[PATCH v2 3/3] mm, debug: move bad flags printing to bad_page()

Vlastimil Babka
2015-12-04T15:17:10Z

Since bad_page() is the only user of the badflags parameter of
dump_page_badflags(), we can move the code to bad_page() and simplify a bit.

The dump_page_badflags() function is renamed to __dump_page() and can still be
called separately from dump_page() for temporary debug prints where page_owner
info is not desired.

The only user-visible change is that page->mem_cgroup is printed before the bad
flags.

Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@suse.cz>
---
include/linux/mmdebug.h | 3 +--
mm/debug.c | 14 +++-----------
mm/page_alloc.c | 10 +++++++---
3 files changed, 11 insertions(+), 16 deletions(-)

diff --git a/include/linux/mmdebug.h b/include/linux/mmdebug.h
index 2c8286cf162e..9b0dc2161f7a 100644
--- a/include/linux/mmdebug.h
+++ b/include/linux/mmdebug.h
@@ -14,8 +14,7 @@ extern const struct trace_print_flags vmaflag_names[];
extern const struct trace_print_flags gfpflag_names[];

extern void dump_page(struct page *page, const char *reason);
-extern void dump_page_badflags(struct page *page, const char *reason,
- unsigned long badflags);
+extern void __dump_page(struct page *page, const char *reason);
void dump_vma(const struct vm_area_struct *vma);
void dump_mm(const struct mm_struct *mm);

diff --git a/mm/debug.c b/mm/debug.c
index c42bb4c13c2d..d36aa66e9779 100644
--- a/mm/debug.c
+++ b/mm/debug.c
@@ -109,25 +109,17 @@ const struct trace_print_flags gfpflag_names[] = {
{0, NULL},
};

-void dump_page_badflags(struct page *page, const char *reason,
- unsigned long badflags)
+void __dump_page(struct page *page, const char *reason)
{
- unsigned long printflags = page->flags;
-
pr_emerg("page:%p count:%d mapcount:%d mapping:%p index:%#lx\n",
page, atomic_read(&page->_count), page_mapcount(page),
page->mapping, page->index);
BUILD_BUG_ON(ARRAY_SIZE(pageflag_names) != __NR_PAGEFLAGS + 1);

- pr_emerg("flags: %#lx(%pgp)\n", printflags, &printflags);
+ pr_emerg("flags: %#lx(%pgp)\n", page->flags, &page->flags);

if (reason)
pr_alert("page dumped because: %s\n", reason);
- if (page->flags & badflags) {
- printflags = page->flags & badflags;
- pr_alert("bad because of flags: %#lx(%pgp)\n", printflags,
- &printflags);
- }
#ifdef CONFIG_MEMCG
if (page->mem_cgroup)
pr_alert("page->mem_cgroup:%p\n", page->mem_cgroup);
@@ -136,7 +128,7 @@ void dump_page_badflags(struct page *page, const char *reason,

void dump_page(struct page *page, const char *reason)
{
- dump_page_badflags(page, reason, 0);
+ __dump_page(page, reason);
dump_page_owner(page);
}
EXPORT_SYMBOL(dump_page);
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index bd94c7465dea..2388496a7c6c 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -435,7 +435,7 @@ static void bad_page(struct page *page, const char *reason,
goto out;
}
if (nr_unshown) {
- printk(KERN_ALERT
+ pr_alert(
"BUG: Bad page state: %lu messages suppressed\n",
nr_unshown);
nr_unshown = 0;
@@ -445,9 +445,13 @@ static void bad_page(struct page *page, const char *reason,
if (nr_shown++ == 0)
resume = jiffies + 60 * HZ;

- printk(KERN_ALERT "BUG: Bad page state in process %s pfn:%05lx\n",
+ pr_alert("BUG: Bad page state in process %s pfn:%05lx\n",
current->comm, page_to_pfn(page));
- dump_page_badflags(page, reason, bad_flags);
+ __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();
--
2.6.3