linux/mm
Linus Torvalds 9becb68891 kvmalloc: use vmalloc_huge for vmalloc allocations
Since commit 559089e0a9 ("vmalloc: replace VM_NO_HUGE_VMAP with
VM_ALLOW_HUGE_VMAP"), the use of hugepage mappings for vmalloc is an
opt-in strategy, because it caused a number of problems that weren't
noticed until x86 enabled it too.

One of the issues was fixed by Nick Piggin in commit 3b8000ae18
("mm/vmalloc: huge vmalloc backing pages should be split rather than
compound"), but I'm still worried about page protection issues, and
VM_FLUSH_RESET_PERMS in particular.

However, like the hash table allocation case (commit f2edd118d0:
"page_alloc: use vmalloc_huge for large system hash"), the use of
kvmalloc() should be safe from any such games, since the returned
pointer might be a SLUB allocation, and as such no user should
reasonably be using it in any odd ways.

We also know that the allocations are fairly large, since it falls back
to the vmalloc case only when a kmalloc() fails.  So using a hugepage
mapping seems both safe and relevant.

This patch does show a weakness in the opt-in strategy: since the opt-in
flag is in the 'vm_flags', not the usual gfp_t allocation flags, very
few of the usual interfaces actually expose it.

That's not much of an issue in this case that already used one of the
fairly specialized low-level vmalloc interfaces for the allocation, but
for a lot of other vmalloc() users that might want to opt in, it's going
to be very inconvenient.

We'll either have to fix any compatibility problems, or expose it in the
gfp flags (__GFP_COMP would have made a lot of sense) to allow normal
vmalloc() users to use hugepage mappings.  That said, the cases that
really matter were probably already taken care of by the hash tabel
allocation.

