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From: Michal Hocko <mhocko@kernel.org>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Oscar Salvador <OSalvador@suse.com>, Baoquan He <bhe@redhat.com>,
	Anshuman Khandual <anshuman.khandual@arm.com>,
	<linux-mm@kvack.org>, LKML <linux-kernel@vger.kernel.org>,
	Michal Hocko <mhocko@suse.com>
Subject: [PATCH 1/5] mm: print more information about mapping in __dump_page
Date: Fri, 16 Nov 2018 09:30:16 +0100	[thread overview]
Message-ID: <20181116083020.20260-2-mhocko@kernel.org> (raw)
In-Reply-To: <20181116083020.20260-1-mhocko@kernel.org>

From: Michal Hocko <mhocko@suse.com>

__dump_page prints the mapping pointer but that is quite unhelpful
for many reports because the pointer itself only helps to distinguish
anon/ksm mappings from other ones (because of lowest bits
set). Sometimes it would be much more helpful to know what kind of
mapping that is actually and if we know this is a file mapping then also
try to resolve the dentry name.

Signed-off-by: Michal Hocko <mhocko@suse.com>
---
 mm/debug.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/mm/debug.c b/mm/debug.c
index cdacba12e09a..a33177bfc856 100644
--- a/mm/debug.c
+++ b/mm/debug.c
@@ -44,6 +44,7 @@ const struct trace_print_flags vmaflag_names[] = {
 
 void __dump_page(struct page *page, const char *reason)
 {
+	struct address_space *mapping = page_mapping(page);
 	bool page_poisoned = PagePoisoned(page);
 	int mapcount;
 
@@ -70,6 +71,18 @@ void __dump_page(struct page *page, const char *reason)
 	if (PageCompound(page))
 		pr_cont(" compound_mapcount: %d", compound_mapcount(page));
 	pr_cont("\n");
+	if (PageAnon(page))
+		pr_emerg("anon ");
+	else if (PageKsm(page))
+		pr_emerg("ksm ");
+	else if (mapping) {
+		pr_emerg("%ps ", mapping->a_ops);
+		if (mapping->host->i_dentry.first) {
+			struct dentry *dentry;
+			dentry = container_of(mapping->host->i_dentry.first, struct dentry, d_u.d_alias);
+			pr_emerg("name:\"%*s\" ", dentry->d_name.len, dentry->d_name.name);
+		}
+	}
 	BUILD_BUG_ON(ARRAY_SIZE(pageflag_names) != __NR_PAGEFLAGS + 1);
 
 	pr_emerg("flags: %#lx(%pGp)\n", page->flags, &page->flags);
-- 
2.19.1


  reply	other threads:[~2018-11-16  8:30 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-11-16  8:30 [PATCH 0/5] mm, memory_hotplug: improve memory offlining failures debugging Michal Hocko
2018-11-16  8:30 ` Michal Hocko [this message]
2018-11-16 11:55   ` [PATCH 1/5] mm: print more information about mapping in __dump_page Anshuman Khandual
2018-11-16 13:50   ` William Kucharski
2018-11-16  8:30 ` [PATCH 2/5] mm: lower the printk loglevel for __dump_page messages Michal Hocko
2018-11-16 11:57   ` Anshuman Khandual
2018-11-16  8:30 ` [PATCH 3/5] mm, memory_hotplug: drop pointless block alignment checks from __offline_pages Michal Hocko
2018-11-16 10:34   ` osalvador
2018-11-16 11:19     ` Michal Hocko
2018-11-16 11:56   ` Anshuman Khandual
2018-11-16  8:30 ` [PATCH 4/5] mm, memory_hotplug: print reason for the offlining failure Michal Hocko
2018-11-16 10:38   ` osalvador
2018-11-16 12:04   ` Anshuman Khandual
2018-11-16  8:30 ` [PATCH 5/5] mm, memory_hotplug: be more verbose for memory offline failures Michal Hocko
2018-11-16 10:47   ` osalvador
2018-11-16 11:22     ` Michal Hocko
2018-11-16 12:29       ` osalvador
2018-11-16 12:07   ` Anshuman Khandual
2018-11-16 11:55 ` [PATCH 0/5] mm, memory_hotplug: improve memory offlining failures debugging Anshuman Khandual

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