the flipped condition in gfpflags_allow_spinning()

2025-03-15T18:18:19Z

The function gfpflags_allow_spinning() has a bug that makes it return the opposite result than intended. This could contribute to deadlocks as usage profilerates, for now it was noticed as a performance regression due to try_charge_memcg() not refilling memcg stock when it could. Fix the flipped condition. Fixes: 97769a53f117 ("mm, bpf: Introduce try_alloc_pages() for opportunistic page allocation") Reported-by: kernel test robot Acked-by: Shakeel Butt Signed-off-by: Vlastimil Babka Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20250310124017.187-1-alexei.starovoitov@gmail.com Closes: https://lore.kernel.org/oe-lkp/202503101254.cfd454df-lkp@intel.com Signed-off-by: Alexei Starovoitov

mm, bpf: Introduce free_pages_nolock()

2025-02-27T17:36:18Z

Introduce free_pages_nolock() that can free pages without taking locks. It relies on trylock and can be called from any context. Since spin_trylock() cannot be used in PREEMPT_RT from hard IRQ or NMI it uses lockless link list to stash the pages which will be freed by subsequent free_pages() from good context. Do not use llist unconditionally. BPF maps continuously allocate/free, so we cannot unconditionally delay the freeing to llist. When the memory becomes free make it available to the kernel and BPF users right away if possible, and fallback to llist as the last resort. Acked-by: Vlastimil Babka Acked-by: Sebastian Andrzej Siewior Reviewed-by: Shakeel Butt Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/r/20250222024427.30294-4-alexei.starovoitov@gmail.com Signed-off-by: Alexei Starovoitov

mm, bpf: Introduce try_alloc_pages() for opportunistic page allocation

2025-02-27T17:32:27Z

Tracing BPF programs execute from tracepoints and kprobes where running context is unknown, but they need to request additional memory. The prior workarounds were using pre-allocated memory and BPF specific freelists to satisfy such allocation requests. Instead, introduce gfpflags_allow_spinning() condition that signals to the allocator that running context is unknown. Then rely on percpu free list of pages to allocate a page. try_alloc_pages() -> get_page_from_freelist() -> rmqueue() -> rmqueue_pcplist() will spin_trylock to grab the page from percpu free list. If it fails (due to re-entrancy or list being empty) then rmqueue_bulk()/rmqueue_buddy() will attempt to spin_trylock zone->lock and grab the page from there. spin_trylock() is not safe in PREEMPT_RT when in NMI or in hard IRQ. Bailout early in such case. The support for gfpflags_allow_spinning() mode for free_page and memcg comes in the next patches. This is a first step towards supporting BPF requirements in SLUB and getting rid of bpf_mem_alloc. That goal was discussed at LSFMM: https://lwn.net/Articles/974138/ Acked-by: Michal Hocko Acked-by: Vlastimil Babka Acked-by: Sebastian Andrzej Siewior Reviewed-by: Shakeel Butt Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/r/20250222024427.30294-3-alexei.starovoitov@gmail.com Signed-off-by: Alexei Starovoitov

mm: alloc_pages_bulk: rename API

2025-01-26T04:22:31Z

The previous commit removed the page_list argument from alloc_pages_bulk_noprof() along with the alloc_pages_bulk_list() function. Now that only the *_array() flavour of the API remains, we can do the following renaming (along with the _noprof() ones): alloc_pages_bulk_array -> alloc_pages_bulk alloc_pages_bulk_array_mempolicy -> alloc_pages_bulk_mempolicy alloc_pages_bulk_array_node -> alloc_pages_bulk_node Link: https://lkml.kernel.org/r/275a3bbc0be20fbe9002297d60045e67ab3d4ada.1734991165.git.luizcap@redhat.com Signed-off-by: Luiz Capitulino Acked-by: David Hildenbrand Cc: Matthew Wilcox (Oracle) Cc: Mel Gorman Cc: Yunsheng Lin Signed-off-by: Andrew Morton

