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Date: Tue, 25 Aug 2015 21:26:30 +0800
From: Yaowei Bai <bywxiaobai@....com>
To: akpm@...ux-foundation.org, mgorman@...e.de, vbabka@...e.cz,
mhocko@...nel.org, js1304@...il.com, hannes@...xchg.org,
alexander.h.duyck@...hat.com, sasha.levin@...cle.com
Cc: linux-mm@...ck.org, linux-kernel@...r.kernel.org
Subject: [PATCH v2] mm/page_alloc: add a helper function to check page before alloc/free
The major portion of check_new_page() and free_pages_check() are same,
introduce a helper function check_one_page() for simplification.
Change in v2:
- use bad_flags as parameter directly per Michal Hocko
Signed-off-by: Yaowei Bai <bywxiaobai@....com>
---
mm/page_alloc.c | 49 ++++++++++++++++++-------------------------------
1 file changed, 18 insertions(+), 31 deletions(-)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 5b5240b..0a0acdb 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -707,10 +707,9 @@ out:
zone->free_area[order].nr_free++;
}
-static inline int free_pages_check(struct page *page)
+static inline int check_one_page(struct page *page, unsigned long bad_flags)
{
const char *bad_reason = NULL;
- unsigned long bad_flags = 0;
if (unlikely(page_mapcount(page)))
bad_reason = "nonzero mapcount";
@@ -718,9 +717,11 @@ static inline int free_pages_check(struct page *page)
bad_reason = "non-NULL mapping";
if (unlikely(atomic_read(&page->_count) != 0))
bad_reason = "nonzero _count";
- if (unlikely(page->flags & PAGE_FLAGS_CHECK_AT_FREE)) {
- bad_reason = "PAGE_FLAGS_CHECK_AT_FREE flag(s) set";
- bad_flags = PAGE_FLAGS_CHECK_AT_FREE;
+ if (unlikely(page->flags & bad_flags)) {
+ if (bad_flags == PAGE_FLAGS_CHECK_AT_PREP)
+ bad_reason = "PAGE_FLAGS_CHECK_AT_PREP flag set";
+ else if (bad_flags == PAGE_FLAGS_CHECK_AT_FREE)
+ bad_reason = "PAGE_FLAGS_CHECK_AT_FREE flag set";
}
#ifdef CONFIG_MEMCG
if (unlikely(page->mem_cgroup))
@@ -730,6 +731,17 @@ static inline int free_pages_check(struct page *page)
bad_page(page, bad_reason, bad_flags);
return 1;
}
+ return 0;
+}
+
+static inline int free_pages_check(struct page *page)
+{
+ int ret = 0;
+
+ ret = check_one_page(page, PAGE_FLAGS_CHECK_AT_FREE);
+ if (ret)
+ return ret;
+
page_cpupid_reset_last(page);
if (page->flags & PAGE_FLAGS_CHECK_AT_PREP)
page->flags &= ~PAGE_FLAGS_CHECK_AT_PREP;
@@ -1287,32 +1299,7 @@ static inline void expand(struct zone *zone, struct page *page,
*/
static inline int check_new_page(struct page *page)
{
- const char *bad_reason = NULL;
- unsigned long bad_flags = 0;
-
- if (unlikely(page_mapcount(page)))
- bad_reason = "nonzero mapcount";
- if (unlikely(page->mapping != NULL))
- bad_reason = "non-NULL mapping";
- if (unlikely(atomic_read(&page->_count) != 0))
- bad_reason = "nonzero _count";
- if (unlikely(page->flags & __PG_HWPOISON)) {
- bad_reason = "HWPoisoned (hardware-corrupted)";
- bad_flags = __PG_HWPOISON;
- }
- if (unlikely(page->flags & PAGE_FLAGS_CHECK_AT_PREP)) {
- bad_reason = "PAGE_FLAGS_CHECK_AT_PREP flag set";
- bad_flags = PAGE_FLAGS_CHECK_AT_PREP;
- }
-#ifdef CONFIG_MEMCG
- if (unlikely(page->mem_cgroup))
- bad_reason = "page still charged to cgroup";
-#endif
- if (unlikely(bad_reason)) {
- bad_page(page, bad_reason, bad_flags);
- return 1;
- }
- return 0;
+ return check_one_page(page, PAGE_FLAGS_CHECK_AT_PREP);
}
static int prep_new_page(struct page *page, unsigned int order, gfp_t gfp_flags,
--
1.9.1
--
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