From: Matthew Wilcox (Oracle) <willy@infradead.org>
Date: Wed, 24 Feb 2021 20:01:29 +0000 (-0800)
Subject: mm/debug: improve memcg debugging
X-Git-Tag: v5.12-rc1-dontuse~40^2~148
X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=91f5345afbc6b58d79b5c5d0bc915fa83e9d238e;p=linux-2.6-block.git

mm/debug: improve memcg debugging

The memcg_data is only valid on the head page, not the tail pages.  Change
the format and location of the printout within the dump to match the other
parts of struct page better.

Link: https://lkml.kernel.org/r/20210114190200.1894484-1-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

diff --git a/mm/debug.c b/mm/debug.c
index 8a40b3fefbeb..0bdda8407f71 100644
--- a/mm/debug.c
+++ b/mm/debug.c
@@ -110,6 +110,11 @@ void __dump_page(struct page *page, const char *reason)
 					head_compound_mapcount(head));
 		}
 	}
+
+#ifdef CONFIG_MEMCG
+	if (head->memcg_data)
+		pr_warn("memcg:%lx\n", head->memcg_data);
+#endif
 	if (PageKsm(page))
 		type = "ksm ";
 	else if (PageAnon(page))
@@ -180,11 +185,6 @@ hex_only:
 
 	if (reason)
 		pr_warn("page dumped because: %s\n", reason);
-
-#ifdef CONFIG_MEMCG
-	if (!page_poisoned && page->memcg_data)
-		pr_warn("pages's memcg:%lx\n", page->memcg_data);
-#endif
 }
 
 void dump_page(struct page *page, const char *reason)