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authorLinus Torvalds <torvalds@linux-foundation.org>2019-11-06 12:02:13 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2019-11-06 12:02:13 -0800
commit4dd58158254c8a027f2bf5060b72ef64cafa3b9d (patch)
tree330fe82fb36a5a50815f156d90b1966e14418c6b /include
parent26bc672134241a080a83b2ab9aa8abede8d30e1c (diff)
parent869712fd3de5a90b7ba23ae1272278cddc66b37b (diff)
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')
-rw-r--r--include/linux/mm.h5
-rw-r--r--include/linux/mm_types.h5
-rw-r--r--include/linux/page-flags.h20
3 files changed, 23 insertions, 7 deletions
diff --git a/include/linux/mm.h b/include/linux/mm.h
index cc292273e6ba..a2adf95b3f9c 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -695,11 +695,6 @@ static inline void *kvcalloc(size_t n, size_t size, gfp_t flags)
extern void kvfree(const void *addr);
-static inline atomic_t *compound_mapcount_ptr(struct page *page)
-{
- return &page[1].compound_mapcount;
-}
-
static inline int compound_mapcount(struct page *page)
{
VM_BUG_ON_PAGE(!PageCompound(page), page);
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 2222fa795284..270aa8fd2800 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -221,6 +221,11 @@ struct page {
#endif
} _struct_page_alignment;
+static inline atomic_t *compound_mapcount_ptr(struct page *page)
+{
+ return &page[1].compound_mapcount;
+}
+
/*
* Used for sizing the vmemmap region on some architectures
*/
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));
}
/*