kernel/linux.git/include/linux/gfp.h, branch v7.0-rc7

Merge tag 'mm-hotfixes-stable-2026-02-26-14-14' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2026-02-26T23:27:41+00:00

Pull misc fixes from Andrew Morton: "12 hotfixes. 7 are cc:stable. 8 are for MM. All are singletons - please see the changelogs for details" * tag 'mm-hotfixes-stable-2026-02-26-14-14' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: MAINTAINERS: update Yosry Ahmed's email address mailmap: add entry for Daniele Alessandrelli mm: fix NULL NODE_DATA dereference for memoryless nodes on boot mm/tracing: rss_stat: ensure curr is false from kthread context mm/kfence: fix KASAN hardware tag faults during late enablement mm/damon/core: disallow non-power of two min_region_sz Squashfs: check metadata block offset is within range MAINTAINERS, mailmap: update e-mail address for Vlastimil Babka liveupdate: luo_file: remember retrieve() status mm: thp: deny THP for files on anonymous inodes mm: change vma_alloc_folio_noprof() macro to inline function mm/kfence: disable KFENCE upon KASAN HW tags enablement

mm: change vma_alloc_folio_noprof() macro to inline function

2026-02-24T19:13:26+00:00

In a few rare configurations with extra warnings eanbled, the new drm_pagemap_migrate_populate_ram_pfn() calls vma_alloc_folio_noprof() but that does not use all the arguments, leading to a harmless warning: drivers/gpu/drm/drm_pagemap.c: In function 'drm_pagemap_migrate_populate_ram_pfn': drivers/gpu/drm/drm_pagemap.c:701:63: error: parameter 'addr' set but not used [-Werror=unused-but-set-parameter=] 701 | unsigned long addr) | ~~~~~~~~~~~~~~^~~~ Replace the macro with an inline function so the compiler can see how the argument would be used, but is still able to optimize out the assignments. Link: https://lkml.kernel.org/r/20260216121751.2378374-1-arnd@kernel.org Signed-off-by: Arnd Bergmann Reviewed-by: Lorenzo Stoakes Acked-by: Zi Yan Reviewed-by: Suren Baghdasaryan Cc: Alexei Starovoitov Cc: Brendan Jackman Cc: David Hildenbrand Cc: Johannes Weiner Cc: Joshua Hahn Cc: Kefeng Wang Cc: Liam Howlett Cc: Michal Hocko Cc: Mike Rapoport Cc: Shakeel Butt Cc: Vlastimil Babka Signed-off-by: Andrew Morton

default_gfp(): avoid using the "newfangled" __VA_OPT__ trick

2026-02-23T17:33:08+00:00

The default_gfp() helper that I added is not wrong, but it turns out that it causes unnecessary headaches for 'sparse' which doesn't support the use of __VA_OPT__ (introduced in C++20 and C23, and supported by gcc and clang for a long time). We do already use __VA_OPT__ in some other cases in the kernel (drm/xe and btrfs), but it has been fairly limited. Now it triggers for pretty much everything, and sparse ends up not working at all. We can use the traditional gcc ',##__VA_ARGS__' syntax instead: it may not be the "C standard" way and is slightly less natural in this context, but it is the traditional model for this and avoids the sparse problem. Reported-and-tested-by: Ricardo Ribalda Reported-and-tested-by: Richard Fitzgerald Reported-by: Ben Dooks Fixes: e19e1b480ac7 ("add default_gfp() helper macro and use it in the new *alloc_obj() helpers") Signed-off-by: Linus Torvalds

add default_gfp() helper macro and use it in the new *alloc_obj() helpers

2026-02-22T01:09:50+00:00

Most simple allocations use GFP_KERNEL, and with the new allocation helpers being introduced, let's just take advantage of that to simplify that default case. It's a numbers game: git grep 'alloc_obj(' | sed 's/.*$GFP_[_A-Z]*$.*/\1/' | sort | uniq -c | sort -n | tail shows that about 90% of all those new allocator instances just use that standard GFP_KERNEL. Those helpers are already macros, and we can easily just make it be the default case when the gfp argument is missing. And yes, we could do that for all the legacy interfaces too, but let's keep it to just the new ones at least for now, since those all got converted recently anyway, so this is not any "extra" noise outside of that limited conversion. And, in fact, I want to do this before doing the -rc1 release, exactly so that we don't get extra merge conflicts. Signed-off-by: Linus Torvalds

mm: page_alloc: add alloc_contig_frozen_{range,pages}()

2026-01-27T04:02:28+00:00

In order to allocate given range of pages or allocate compound pages without incrementing their refcount, adding two new helper alloc_contig_frozen_{range,pages}() which may be beneficial to some users (eg hugetlb). The new alloc_contig_{range,pages} only take !__GFP_COMP gfp now, and the free_contig_range() is refactored to only free non-compound pages, the only caller to free compound pages in cma_free_folio() is changed accordingly, and the free_contig_frozen_range() is provided to match the alloc_contig_frozen_range(), which is used to free frozen pages. Link: https://lkml.kernel.org/r/20260109093136.1491549-5-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang Reviewed-by: Zi Yan Reviewed-by: Sidhartha Kumar Cc: Brendan Jackman Cc: David Hildenbrand Cc: Jane Chu Cc: Johannes Weiner Cc: Matthew Wilcox (Oracle) Cc: Muchun Song Cc: Oscar Salvador Cc: Vlastimil Babka Cc: Claudiu Beznea Cc: Mark Brown Signed-off-by: Andrew Morton

mm: debug_vm_pgtable: add debug_vm_pgtable_free_huge_page()