mm: alloc_pages_bulk_noprof: drop page_list argument

2025-01-26T04:22:31Z

Patch series "mm: alloc_pages_bulk: small API refactor", v2. Today, alloc_pages_bulk_noprof() supports two arguments to return allocated pages: a linked list and an array. There are also higher level APIs for both. However, the linked list API has apparently never been used. So, this series removes it along with the list API and also refactors the remaining API naming for consistency. This patch (of 2): commit 387ba26fb1cb ("mm/page_alloc: add a bulk page allocator") added __alloc_pages_bulk() along with the page_list argument. The next commit 0f87d9d30f21 ("mm/page_alloc: add an array-based interface to the bulk page allocator") added the array-based argument. As it turns out, the page_list argument has no users in the current tree (if it ever had any). Dropping it allows for a slight simplification and eliminates some unnecessary checks, now that page_array is required. Also, note that the removal of the page_list argument was proposed before in the thread below, where Matthew Wilcox mentions that: """ Iterating a linked list is _expensive_. It is about 10x quicker to iterate an array than a linked list. """ (https://lore.kernel.org/linux-mm/20231025093254.xvomlctwhcuerzky@techsingularity.net) Link: https://lkml.kernel.org/r/cover.1734991165.git.luizcap@redhat.com Link: https://lkml.kernel.org/r/f1c75db91d08cafd211eca6a3b199b629d4ffe16.1734991165.git.luizcap@redhat.com Signed-off-by: Luiz Capitulino Acked-by: David Hildenbrand Cc: Matthew Wilcox (Oracle) Cc: Mel Gorman Cc: Yunsheng Lin Signed-off-by: Andrew Morton

mm: make alloc_pages_mpol() static

2025-01-14T06:40:31Z

All callers outside mempolicy.c now use folio_alloc_mpol() thanks to Kefeng's cleanups, so we can remove this as a visible symbol. And also remove the alloc_hooks for alloc_pages_mpol(), since all users in mempolicy.c are using the nonprof version. Link: https://lkml.kernel.org/r/20241125210149.2976098-3-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) Reviewed-by: Zi Yan Acked-by: David Hildenbrand Reviewed-by: Vlastimil Babka Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com> Cc: Mel Gorman Cc: Miaohe Lin Cc: Muchun Song Cc: William Kucharski Signed-off-by: Andrew Morton

Merge tag 'mm-stable-2024-11-18-19-27' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2024-11-23T17:58:07Z

Pull MM updates from Andrew Morton: - The series "zram: optimal post-processing target selection" from Sergey Senozhatsky improves zram's post-processing selection algorithm. This leads to improved memory savings. - Wei Yang has gone to town on the mapletree code, contributing several series which clean up the implementation: - "refine mas_mab_cp()" - "Reduce the space to be cleared for maple_big_node" - "maple_tree: simplify mas_push_node()" - "Following cleanup after introduce mas_wr_store_type()" - "refine storing null" - The series "selftests/mm: hugetlb_fault_after_madv improvements" from David Hildenbrand fixes this selftest for s390. - The series "introduce pte_offset_map_{ro|rw}_nolock()" from Qi Zheng implements some rationaizations and cleanups in the page mapping code. - The series "mm: optimize shadow entries removal" from Shakeel Butt optimizes the file truncation code by speeding up the handling of shadow entries. - The series "Remove PageKsm()" from Matthew Wilcox completes the migration of this flag over to being a folio-based flag. - The series "Unify hugetlb into arch_get_unmapped_area functions" from Oscar Salvador implements a bunch of consolidations and cleanups in the hugetlb code. - The series "Do not shatter hugezeropage on wp-fault" from Dev Jain takes away the wp-fault time practice of turning a huge zero page into small pages. Instead we replace the whole thing with a THP. More consistent cleaner and potentiall saves a large number of pagefaults. - The series "percpu: Add a test case and fix for clang" from Andy Shevchenko enhances and fixes the kernel's built in percpu test code. - The series "mm/mremap: Remove extra vma tree walk" from Liam Howlett optimizes mremap() by avoiding doing things which we didn't need to do. - The series "Improve the tmpfs large folio read performance" from Baolin Wang teaches tmpfs to copy data into userspace at the folio size rather than as individual pages. A 20% speedup was observed. - The series "mm/damon/vaddr: Fix issue in damon_va_evenly_split_region()" fro Zheng Yejian fixes DAMON splitting. - The series "memcg-v1: fully deprecate charge moving" from Shakeel Butt removes the long-deprecated memcgv2 charge moving feature. - The series "fix error handling in mmap_region() and refactor" from Lorenzo Stoakes cleanup up some of the mmap() error handling and addresses some potential performance issues. - The series "x86/module: use large ROX pages for text allocations" from Mike Rapoport teaches x86 to use large pages for read-only-execute module text. - The series "page allocation tag compression" from Suren Baghdasaryan is followon maintenance work for the new page allocation profiling feature. - The series "page->index removals in mm" from Matthew Wilcox remove most references to page->index in mm/. A slow march towards shrinking struct page. - The series "damon/{self,kunit}tests: minor fixups for DAMON debugfs interface tests" from Andrew Paniakin performs maintenance work for DAMON's self testing code. - The series "mm: zswap swap-out of large folios" from Kanchana Sridhar improves zswap's batching of compression and decompression. It is a step along the way towards using Intel IAA hardware acceleration for this zswap operation. - The series "kasan: migrate the last module test to kunit" from Sabyrzhan Tasbolatov completes the migration of the KASAN built-in tests over to the KUnit framework. - The series "implement lightweight guard pages" from Lorenzo Stoakes permits userapace to place fault-generating guard pages within a single VMA, rather than requiring that multiple VMAs be created for this. Improved efficiencies for userspace memory allocators are expected. - The series "memcg: tracepoint for flushing stats" from JP Kobryn uses tracepoints to provide increased visibility into memcg stats flushing activity. - The series "zram: IDLE flag handling fixes" from Sergey Senozhatsky fixes a zram buglet which potentially affected performance. - The series "mm: add more kernel parameters to control mTHP" from Maíra Canal enhances our ability to control/configuremultisize THP from the kernel boot command line. - The series "kasan: few improvements on kunit tests" from Sabyrzhan Tasbolatov has a couple of fixups for the KASAN KUnit tests. - The series "mm/list_lru: Split list_lru lock into per-cgroup scope" from Kairui Song optimizes list_lru memory utilization when lockdep is enabled. * tag 'mm-stable-2024-11-18-19-27' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (215 commits) cma: enforce non-zero pageblock_order during cma_init_reserved_mem() mm/kfence: add a new kunit test test_use_after_free_read_nofault() zram: fix NULL pointer in comp_algorithm_show() memcg/hugetlb: add hugeTLB counters to memcg vmstat: call fold_vm_zone_numa_events() before show per zone NUMA event mm: mmap_lock: check trace_mmap_lock_$type_enabled() instead of regcount zram: ZRAM_DEF_COMP should depend on ZRAM MAINTAINERS/MEMORY MANAGEMENT: add document files for mm Docs/mm/damon: recommend academic papers to read and/or cite mm: define general function pXd_init() kmemleak: iommu/iova: fix transient kmemleak false positive mm/list_lru: simplify the list_lru walk callback function mm/list_lru: split the lock to per-cgroup scope mm/list_lru: simplify reparenting and initial allocation mm/list_lru: code clean up for reparenting mm/list_lru: don't export list_lru_add mm/list_lru: don't pass unnecessary key parameters kasan: add kunit tests for kmalloc_track_caller, kmalloc_node_track_caller kasan: change kasan_atomics kunit test as KUNIT_CASE_SLOW kasan: use EXPORT_SYMBOL_IF_KUNIT to export symbols ...

