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authorJoonsoo Kim <iamjoonsoo.kim@lge.com>2016-05-19 17:10:49 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2016-05-19 19:12:14 -0700
commit0139aa7b7fa12ceef095d99dc36606a5b10ab83a (patch)
tree94da74f2f79911a11a3c7c34f73ba971dec41a7e /mm/huge_memory.c
parentmm/page_ref: use page_ref helper instead of direct modification of _count (diff)
downloadlinux-dev-0139aa7b7fa12ceef095d99dc36606a5b10ab83a.tar.xz
linux-dev-0139aa7b7fa12ceef095d99dc36606a5b10ab83a.zip
mm: rename _count, field of the struct page, to _refcount
Many developers already know that field for reference count of the struct page is _count and atomic type. They would try to handle it directly and this could break the purpose of page reference count tracepoint. To prevent direct _count modification, this patch rename it to _refcount and add warning message on the code. After that, developer who need to handle reference count will find that field should not be accessed directly. [akpm@linux-foundation.org: fix comments, per Vlastimil] [akpm@linux-foundation.org: Documentation/vm/transhuge.txt too] [sfr@canb.auug.org.au: sync ethernet driver changes] Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Berg <johannes@sipsolutions.net> Cc: "David S. Miller" <davem@davemloft.net> Cc: Sunil Goutham <sgoutham@cavium.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Manish Chopra <manish.chopra@qlogic.com> Cc: Yuval Mintz <yuval.mintz@qlogic.com> Cc: Tariq Toukan <tariqt@mellanox.com> Cc: Saeed Mahameed <saeedm@mellanox.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/huge_memory.c')
-rw-r--r--mm/huge_memory.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index b49ee126d4d1..f8ac8f582fd8 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -3113,7 +3113,7 @@ static void __split_huge_page_tail(struct page *head, int tail,
VM_BUG_ON_PAGE(page_ref_count(page_tail) != 0, page_tail);
/*
- * tail_page->_count is zero and not changing from under us. But
+ * tail_page->_refcount is zero and not changing from under us. But
* get_page_unless_zero() may be running from under us on the
* tail_page. If we used atomic_set() below instead of atomic_inc(), we
* would then run atomic_set() concurrently with
@@ -3340,7 +3340,7 @@ int split_huge_page_to_list(struct page *page, struct list_head *list)
if (mlocked)
lru_add_drain();
- /* Prevent deferred_split_scan() touching ->_count */
+ /* Prevent deferred_split_scan() touching ->_refcount */
spin_lock_irqsave(&pgdata->split_queue_lock, flags);
count = page_count(head);
mapcount = total_mapcount(head);