From 0139aa7b7fa12ceef095d99dc36606a5b10ab83a Mon Sep 17 00:00:00 2001 From: Joonsoo Kim Date: Thu, 19 May 2016 17:10:49 -0700 Subject: 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 Signed-off-by: Stephen Rothwell Cc: Vlastimil Babka Cc: Hugh Dickins Cc: Johannes Berg Cc: "David S. Miller" Cc: Sunil Goutham Cc: Chris Metcalf Cc: Manish Chopra Cc: Yuval Mintz Cc: Tariq Toukan Cc: Saeed Mahameed Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/vmscan.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'mm/vmscan.c') diff --git a/mm/vmscan.c b/mm/vmscan.c index 142cb61f4822..d3a02ac3eed7 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -633,7 +633,7 @@ static int __remove_mapping(struct address_space *mapping, struct page *page, * * Reversing the order of the tests ensures such a situation cannot * escape unnoticed. The smp_rmb is needed to ensure the page->flags - * load is not satisfied before that of page->_count. + * load is not satisfied before that of page->_refcount. * * Note that if SetPageDirty is always performed via set_page_dirty, * and thus under tree_lock, then this ordering is not required. @@ -1720,7 +1720,7 @@ shrink_inactive_list(unsigned long nr_to_scan, struct lruvec *lruvec, * It is safe to rely on PG_active against the non-LRU pages in here because * nobody will play with that bit on a non-LRU page. * - * The downside is that we have to touch page->_count against each page. + * The downside is that we have to touch page->_refcount against each page. * But we had to alter page->flags anyway. */ -- cgit v1.2.3