Thread (20 messages) 20 messages, 4 authors, 2012-09-03

Re: [PATCH 1/3] HWPOISON: fix action_result() to print out dirty/clean

From: Fengguang Wu <hidden>
Date: 2012-08-23 09:33:36
Also in: lkml

On Wed, Aug 22, 2012 at 11:17:33AM -0400, Naoya Horiguchi wrote:
quoted hunk ↗ jump to hunk
action_result() fails to print out "dirty" even if an error occurred on a
dirty pagecache, because when we check PageDirty in action_result() it was
cleared after page isolation even if it's dirty before error handling. This
can break some applications that monitor this message, so should be fixed.

There are several callers of action_result() except page_action(), but
either of them are not for LRU pages but for free pages or kernel pages,
so we don't have to consider dirty or not for them.

Signed-off-by: Naoya Horiguchi <redacted>
Reviewed-by: Andi Kleen <redacted>
---
 mm/memory-failure.c | 22 +++++++++-------------
 1 file changed, 9 insertions(+), 13 deletions(-)
diff --git v3.6-rc1.orig/mm/memory-failure.c v3.6-rc1/mm/memory-failure.c
index a6e2141..79dfb2f 100644
--- v3.6-rc1.orig/mm/memory-failure.c
+++ v3.6-rc1/mm/memory-failure.c
@@ -779,16 +779,16 @@ static struct page_state {
 	{ compound,	compound,	"huge",		me_huge_page },
 #endif
 
-	{ sc|dirty,	sc|dirty,	"swapcache",	me_swapcache_dirty },
-	{ sc|dirty,	sc,		"swapcache",	me_swapcache_clean },
+	{ sc|dirty,	sc|dirty,	"dirty swapcache",	me_swapcache_dirty },
+	{ sc|dirty,	sc,		"clean swapcache",	me_swapcache_clean },
 
-	{ unevict|dirty, unevict|dirty,	"unevictable LRU", me_pagecache_dirty},
-	{ unevict,	unevict,	"unevictable LRU", me_pagecache_clean},
+	{ unevict|dirty, unevict|dirty,	"dirty unevictable LRU", me_pagecache_dirty },
+	{ unevict,	unevict,	"clean unevictable LRU", me_pagecache_clean },
 
-	{ mlock|dirty,	mlock|dirty,	"mlocked LRU",	me_pagecache_dirty },
-	{ mlock,	mlock,		"mlocked LRU",	me_pagecache_clean },
+	{ mlock|dirty,	mlock|dirty,	"dirty mlocked LRU",	me_pagecache_dirty },
+	{ mlock,	mlock,		"clean mlocked LRU",	me_pagecache_clean },
 
-	{ lru|dirty,	lru|dirty,	"LRU",		me_pagecache_dirty },
+	{ lru|dirty,	lru|dirty,	"dirty LRU",	me_pagecache_dirty },
 	{ lru|dirty,	lru,		"clean LRU",	me_pagecache_clean },
According to the set_page_dirty() comment, the dirty bit might be set
outside the page lock (however I don't know any concrete examples).
That means the word "clean" is not 100% right.  That's probably why we
only report "dirty LRU" and didn't say "clean LRU".

Thanks,
Fengguang
quoted hunk ↗ jump to hunk
 	/*
@@ -812,12 +812,8 @@ static struct page_state {
 
 static void action_result(unsigned long pfn, char *msg, int result)
 {
-	struct page *page = pfn_to_page(pfn);
-
-	printk(KERN_ERR "MCE %#lx: %s%s page recovery: %s\n",
-		pfn,
-		PageDirty(page) ? "dirty " : "",
-		msg, action_name[result]);
+	pr_err("MCE %#lx: %s page recovery: %s\n",
+		pfn, msg, action_name[result]);
 }
 
 static int page_action(struct page_state *ps, struct page *p,
-- 
1.7.11.4
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