leandrof/linux
1
0
Fork 0
forked from Minki/linux
Code Issues Pull Requests Packages Projects Releases Wiki Activity
cc4b8c794f
linux/mm
History
Yang Shi 9bc8039e71 mm: brk: downgrade mmap_sem to read when shrinking 
brk might be used to shrink memory mapping too other than munmap().  So,
it may hold write mmap_sem for long time when shrinking large mapping, as
what commit ("mm: mmap: zap pages with read mmap_sem in munmap")
described.

The brk() will not manipulate vmas anymore after __do_munmap() call for
the mapping shrink use case.  But, it may set mm->brk after __do_munmap(),
which needs hold write mmap_sem.

However, a simple trick can workaround this by setting mm->brk before
__do_munmap().  Then restore the original value if __do_munmap() fails.
With this trick, it is safe to downgrade to read mmap_sem.

So, the same optimization, which downgrades mmap_sem to read for zapping
pages, is also feasible and reasonable to this case.

The period of holding exclusive mmap_sem for shrinking large mapping would
be reduced significantly with this optimization.

[akpm@linux-foundation.org: tweak comment]
[yang.shi@linux.alibaba.com: fix unsigned compare against 0 issue]
  Link: http://lkml.kernel.org/r/1538687672-17795-1-git-send-email-yang.shi@linux.alibaba.com
Link: http://lkml.kernel.org/r/1538067582-60038-2-git-send-email-yang.shi@linux.alibaba.com
Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Laurent Dufour <ldufour@linux.vnet.ibm.com>
Cc: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-10-26 16:26:35 -07:00
..
kasan kernel/memremap, kasan: make ZONE_DEVICE with work with KASAN 2018-08-17 16:20:30 -07:00
backing-dev.c blkcg: delay blkg destruction until after writeback has finished 2018-08-31 14:48:56 -06:00
balloon_compaction.c virtio_balloon: fix deadlock on OOM 2017-11-14 23:57:38 +02:00
bootmem.c docs/mm: bootmem: add overview documentation 2018-08-02 12:17:27 -06:00
cleancache.c mm: use octal not symbolic permissions 2018-06-15 07:55:25 +09:00
cma_debug.c mm/cma: remove unsupported gfp_mask parameter from cma_alloc() 2018-08-17 16:20:32 -07:00
cma.c mm/cma: remove unsupported gfp_mask parameter from cma_alloc() 2018-08-17 16:20:32 -07:00
cma.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
compaction.c psi: pressure stall information for CPU, memory, and IO 2018-10-26 16:26:32 -07:00
debug_page_ref.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
debug.c mm: provide kernel parameter to allow disabling page init poisoning 2018-10-26 16:26:34 -07:00
dmapool.c mm: use octal not symbolic permissions 2018-06-15 07:55:25 +09:00
early_ioremap.c mm/early_ioremap: Fix boot hang with earlyprintk=efi,keep 2017-12-11 14:54:44 +01:00
fadvise.c vfs: implement readahead(2) using POSIX_FADV_WILLNEED 2018-08-30 20:01:32 +02:00
failslab.c mm: use octal not symbolic permissions 2018-06-15 07:55:25 +09:00
filemap.c mm/filemap.c: use vmf_error() 2018-10-26 16:26:35 -07:00
frame_vector.c mm/frame_vector.c: release a semaphore in 'get_vaddr_frames()' 2017-12-14 16:00:48 -08:00
frontswap.c mm: use octal not symbolic permissions 2018-06-15 07:55:25 +09:00
gup_benchmark.c mm/gup_benchmark: fix unsigned comparison to zero in __gup_benchmark_ioctl 2018-10-05 16:32:04 -07:00
gup.c mm: remove unnecessary local variable addr in __get_user_pages_fast() 2018-10-26 16:26:34 -07:00
highmem.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
hmm.c mm: defer ZONE_DEVICE page initialization to the point where we init pgmap 2018-10-26 16:26:34 -07:00
huge_memory.c mm: workingset: tell cache transitions from workingset thrashing 2018-10-26 16:26:32 -07:00
hugetlb_cgroup.c mm: rename page_counter's count/limit into usage/max 2018-06-07 17:34:35 -07:00
hugetlb.c hugetlb: take PMD sharing into account when flushing tlb/caches 2018-10-05 16:32:04 -07:00
