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author | Linus Torvalds <torvalds@linux-foundation.org> | 2019-11-06 23:02:13 +0300 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2019-11-06 23:02:13 +0300 |
commit | 4dd58158254c8a027f2bf5060b72ef64cafa3b9d (patch) | |
tree | 330fe82fb36a5a50815f156d90b1966e14418c6b /include/linux/page-flags.h | |
parent | 26bc672134241a080a83b2ab9aa8abede8d30e1c (diff) | |
parent | 869712fd3de5a90b7ba23ae1272278cddc66b37b (diff) | |
download | linux-4dd58158254c8a027f2bf5060b72ef64cafa3b9d.tar.xz |
Merge branch 'akpm' (patches from Andrew)
Merge more fixes from Andrew Morton:
"17 fixes"
Mostly mm fixes and one ocfs2 locking fix.
* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
mm: memcontrol: fix network errors from failing __GFP_ATOMIC charges
mm/memory_hotplug: fix updating the node span
scripts/gdb: fix debugging modules compiled with hot/cold partitioning
mm: slab: make page_cgroup_ino() to recognize non-compound slab pages properly
MAINTAINERS: update information for "MEMORY MANAGEMENT"
dump_stack: avoid the livelock of the dump_lock
zswap: add Vitaly to the maintainers list
mm/page_alloc.c: ratelimit allocation failure warnings more aggressively
mm/khugepaged: fix might_sleep() warn with CONFIG_HIGHPTE=y
mm, vmstat: reduce zone->lock holding time by /proc/pagetypeinfo
mm, vmstat: hide /proc/pagetypeinfo from normal users
mm/mmu_notifiers: use the right return code for WARN_ON
ocfs2: protect extent tree in ocfs2_prepare_inode_for_write()
mm: thp: handle page cache THP correctly in PageTransCompoundMap
mm, meminit: recalculate pcpu batch and high limits after init completes
mm/gup_benchmark: fix MAP_HUGETLB case
mm: memcontrol: fix NULL-ptr deref in percpu stats flush
Diffstat (limited to 'include/linux/page-flags.h')
-rw-r--r-- | include/linux/page-flags.h | 20 |
1 files changed, 18 insertions, 2 deletions
diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h index f91cb8898ff0..1bf83c8fcaa7 100644 --- a/include/linux/page-flags.h +++ b/include/linux/page-flags.h @@ -622,12 +622,28 @@ static inline int PageTransCompound(struct page *page) * * Unlike PageTransCompound, this is safe to be called only while * split_huge_pmd() cannot run from under us, like if protected by the - * MMU notifier, otherwise it may result in page->_mapcount < 0 false + * MMU notifier, otherwise it may result in page->_mapcount check false * positives. + * + * We have to treat page cache THP differently since every subpage of it + * would get _mapcount inc'ed once it is PMD mapped. But, it may be PTE + * mapped in the current process so comparing subpage's _mapcount to + * compound_mapcount to filter out PTE mapped case. */ static inline int PageTransCompoundMap(struct page *page) { - return PageTransCompound(page) && atomic_read(&page->_mapcount) < 0; + struct page *head; + + if (!PageTransCompound(page)) + return 0; + + if (PageAnon(page)) + return atomic_read(&page->_mapcount) < 0; + + head = compound_head(page); + /* File THP is PMD mapped and not PTE mapped */ + return atomic_read(&page->_mapcount) == + atomic_read(compound_mapcount_ptr(head)); } /* |