mm: move the page fragment allocator from page_alloc into its own file

2024-11-11T18:56:26Z

Inspired by [1], move the page fragment allocator from page_alloc into its own c file and header file, as we are about to make more change for it to replace another page_frag implementation in sock.c As this patchset is going to replace 'struct page_frag' with 'struct page_frag_cache' in sched.h, including page_frag_cache.h in sched.h has a compiler error caused by interdependence between mm_types.h and mm.h for asm-offsets.c, see [2]. So avoid the compiler error by moving 'struct page_frag_cache' to mm_types_task.h as suggested by Alexander, see [3]. 1. https://lore.kernel.org/all/20230411160902.4134381-3-dhowells@redhat.com/ 2. https://lore.kernel.org/all/15623dac-9358-4597-b3ee-3694a5956920@gmail.com/ 3. https://lore.kernel.org/all/CAKgT0UdH1yD=LSCXFJ=YM_aiA4OomD-2wXykO42bizaWMt_HOA@mail.gmail.com/ CC: David Howells CC: Linux-MM Signed-off-by: Yunsheng Lin Acked-by: Andrew Morton Reviewed-by: Alexander Duyck Link: https://patch.msgid.link/20241028115343.3405838-3-linyunsheng@huawei.com Signed-off-by: Jakub Kicinski

mm: remove unused hugepage for vma_alloc_folio()

2024-11-07T04:11:12Z

The hugepage parameter was deprecated since commit ddc1a5cbc05d ("mempolicy: alloc_pages_mpol() for NUMA policy without vma"), for PMD-sized THP, it still tries only preferred node if possible in vma_alloc_folio() by checking the order of the folio allocation. Link: https://lkml.kernel.org/r/20241010061556.1846751-1-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang Acked-by: David Hildenbrand Reviewed-by: Zi Yan Reviewed-by: Barry Song Cc: Hugh Dickins Cc: Matthew Wilcox Cc: Ryan Roberts Signed-off-by: Andrew Morton