hwpoison-inject.c mm/memory_failure: Remove unused trapno from memory_failure 2018-01-23 12:17:42 -06:00
init-mm.c mm: Allocate the mm_cpumask (mm->cpu_bitmap[]) dynamically based on nr_cpu_ids 2018-07-17 09:35:30 +02:00
internal.h mm: Change return type int to vm_fault_t for fault handlers 2018-08-23 18:48:44 -07:00
interval_tree.c mm/interval_tree.c: use vma_pages() helper 2018-01-31 17:18:37 -08:00
Kconfig mm: disable deferred struct page for 32-bit arches 2018-09-20 22:01:11 +02:00
Kconfig.debug mm: clarify CONFIG_PAGE_POISONING and usage 2018-08-22 10:52:44 -07:00
khugepaged.c mm: Change return type int to vm_fault_t for fault handlers 2018-08-23 18:48:44 -07:00
kmemleak-test.c
kmemleak.c kmemleak: add module param to print warnings to dmesg 2018-10-26 16:25:19 -07:00
ksm.c include/linux/compiler*.h: make compiler-*.h mutually exclusive 2018-08-22 17:31:34 -07:00
list_lru.c mm/list_lru: introduce list_lru_shrink_walk_irq() 2018-08-17 16:20:32 -07:00
maccess.c x86/fault: BUG() when uaccess helpers fault on kernel addresses 2018-09-03 15:12:09 +02:00
madvise.c mm: madvise(MADV_DODUMP): allow hugetlbfs pages 2018-10-05 16:32:05 -07:00
Makefile arm64 updates for 4.20: 2018-10-22 17:30:06 +01:00
memblock.c mm: provide kernel parameter to allow disabling page init poisoning 2018-10-26 16:26:34 -07:00
memcontrol.c memcg: remove memcg_kmem_skip_account 2018-10-26 16:26:33 -07:00
memfd.c alloc_file(): switch to passing O_... flags instead of FMODE_... mode 2018-07-12 10:02:57 -04:00
memory_hotplug.c mm/memory_hotplug.c: clean up node_states_check_changes_offline() 2018-10-26 16:26:33 -07:00
memory-failure.c libnvdimm-for-4.19_dax-memory-failure 2018-08-25 18:43:59 -07:00
memory.c mm: convert insert_pfn() to vm_fault_t 2018-10-26 16:25:20 -07:00
mempolicy.c mm/mempolicy.c: use match_string() helper to simplify the code 2018-10-26 16:26:33 -07:00
mempool.c mm/mempool.c: add missing parameter description 2018-08-22 10:52:44 -07:00
memtest.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
migrate.c mm: workingset: tell cache transitions from workingset thrashing 2018-10-26 16:26:32 -07:00
mincore.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
mlock.c dax: remove VM_MIXEDMAP for fsdax and device dax 2018-08-17 16:20:27 -07:00
mm_init.c mm: access zone->node via zone_to_nid() and zone_set_nid() 2018-08-22 10:52:45 -07:00
mmap.c mm: brk: downgrade mmap_sem to read when shrinking 2018-10-26 16:26:35 -07:00
mmu_context.c
mmu_gather.c mm/memory: Move mmu_gather and TLB invalidation code into its own file 2018-09-07 15:19:25 +01:00
mmu_notifier.c Revert "mm, mmu_notifier: annotate mmu notifiers with blockable invalidate callbacks" 2018-10-26 16:25:19 -07:00
mmzone.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
mprotect.c x86/speculation/l1tf: Disallow non privileged high MMIO PROT_NONE mappings 2018-06-20 19:10:01 +02:00
mremap.c mm: mremap: downgrade mmap_sem to read when shrinking 2018-10-26 16:26:35 -07:00
msync.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
nobootmem.c mm/memblock: add a name for memblock flags enumeration 2018-08-02 12:17:27 -06:00
nommu.c mm: provide a fallback for PAGE_KERNEL_EXEC for architectures 2018-08-17 16:20:29 -07:00
oom_kill.c Merge branch 'siginfo-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2018-10-24 11:22:39 +01:00
page_alloc.c mm: defer ZONE_DEVICE page initialization to the point where we init pgmap 2018-10-26 16:26:34 -07:00
page_counter.c memcg: introduce memory.min 2018-06-07 17:34:36 -07:00
page_ext.c mm/page_ext.c: constify lookup_page_ext() argument 2018-08-17 16:20:28 -07:00
page_idle.c mm: use octal not symbolic permissions 2018-06-15 07:55:25 +09:00
page_io.c blkcg: associate a blkg for pages being evicted by swap 2018-09-21 20:29:09 -06:00
page_isolation.c mm, migrate: remove reason argument from new_page_t 2018-04-11 10:28:32 -07:00