Link: https://lore.kernel.org/all/20220415164413.2727220-1-song@kernel.org/
Link: https://lore.kernel.org/all/CAHk-=whao=iosX1s5Z4SF-ZGa-ebAukJoAdUJFk5SPwnofV+Vg@mail.gmail.com/
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Paul Menzel <pmenzel@molgen.mpg.de>
Cc: Song Liu <songliubraving@fb.com>
Cc: Rick Edgecombe <rick.p.edgecombe@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2022-04-24 10:05:38 -07:00
..
damon mm/damon: prevent activated scheme from sleeping by deactivated schemes 2022-04-01 11:46:09 -07:00
kasan kasan: fix hw tags enablement when KUNIT tests are disabled 2022-04-15 14:49:55 -07:00
kfence mm, kfence: support kmem_dump_obj() for KFENCE objects 2022-04-15 14:49:55 -07:00
backing-dev.c remove congestion tracking framework 2022-03-22 15:57:01 -07:00
balloon_compaction.c mm/balloon_compaction: make balloon page compaction callbacks static 2022-03-28 16:52:57 -04:00
bootmem_info.c bootmem: Use page->index instead of page->freelist 2022-01-06 12:27:03 +01:00
cma_debug.c
cma_sysfs.c
cma.c mm/cma: provide option to opt out from exposing pages on activation failure 2022-03-22 15:57:09 -07:00
cma.h mm/cma: provide option to opt out from exposing pages on activation failure 2022-03-22 15:57:09 -07:00
compaction.c mm: compaction: fix compiler warning when CONFIG_COMPACTION=n 2022-04-15 14:49:55 -07:00
debug_page_ref.c
debug_vm_pgtable.c mm/debug_vm_pgtable: remove pte entry from the page table 2022-02-04 09:25:04 -08:00
debug.c mm: unexport page_init_poison 2022-03-24 19:06:45 -07:00
dmapool.c mm/dmapool.c: revert "make dma pool to use kmalloc_node" 2022-01-15 16:30:28 +02:00
early_ioremap.c mm/early_ioremap: declare early_memremap_pgprot_adjust() 2022-03-22 15:57:11 -07:00
fadvise.c remove inode_congested() 2022-03-22 15:57:01 -07:00
failslab.c
filemap.c tmpfs: fix regressions from wider use of ZERO_PAGE 2022-04-15 14:49:54 -07:00
folio-compat.c mm/rmap: Convert rmap_walk() to take a folio 2022-03-21 13:01:35 -04:00
frontswap.c frontswap: remove support for multiple ops 2022-01-22 08:33:38 +02:00
gup_test.c
gup_test.h
gup.c mm/munlock: add lru_add_drain() to fix memcg_stat_test 2022-04-01 11:46:09 -07:00
highmem.c highmem: fix checks in __kmap_local_sched_{in,out} 2022-04-08 14:20:36 -10:00
hmm.c mm/hmm.c: remove unneeded local variable ret 2022-03-22 15:57:12 -07:00
huge_memory.c mm/huge_memory: Avoid calling pmd_page() on a non-leaf PMD 2022-04-07 09:43:41 -04:00
hugetlb_cgroup.c hugetlb: add hugetlb.*.numa_stat file 2022-01-15 16:30:29 +02:00
hugetlb_vmemmap.c mm: hugetlb: replace hugetlb_free_vmemmap_enabled with a static_key 2022-03-22 15:57:08 -07:00
hugetlb_vmemmap.h
hugetlb.c mm/hwpoison: fix race between hugetlb free/demotion and memory_failure_hugetlb() 2022-04-21 20:01:09 -07:00
hwpoison-inject.c mm/hwpoison: avoid the impact of hwpoison_filter() return value on mce handler 2022-03-22 15:57:07 -07:00
init-mm.c kernel/fork: Initialize mm's PASID 2022-02-14 19:51:47 +01:00
internal.h mm/munlock: protect the per-CPU pagevec by a local_lock_t 2022-04-01 11:46:09 -07:00
interval_tree.c
io-mapping.c
ioremap.c
Kconfig mm: generalize ARCH_HAS_FILTER_PGPROT 2022-03-24 19:06:51 -07:00
Kconfig.debug mm: page table check 2022-01-15 16:30:28 +02:00
khugepaged.c mm/khugepaged: remove reuse_swap_page() usage 2022-03-24 19:06:51 -07:00
kmemleak.c mm: kmemleak: take a full lowmem check in kmemleak_*_phys() 2022-04-15 14:49:56 -07:00
ksm.c Folio changes for 5.18 2022-03-22 17:03:12 -07:00
list_lru.c mm/list_lru.c: revert "mm/list_lru: optimize memcg_reparent_list_lru_node()" 2022-04-08 14:20:36 -10:00
maccess.c asm-generic updates for 5.18 2022-03-23 18:03:08 -07:00
madvise.c Revert "mm: madvise: skip unmapped vma holes passed to process_madvise" 2022-04-01 11:46:09 -07:00
Makefile mm: move the migrate_vma_* device migration code into its own file 2022-03-03 12:47:33 -05:00
mapping_dirty_helpers.c mm: move tlb_flush_pending inline helpers to mm_inline.h 2022-01-15 16:30:27 +02:00
memblock.c memblock: test suite and a small cleanup 2022-03-27 13:36:06 -07:00
memcontrol.c memcg: sync flush only if periodic flush is delayed 2022-04-21 20:01:09 -07:00
memfd.c memfd: fix F_SEAL_WRITE after shmem huge page allocated 2022-03-05 11:08:32 -08:00
memory_hotplug.c Folio changes for 5.18 2022-03-22 17:03:12 -07:00
memory-failure.c mm/memory-failure.c: skip huge_zero_page in memory_failure() 2022-04-21 20:01:09 -07:00
memory.c mm,hwpoison: unmap poisoned page before invalidation 2022-04-01 11:46:09 -07:00
mempolicy.c Merge branch 'akpm' (patches from Andrew) 2022-04-08 14:31:41 -10:00
mempool.c
memremap.c mm: delete __ClearPageWaiters() 2022-03-24 19:06:45 -07:00
memtest.c
migrate_device.c mm/migrate: Convert remove_migration_ptes() to folios 2022-03-21 13:01:35 -04:00
migrate.c mm: migrate: use thp_order instead of HPAGE_PMD_ORDER for new page allocation. 2022-04-08 14:20:36 -10:00
mincore.c
