The patch titled
Subject: mm, doc: cleanup and clarify munmap behavior for hugetlb memory fix
has been added to the -mm tree. Its filename is
mm-doc-cleanup-and-clarify-munmap-behavior-for-hugetlb-memory-fix.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-doc-cleanup-and-clarify-munmap-behavior-for-hugetlb-memory-fix.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-doc-cleanup-and-clarify-munmap-behavior-for-hugetlb-memory-fix.patch
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From: David Rientjes <rientjes@xxxxxxxxxx>
Subject: mm, doc: cleanup and clarify munmap behavior for hugetlb memory fix
Don't only specify munmap(2) behavior with respect the hugetlb memory, all
other syscalls get naturally aligned to the native page size of the
processor. Rather, pick out munmap(2) as a specific example.
Signed-off-by: David Rientjes <rientjes@xxxxxxxxxx>
Acked-by: Hugh Dickins <hughd@xxxxxxxxxx>
Acked-by: Hillf Danton <hillf.zj@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
Documentation/vm/hugetlbpage.txt | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff -puN Documentation/vm/hugetlbpage.txt~mm-doc-cleanup-and-clarify-munmap-behavior-for-hugetlb-memory-fix Documentation/vm/hugetlbpage.txt
--- a/Documentation/vm/hugetlbpage.txt~mm-doc-cleanup-and-clarify-munmap-behavior-for-hugetlb-memory-fix
+++ a/Documentation/vm/hugetlbpage.txt
@@ -313,8 +313,11 @@ into /proc/sys/vm/hugetlb_shm_group. It
applications to use any combination of mmaps and shm* calls, though the mount of
filesystem will be required for using mmap calls without MAP_HUGETLB.
-When using munmap(2) to unmap hugetlb memory, the length specified must be
-hugepage aligned, otherwise it will fail with errno set to EINVAL.
+Syscalls that operate on memory backed by hugetlb pages only have their lengths
+aligned to the native page size of the processor; they will normally fail with
+errno set to EINVAL or exclude hugetlb pages that extend beyond the length if
+not hugepage aligned. For example, munmap(2) will fail if memory is backed by
+a hugetlb page and the length is smaller than the hugepage size.
Examples
_
Patches currently in -mm which might be from rientjes@xxxxxxxxxx are
mm-move-zone-lock-to-a-different-cache-line-than-order-0-free-page-lists.patch
mm-numa-disable-change-protection-for-vmavm_hugetlb.patch
cxgb4-drop-__gfp_nofail-allocation.patch
sh-dwarf-destroy-mempools-on-cleanup.patch
sh-dwarf-use-mempool_create_slab_pool.patch
jbd2-revert-must-not-fail-allocation-loops-back-to-gfp_nofail.patch
mm-slub-parse-slub_debug-o-option-in-switch-statement.patch
mm-slab-correct-config-option-in-comment.patch
slub-use-bool-function-return-values-of-true-false-not-1-0.patch
mm-rename-foll_mlock-to-foll_populate.patch
mm-rename-__mlock_vma_pages_range-to-populate_vma_page_range.patch
mm-move-gup-posix-mlock-error-conversion-out-of-__mm_populate.patch
mm-move-mm_populate-related-code-to-mm-gupc.patch
mm-hotplug-fix-concurrent-memory-hot-add-deadlock.patch
mm-cma-change-fallback-behaviour-for-cma-freepage.patch
mm-page_alloc-factor-out-fallback-freepage-checking.patch
mm-compaction-enhance-compaction-finish-condition.patch
mm-compaction-enhance-compaction-finish-condition-fix.patch
mm-incorporate-zero-pages-into-transparent-huge-pages.patch
mm-incorporate-zero-pages-into-transparent-huge-pages-fix.patch
mm-completely-remove-dumping-per-cpu-lists-from-show_mem.patch
mm-mempolicy-migrate_to_node-should-only-migrate-to-node.patch
mm-remove-gfp_thisnode.patch
mm-thp-really-limit-transparent-hugepage-allocation-to-local-node.patch
kernel-cpuset-remove-exception-for-__gfp_thisnode.patch
mm-clarify-__gfp_nofail-deprecation-status.patch
mm-clarify-__gfp_nofail-deprecation-status-checkpatch-fixes.patch
sparc-clarify-__gfp_nofail-allocation.patch
mm-mempool-do-not-allow-atomic-resizing.patch
mm-mempool-do-not-allow-atomic-resizing-checkpatch-fixes.patch
mm-hugetlb-abort-__get_user_pages-if-current-has-been-oom-killed.patch
mm-refactor-zone_movable_is_highmem.patch
mm-memory-failurec-define-page-types-for-action_result-in-one-place.patch
page-flags-define-behavior-slb-related-flags-on-compound-pages.patch
allow-compaction-of-unevictable-pages.patch
document-interaction-between-compaction-and-the-unevictable-lru.patch
document-interaction-between-compaction-and-the-unevictable-lru-fix.patch
mm-compaction-reset-compaction-scanner-positions.patch
hugetlbfs-add-minimum-size-tracking-fields-to-subpool-structure.patch
hugetlbfs-add-minimum-size-accounting-to-subpools.patch
hugetlbfs-accept-subpool-min_size-mount-option-and-setup-accordingly.patch
hugetlbfs-document-min_size-mount-option-and-cleanup.patch
mm-vmalloc-fix-possible-exhaustion-of-vmalloc-space-caused-by-vm_map_ram-allocator.patch
mm-vmalloc-occupy-newly-allocated-vmap-block-just-after-allocation.patch
mm-vmalloc-get-rid-of-dirty-bitmap-inside-vmap_block-structure.patch
mremap-should-return-enomem-when-__vm_enough_memory-fail.patch
clean-up-goto-just-return-err_ptr.patch
fs-jfs-remove-slab-object-constructor.patch
mm-mempool-disallow-mempools-based-on-slab-caches-with-constructors.patch
mm-mempool-poison-elements-backed-by-slab-allocator.patch
mm-mempool-poison-elements-backed-by-page-allocator.patch
mm-mempool-poison-elements-backed-by-page-allocator-fix.patch
thp-handle-errors-in-hugepage_init-properly.patch
thp-do-not-adjust-zone-water-marks-if-khugepaged-is-not-started.patch
mm-doc-cleanup-and-clarify-munmap-behavior-for-hugetlb-memory.patch
mm-doc-cleanup-and-clarify-munmap-behavior-for-hugetlb-memory-fix.patch
mm-selftests-test-return-value-of-munmap-for-map_hugetlb-memory.patch
mm-dont-call-__page_cache_release-for-hugetlb.patch
mm-hugetlb-introduce-pagehugeactive-flag.patch
mm-hugetlb-introduce-pagehugeactive-flag-fix.patch
mm-hugetlb-cleanup-using-pagehugeactive-flag.patch
mm-hugetlb-cleanup-using-pagehugeactive-flag-fix.patch
thp-cleanup-khugepaged-startup.patch
hung_task-change-hung_taskc-to-use-for_each_process_thread.patch
mm-utilc-add-kstrimdup.patch
linux-next.patch
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