linux-kernel - [PATCH v4 14/14] mm, debug: move bad flags printing to bad

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Date:	Tue, 26 Jan 2016 13:45:53 +0100
From:	Vlastimil Babka <vbabka@...e.cz>
To:	Andrew Morton <akpm@...ux-foundation.org>
Cc:	linux-kernel@...r.kernel.org, linux-mm@...ck.org,
	Vlastimil Babka <vbabka@...e.cz>,
	Joonsoo Kim <iamjoonsoo.kim@....com>,
	Minchan Kim <minchan@...nel.org>,
	Sasha Levin <sasha.levin@...cle.com>,
	"Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
	Mel Gorman <mgorman@...e.de>, Michal Hocko <mhocko@...e.com>
Subject: [PATCH v4 14/14] mm, debug: move bad flags printing to bad_page()

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@...e.cz>
Cc: Joonsoo Kim <iamjoonsoo.kim@....com>
Cc: Minchan Kim <minchan@...nel.org>
Cc: Sasha Levin <sasha.levin@...cle.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>
Cc: Mel Gorman <mgorman@...e.de>
Acked-by: Michal Hocko <mhocko@...e.com>
---
 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