The patch titled
Subject: mm/page_alloc.c: bad_flags is not necessary for bad_page()
has been added to the -mm tree. Its filename is
mm-page_allocc-bad_flags-is-not-necessary-for-bad_page.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-page_allocc-bad_flags-is-not-necessary-for-bad_page.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-page_allocc-bad_flags-is-not-necessary-for-bad_page.patch
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------------------------------------------------------
From: Wei Yang <richard.weiyang@xxxxxxxxx>
Subject: mm/page_alloc.c: bad_flags is not necessary for bad_page()
After commit 5b57b8f22709 ("mm/debug.c: always print flags in
dump_page()"), page->flags is always printed for a bad page. It is not
necessary to have bad_flags any more.
Link: http://lkml.kernel.org/r/20200411220357.9636-3-richard.weiyang@xxxxxxxxx
Signed-off-by: Wei Yang <richard.weiyang@xxxxxxxxx>
Suggested-by: Anshuman Khandual <anshuman.khandual@xxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/page_alloc.c | 34 ++++++++++------------------------
1 file changed, 10 insertions(+), 24 deletions(-)
--- a/mm/page_alloc.c~mm-page_allocc-bad_flags-is-not-necessary-for-bad_page
+++ a/mm/page_alloc.c
@@ -607,8 +607,7 @@ static inline int __maybe_unused bad_ran
}
#endif
-static void bad_page(struct page *page, const char *reason,
- unsigned long bad_flags)
+static void bad_page(struct page *page, const char *reason)
{
static unsigned long resume;
static unsigned long nr_shown;
@@ -637,10 +636,6 @@ static void bad_page(struct page *page,
pr_alert("BUG: Bad page state in process %s pfn:%05lx\n",
current->comm, page_to_pfn(page));
__dump_page(page, reason);
- bad_flags &= page->flags;
- if (bad_flags)
- pr_alert("bad because of flags: %#lx(%pGp)\n",
- bad_flags, &bad_flags);
dump_page_owner(page);
print_modules();
@@ -1077,11 +1072,7 @@ static inline bool page_expected_state(s
static void free_pages_check_bad(struct page *page)
{
- const char *bad_reason;
- unsigned long bad_flags;
-
- bad_reason = NULL;
- bad_flags = 0;
+ const char *bad_reason = NULL;
if (unlikely(atomic_read(&page->_mapcount) != -1))
bad_reason = "nonzero mapcount";
@@ -1089,15 +1080,13 @@ static void free_pages_check_bad(struct
bad_reason = "non-NULL mapping";
if (unlikely(page_ref_count(page) != 0))
bad_reason = "nonzero _refcount";
- if (unlikely(page->flags & PAGE_FLAGS_CHECK_AT_FREE)) {
+ 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;
- }
#ifdef CONFIG_MEMCG
if (unlikely(page->mem_cgroup))
bad_reason = "page still charged to cgroup";
#endif
- bad_page(page, bad_reason, bad_flags);
+ bad_page(page, bad_reason);
}
static inline int free_pages_check(struct page *page)
@@ -1128,7 +1117,7 @@ static int free_tail_pages_check(struct
case 1:
/* the first tail page: ->mapping may be compound_mapcount() */
if (unlikely(compound_mapcount(page))) {
- bad_page(page, "nonzero compound_mapcount", 0);
+ bad_page(page, "nonzero compound_mapcount");
goto out;
}
break;
@@ -1140,17 +1129,17 @@ static int free_tail_pages_check(struct
break;
default:
if (page->mapping != TAIL_MAPPING) {
- bad_page(page, "corrupted mapping in tail page", 0);
+ bad_page(page, "corrupted mapping in tail page");
goto out;
}
break;
}
if (unlikely(!PageTail(page))) {
- bad_page(page, "PageTail not set", 0);
+ bad_page(page, "PageTail not set");
goto out;
}
if (unlikely(compound_head(page) != head_page)) {
- bad_page(page, "compound_head not consistent", 0);
+ bad_page(page, "compound_head not consistent");
goto out;
}
ret = 0;
@@ -2094,7 +2083,6 @@ static inline void expand(struct zone *z
static void check_new_page_bad(struct page *page)
{
const char *bad_reason = NULL;
- unsigned long bad_flags = 0;
if (unlikely(page->flags & __PG_HWPOISON)) {
/* Don't complain about hwpoisoned pages */
@@ -2107,15 +2095,13 @@ static void check_new_page_bad(struct pa
bad_reason = "non-NULL mapping";
if (unlikely(page_ref_count(page) != 0))
bad_reason = "nonzero _refcount";
- if (unlikely(page->flags & PAGE_FLAGS_CHECK_AT_PREP)) {
+ 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
- bad_page(page, bad_reason, bad_flags);
+ bad_page(page, bad_reason);
}
/*
_
Patches currently in -mm which might be from richard.weiyang@xxxxxxxxx are
mm-page_allocc-bad_-is-not-necessary-when-pagehwpoison.patch
mm-page_allocc-bad_flags-is-not-necessary-for-bad_page.patch
mm-page_allocc-rename-free_pages_check_bad-to-check_free_page_bad.patch
mm-page_allocc-rename-free_pages_check-to-check_free_page.patch
mm-page_allocc-extract-check__page_bad-common-part-to-page_bad_reason.patch
