[PATCH v4 14/14] mm, debug: move bad flags printing to bad_page()

From: Vlastimil Babka
Date: Tue Jan 26 2016 - 07:47:54 EST


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@xxxxxxx>
Cc: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
Cc: Minchan Kim <minchan@xxxxxxxxxx>
Cc: Sasha Levin <sasha.levin@xxxxxxxxxx>
Cc: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxx>
Acked-by: Michal Hocko <mhocko@xxxxxxxx>
---
include/linux/mmdebug.h | 3 +--
mm/debug.c | 10 +++-------
mm/page_alloc.c | 10 +++++++---
3 files changed, 11 insertions(+), 12 deletions(-)

diff --git a/include/linux/mmdebug.h b/include/linux/mmdebug.h
index 93fff2971fd4..3fb9bc65d61d 100644
--- a/include/linux/mmdebug.h
+++ b/include/linux/mmdebug.h
@@ -15,8 +15,7 @@ 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 61b1f1bb328e..df7247b0b532 100644
--- a/mm/debug.c
+++ b/mm/debug.c
@@ -40,8 +40,7 @@ const struct trace_print_flags vmaflag_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)
{
pr_emerg("page:%p count:%d mapcount:%d mapping:%p index:%#lx",
page, atomic_read(&page->_count), page_mapcount(page),
@@ -50,15 +49,12 @@ void dump_page_badflags(struct page *page, const char *reason,
pr_cont(" compound_mapcount: %d", compound_mapcount(page));
pr_cont("\n");
BUILD_BUG_ON(ARRAY_SIZE(pageflag_names) != __NR_PAGEFLAGS + 1);
+
pr_emerg("flags: %#lx(%pGp)\n", page->flags, &page->flags);

if (reason)
pr_alert("page dumped because: %s\n", reason);

- badflags &= page->flags;
- if (badflags)
- pr_alert("bad because of flags: %#lx(%pGp)\n", badflags,
- &badflags);
#ifdef CONFIG_MEMCG
if (page->mem_cgroup)
pr_alert("page->mem_cgroup:%p\n", page->mem_cgroup);
@@ -67,7 +63,7 @@ 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 e8b3cb78b5cf..35f47f830b52 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -430,7 +430,7 @@ 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;
@@ -440,9 +440,13 @@ 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();
--
2.7.0