The patch titled
Subject: include/linux/hugetlb.h: add synchronization information for new hugetlb specific flags
has been added to the -mm tree. Its filename is
include-linux-hugetlbh-add-synchronization-information-for-new-hugetlb-specific-flags.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/include-linux-hugetlbh-add-synchronization-information-for-new-hugetlb-specific-flags.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/include-linux-hugetlbh-add-synchronization-information-for-new-hugetlb-specific-flags.patch
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------------------------------------------------------
From: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Subject: include/linux/hugetlb.h: add synchronization information for new hugetlb specific flags
Add comments, no functional change.
Link: https://lkml.kernel.org/r/62a80585-2a73-10cc-4a2d-5721540d4ad2@xxxxxxxxxx
Signed-off-by: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Acked-by: Michal Hocko <mhocko@xxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/hugetlb.h | 10 ++++++++++
1 file changed, 10 insertions(+)
--- a/include/linux/hugetlb.h~include-linux-hugetlbh-add-synchronization-information-for-new-hugetlb-specific-flags
+++ a/include/linux/hugetlb.h
@@ -480,14 +480,24 @@ unsigned long hugetlb_get_unmapped_area(
* HPG_restore_reserve - Set when a hugetlb page consumes a reservation at
* allocation time. Cleared when page is fully instantiated. Free
* routine checks flag to restore a reservation on error paths.
+ * Synchronization: Examined or modified by code that knows it has
+ * the only reference to page. i.e. After allocation but before use
+ * or when the page is being freed.
* HPG_migratable - Set after a newly allocated page is added to the page
* cache and/or page tables. Indicates the page is a candidate for
* migration.
+ * Synchronization: Initially set after new page allocation with no
+ * locking. When examined and modified during migration processing
+ * (isolate, migrate, putback) the hugetlb_lock is held.
* HPG_temporary - - Set on a page that is temporarily allocated from the buddy
* allocator. Typically used for migration target pages when no pages
* are available in the pool. The hugetlb free page path will
* immediately free pages with this flag set to the buddy allocator.
+ * Synchronization: Can be set after huge page allocation from buddy when
+ * code knows it has only reference. All other examinations and
+ * modifications require hugetlb_lock.
* HPG_freed - Set when page is on the free lists.
+ * Synchronization: hugetlb_lock held for examination and modification.
*/
enum hugetlb_page_flags {
HPG_restore_reserve = 0,
_
Patches currently in -mm which might be from mike.kravetz@xxxxxxxxxx are
hugetlb-fix-update_and_free_page-contig-page-struct-assumption.patch
hugetlb-fix-copy_huge_page_from_user-contig-page-struct-assumption.patch
hugetlb-use-pageprivate-for-hugetlb-specific-page-flags.patch
hugetlb-use-pageprivate-for-hugetlb-specific-page-flags-fix.patch
hugetlb-convert-page_huge_active-hpagemigratable-flag.patch
hugetlb-convert-pagehugetemporary-to-hpagetemporary-flag.patch
hugetlb-convert-pagehugefreed-to-hpagefreed-flag.patch
include-linux-hugetlbh-add-synchronization-information-for-new-hugetlb-specific-flags.patch
mm-hugetlb-change-hugetlb_reserve_pages-to-type-bool.patch
hugetlbfs-remove-special-hugetlbfs_set_page_dirty.patch