page_owner.c mm: use octal not symbolic permissions 2018-06-15 07:55:25 +09:00
page_poison.c mm/page_poison.c: make early_page_poison_param() __init 2018-04-05 21:36:26 -07:00
page_vma_mapped.c mm, page_vma_mapped: Introduce pfn_in_hpage() 2018-01-22 12:15:57 -08:00
page-writeback.c notifier: Remove notifier header file wherever not used 2018-08-30 12:56:40 +02:00
pagewalk.c mm: kernel-doc: add missing parameter descriptions 2018-04-05 21:36:27 -07:00
percpu-internal.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
percpu-km.c percpu: allow select gfp to be passed to underlying allocators 2018-02-18 05:33:01 -08:00
percpu-stats.c treewide: Use array_size() in vmalloc() 2018-06-12 16:19:22 -07:00
percpu-vm.c percpu: allow select gfp to be passed to underlying allocators 2018-02-18 05:33:01 -08:00
percpu.c percpu: stop leaking bitmap metadata blocks 2018-10-07 14:50:12 -07:00
pgtable-generic.c x86/mm: Page size aware flush_tlb_mm_range() 2018-10-09 16:51:11 +02:00
process_vm_access.c mm: docs: add blank lines to silence sphinx "Unexpected indentation" errors 2018-02-06 18:32:48 -08:00
quicklist.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
readahead.c vfs: implement readahead(2) using POSIX_FADV_WILLNEED 2018-08-30 20:01:32 +02:00
rmap.c mm: migration: fix migration of huge PMD shared pages 2018-10-05 16:32:04 -07:00
rodata_test.c mm: fix RODATA_TEST failure "rodata_test: test data was not read only" 2017-10-03 17:54:24 -07:00
shmem.c mm: shmem.c: Correctly annotate new inodes for lockdep 2018-09-20 22:01:11 +02:00
slab_common.c mm, slab: shorten kmalloc cache names for large sizes 2018-10-26 16:26:32 -07:00
slab.c mm, slab: combine kmalloc_caches and kmalloc_dma_caches 2018-10-26 16:26:31 -07:00
slab.h mm: introduce CONFIG_MEMCG_KMEM as combination of CONFIG_MEMCG && !CONFIG_SLOB 2018-08-17 16:20:30 -07:00
slob.c slab: __GFP_ZERO is incompatible with a constructor 2018-06-07 17:34:34 -07:00
slub.c mm, slab: combine kmalloc_caches and kmalloc_dma_caches 2018-10-26 16:26:31 -07:00
sparse-vmemmap.c mm/sparse: delete old sparse_init and enable new one 2018-08-17 16:20:32 -07:00
sparse.c mm: provide kernel parameter to allow disabling page init poisoning 2018-10-26 16:26:34 -07:00
swap_cgroup.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
swap_slots.c mm, swap, get_swap_pages: use entry_size instead of cluster in parameter 2018-08-22 10:52:44 -07:00
swap_state.c mm: workingset: tell cache transitions from workingset thrashing 2018-10-26 16:26:32 -07:00
swap.c mm/swap.c: remove duplicated include 2018-10-26 16:26:33 -07:00
swapfile.c mm/swapfile.c: clear si->swap_map[] in swap_free_cluster() 2018-10-26 16:25:19 -07:00
truncate.c page cache: use xa_lock 2018-04-11 10:28:39 -07:00
usercopy.c usercopy: Allow boot cmdline disabling of hardening 2018-07-04 08:04:52 -07:00
userfaultfd.c userfaultfd: prevent non-cooperative events vs mcopy_atomic races 2018-06-07 17:34:38 -07:00
util.c kvfree(): fix misleading comment 2018-10-26 16:26:33 -07:00
vmacache.c mm: get rid of vmacache_flush_all() entirely 2018-09-13 15:18:04 -10:00
vmalloc.c vfree: add debug might_sleep() 2018-10-26 16:26:33 -07:00
vmpressure.c mm/vmpressure.c: convert to use match_string() helper 2018-06-07 17:34:36 -07:00
vmscan.c mm: zero-seek shrinkers 2018-10-26 16:26:33 -07:00
vmstat.c mm: workingset: add vmstat counter for shadow nodes 2018-10-26 16:26:33 -07:00
workingset.c mm: zero-seek shrinkers 2018-10-26 16:26:33 -07:00
z3fold.c z3fold: fix reclaim lock-ups 2018-05-11 17:28:45 -07:00
zbud.c mm: docs: fix parameter names mismatch 2018-02-06 18:32:48 -08:00
zpool.c mm/zpool.c: zpool_evictable: fix mismatch in parameter name and kernel-doc 2018-02-21 15:35:43 -08:00
zsmalloc.c mm/zsmalloc.c: make several functions and a struct static 2018-08-17 16:20:30 -07:00
zswap.c zswap: re-check zswap_is_full() after do zswap_shrink() 2018-07-26 19:38:03 -07:00