mlock.c mm/munlock: protect the per-CPU pagevec by a local_lock_t 2022-04-01 11:46:09 -07:00
mm_init.c
mmap_lock.c
mmap.c mm, hugetlb: allow for "high" userspace addresses 2022-04-21 20:01:09 -07:00
mmu_gather.c mm: move tlb_flush_pending inline helpers to mm_inline.h 2022-01-15 16:30:27 +02:00
mmu_notifier.c mm/mmu_notifier.c: fix race in mmu_interval_notifier_remove() 2022-04-21 20:01:10 -07:00
mmzone.c Folio changes for 5.18 2022-03-22 17:03:12 -07:00
mprotect.c memory tiering: skip to scan fast memory 2022-03-22 15:57:09 -07:00
mremap.c mmmremap.c: avoid pointless invalidate_range_start/end on mremap(old_size=0) 2022-04-08 14:20:36 -10:00
msync.c
nommu.c Merge branch 'akpm' (patches from Andrew) 2021-11-06 14:08:17 -07:00
oom_kill.c oom_kill.c: futex: delay the OOM reaper to allow time for proper futex cleanup 2022-04-21 20:01:10 -07:00
page_alloc.c page_alloc: use vmalloc_huge for large system hash 2022-04-24 10:00:54 -07:00
page_counter.c mm/page_counter: remove an incorrect call to propagate_protected_usage() 2022-01-15 16:30:27 +02:00
page_ext.c mm: make some vars and functions static or __init 2022-01-15 16:30:31 +02:00
page_idle.c mm/rmap: Constify the rmap_walk_control argument 2022-03-21 13:01:35 -04:00
page_io.c mm: fix unexpected zeroed page mapping with zram swap 2022-04-15 14:49:55 -07:00
page_isolation.c Revert "mm/page_isolation: unset migratetype directly for non Buddy page" 2022-02-04 09:25:04 -08:00
page_owner.c mm/page_owner.c: record tgid 2022-03-24 19:06:44 -07:00
page_poison.c
page_reporting.c
page_reporting.h
page_table_check.c mm/page_table_check.c: use strtobool for param parsing 2022-03-22 15:57:11 -07:00
page_vma_mapped.c mm/rmap: Fix handling of hugetlbfs pages in page_vma_mapped_walk 2022-04-07 10:11:20 -04:00
page-writeback.c mm: warn on deleting redirtied only if accounted 2022-03-24 19:06:51 -07:00
pagewalk.c
percpu-internal.h mm: memcg/percpu: account extra objcg space to memory cgroups 2022-01-15 16:30:31 +02:00
percpu-km.c
percpu-stats.c mm: use vmalloc_array and vcalloc for array allocations 2022-03-08 09:30:46 -05:00
percpu-vm.c
percpu.c bitmap patches for 5.17-rc1 2022-01-23 06:20:44 +02:00
pgalloc-track.h
pgtable-generic.c mm: move tlb_flush_pending inline helpers to mm_inline.h 2022-01-15 16:30:27 +02:00
process_vm_access.c
ptdump.c mm: sparsemem: use page table lock to protect kernel pmd operations 2022-03-22 15:57:08 -07:00
readahead.c readahead: Update comments 2022-04-01 14:40:42 -04:00
rmap.c mm/munlock: protect the per-CPU pagevec by a local_lock_t 2022-04-01 11:46:09 -07:00
rodata_test.c
secretmem.c mm/secretmem: fix panic when growing a memfd_secret 2022-04-15 14:49:54 -07:00
shmem.c tmpfs: fix regressions from wider use of ZERO_PAGE 2022-04-15 14:49:54 -07:00
shuffle.c
shuffle.h
slab_common.c mm, kfence: support kmem_dump_obj() for KFENCE objects 2022-04-15 14:49:55 -07:00
slab.c mm, kfence: support kmem_dump_obj() for KFENCE objects 2022-04-15 14:49:55 -07:00
slab.h mm, kfence: support kmem_dump_obj() for KFENCE objects 2022-04-15 14:49:55 -07:00
slob.c mm, kfence: support kmem_dump_obj() for KFENCE objects 2022-04-15 14:49:55 -07:00
slub.c mm, kfence: support kmem_dump_obj() for KFENCE objects 2022-04-15 14:49:55 -07:00
sparse-vmemmap.c mm: sparsemem: move vmemmap related to HugeTLB to CONFIG_HUGETLB_PAGE_FREE_VMEMMAP 2022-03-22 15:57:08 -07:00
sparse.c mm/sparse: make mminit_validate_memmodel_limits() static 2022-03-22 15:57:05 -07:00
swap_cgroup.c mm: use vmalloc_array and vcalloc for array allocations 2022-03-08 09:30:46 -05:00
swap_slots.c treewide: Add missing includes masked by cgroup -> bpf dependency 2021-12-03 10:58:13 -08:00
swap_state.c Filesystem folio changes for 5.18 2022-03-22 18:26:56 -07:00
swap.c mm/munlock: protect the per-CPU pagevec by a local_lock_t 2022-04-01 11:46:09 -07:00
swapfile.c mm/swapfile: remove stale reuse_swap_page() 2022-03-24 19:06:51 -07:00
truncate.c Filesystem folio changes for 5.18 2022-03-22 18:26:56 -07:00
usercopy.c Merge branch 'akpm' (patches from Andrew) 2022-03-22 16:11:53 -07:00
userfaultfd.c userfaultfd: mark uffd_wp regardless of VM_WRITE flag 2022-04-21 20:01:09 -07:00
util.c kvmalloc: use vmalloc_huge for vmalloc allocations 2022-04-24 10:05:38 -07:00
vmacache.c
vmalloc.c mm/vmalloc: huge vmalloc backing pages should be split rather than compound 2022-04-22 09:20:16 -07:00
vmpressure.c
vmscan.c Folio changes for 5.18 2022-03-22 17:03:12 -07:00
vmstat.c mm: only re-generate demotion targets when a numa node changes its N_CPU state 2022-03-22 15:57:11 -07:00
workingset.c memcg: sync flush only if periodic flush is delayed 2022-04-21 20:01:09 -07:00
z3fold.c
zbud.c
zpool.c zpool: remove the list of pools_head 2022-01-15 16:30:31 +02:00
zsmalloc.c zsmalloc: replace get_cpu_var with local_lock 2022-01-22 08:33:37 +02:00
zswap.c mm/zswap.c: allow handling just same-value filled pages 2022-03-22 15:57:11 -07:00