linux-kernel - [PATCH] mm: memory_hotplug: put migration failure information under DEBUG

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Date:   Mon, 23 Nov 2020 19:33:16 +0530
From:   Charan Teja Reddy <charante@...eaurora.org>
To:     akpm@...ux-foundation.org, david@...hat.com, mhocko@...e.com,
        linux-mm@...ck.org
Cc:     linux-kernel@...r.kernel.org,
        Charan Teja Reddy <charante@...eaurora.org>
Subject: [PATCH] mm: memory_hotplug: put migration failure information under DEBUG_VM

When the pages are failed to get isolate or migrate, the page owner
information along with page info is dumped. If there are continuous
failures in migration(say page is pinned) or isolation, the log buffer
is simply getting flooded with the page owner information. As most of
the times page info is sufficient to know the causes for failures of
migration or isolation, place the page owner information under DEBUG_VM.

Signed-off-by: Charan Teja Reddy <charante@...eaurora.org>
---
 mm/memory_hotplug.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 63b2e46..f48f30d 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1326,7 +1326,10 @@ do_migrate_range(unsigned long start_pfn, unsigned long end_pfn)
 
 		} else {
 			pr_warn("failed to isolate pfn %lx\n", pfn);
-			dump_page(page, "isolation failed");
+			__dump_page(page, "isolation failed");
+#if defined(CONFIG_DEBUG_VM)
+			dump_page_owner(page);
+#endif
 		}
 		put_page(page);
 	}
@@ -1357,7 +1360,10 @@ do_migrate_range(unsigned long start_pfn, unsigned long end_pfn)
 			list_for_each_entry(page, &source, lru) {
 				pr_warn("migrating pfn %lx failed ret:%d ",
 				       page_to_pfn(page), ret);
-				dump_page(page, "migration failure");
+				__dump_page(page, "migration failure");
+#if defined(CONFIG_DEBUG_VM)
+				dump_page_owner(page);
+#endif
 			}
 			putback_movable_pages(&source);
 		}
-- 
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