2026-01-27T04:02:27+00:00

Patch series "mm: hugetlb: allocate frozen gigantic folio", v6. Introduce alloc_contig_frozen_pages() and cma_alloc_frozen_compound() which avoid atomic operation about page refcount, and then convert to allocate frozen gigantic folio by the new helpers in hugetlb to cleanup the alloc_gigantic_folio(). This patch (of 6): Add a new helper to free huge page to be consistency to debug_vm_pgtable_alloc_huge_page(), and use HPAGE_PUD_ORDER instead of open-code. Also move the free_contig_range() under CONFIG_ALLOC_CONTIG since all caller are built with CONFIG_ALLOC_CONTIG. Link: https://lkml.kernel.org/r/20260109093136.1491549-2-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang Acked-by: David Hildenbrand Reviewed-by: Zi Yan Reviewed-by: Muchun Song Reviewed-by: Sidhartha Kumar Cc: Brendan Jackman Cc: Jane Chu Cc: Johannes Weiner Cc: Matthew Wilcox (Oracle) Cc: Oscar Salvador Cc: Vlastimil Babka Cc: Claudiu Beznea Cc: Mark Brown Signed-off-by: Andrew Morton

mm/page_alloc: refactor the initial compaction handling

2026-01-27T04:02:23+00:00

The initial direct compaction done in some cases in __alloc_pages_slowpath() stands out from the main retry loop of reclaim + compaction. We can simplify this by instead skipping the initial reclaim attempt via a new local variable compact_first, and handle the compact_prority as necessary to match the original behavior. No functional change intended. Link: https://lkml.kernel.org/r/20260106-thp-thisnode-tweak-v3-2-f5d67c21a193@suse.cz Signed-off-by: Vlastimil Babka Suggested-by: Johannes Weiner Reviewed-by: Joshua Hahn Acked-by: Michal Hocko Cc: Brendan Jackman Cc: David Hildenbrand (Red Hat) Cc: David Rientjes Cc: Liam Howlett Cc: Lorenzo Stoakes Cc: Mike Rapoport Cc: Pedro Falcato Cc: Suren Baghdasaryan Cc: Zi Yan Signed-off-by: Andrew Morton

mm/page_alloc/vmstat: simplify refresh_cpu_vm_stats change detection

2025-11-17T01:28:04+00:00

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 Reviewed-by: Vlastimil Babka Reviewed-by: SeongJae Park Cc: Brendan Jackman Cc: Chris Mason Cc: Johannes Weiner Cc: "Kirill A. Shutemov" Cc: Michal Hocko Cc: Suren Baghdasaryan Cc: Zi Yan Signed-off-by: Andrew Morton

kho: allocate metadata directly from the buddy allocator

2025-11-10T05:19:42+00:00

KHO allocates metadata for its preserved memory map using the slab allocator via kzalloc(). This metadata is temporary and is used by the next kernel during early boot to find preserved memory. A problem arises when KFENCE is enabled. kzalloc() calls can be randomly intercepted by kfence_alloc(), which services the allocation from a dedicated KFENCE memory pool. This pool is allocated early in boot via memblock. When booting via KHO, the memblock allocator is restricted to a "scratch area", forcing the KFENCE pool to be allocated within it. This creates a conflict, as the scratch area is expected to be ephemeral and overwriteable by a subsequent kexec. If KHO metadata is placed in this KFENCE pool, it leads to memory corruption when the next kernel is loaded. To fix this, modify KHO to allocate its metadata directly from the buddy allocator instead of slab. Link: https://lkml.kernel.org/r/20251021000852.2924827-4-pasha.tatashin@soleen.com Fixes: fc33e4b44b27 ("kexec: enable KHO support for memory preservation") Signed-off-by: Pasha Tatashin Reviewed-by: Pratyush Yadav Reviewed-by: Mike Rapoport (Microsoft) Reviewed-by: David Matlack Cc: Alexander Graf Cc: Christian Brauner Cc: Jason Gunthorpe Cc: Jonathan Corbet Cc: Masahiro Yamada Cc: Miguel Ojeda Cc: Randy Dunlap Cc: Samiullah Khawaja Cc: Tejun Heo Cc: Signed-off-by: Andrew Morton

mm: Allow GFP_ACCOUNT to be used in alloc_pages_nolock().

2025-09-29T07:42:35+00:00

Change alloc_pages_nolock() to default to __GFP_COMP when allocating pages, since upcoming reentrant alloc_slab_page() needs __GFP_COMP. Also allow __GFP_ACCOUNT flag to be specified, since most of BPF infra needs __GFP_ACCOUNT except BPF streams. Reviewed-by: Vlastimil Babka Signed-off-by: Alexei Starovoitov Reviewed-by: Shakeel Butt Reviewed-by: Harry Yoo Signed-off-by: Vlastimil Babka