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Commit 718a3821 authored by Wu Fengguang's avatar Wu Fengguang Committed by Linus Torvalds
Browse files

mm: introduce dump_page() and print symbolic flag names 



- introduce dump_page() to print the page info for debugging some error
  condition.

- convert three mm users: bad_page(), print_bad_pte() and memory offline
  failure.

- print an extra field: the symbolic names of page->flags

Example dump_page() output:

[  157.521694] page:ffffea0000a7cba8 count:2 mapcount:1 mapping:ffff88001c901791 index:0x147
[  157.525570] page flags: 0x100000000100068(uptodate|lru|active|swapbacked)

Signed-off-by: default avatarWu Fengguang <fengguang.wu@intel.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Alex Chiang <achiang@hp.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Mel Gorman <mel@linux.vnet.ibm.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 9b3a6549

include/linux/mm.h

+2 −0
Original line number Diff line number Diff line
@@ -1465,5 +1465,7 @@ extern void shake_page(struct page *p, int access); 
extern atomic_long_t mce_bad_pages;

extern int soft_offline_page(struct page *page, int flags);



extern void dump_page(struct page *page);



#endif /* __KERNEL__ */

#endif /* _LINUX_MM_H */

mm/memory.c

+2 −6
Original line number Diff line number Diff line
@@ -509,12 +509,8 @@ static void print_bad_pte(struct vm_area_struct *vma, unsigned long addr, 
		"BUG: Bad page map in process %s  pte:%08llx pmd:%08llx\n",

		current->comm,

		(long long)pte_val(pte), (long long)pmd_val(*pmd));

	if (page) {

		printk(KERN_ALERT

		"page:%p flags:%p count:%d mapcount:%d mapping:%p index:%lx\n",

		page, (void *)page->flags, page_count(page),

		page_mapcount(page), page->mapping, page->index);

	}

	if (page)

		dump_page(page);

	printk(KERN_ALERT

		"addr:%p vm_flags:%08lx anon_vma:%p mapping:%p index:%lx\n",

		(void *)addr, vma->vm_flags, vma->anon_vma, mapping, index);

mm/memory_hotplug.c

+3 −3
Original line number Diff line number Diff line
@@ -688,9 +688,9 @@ do_migrate_range(unsigned long start_pfn, unsigned long end_pfn) 
			if (page_count(page))

				not_managed++;

#ifdef CONFIG_DEBUG_VM

			printk(KERN_INFO "removing from LRU failed"

					 " %lx/%d/%lx\n",

				pfn, page_count(page), page->flags);

			printk(KERN_ALERT "removing pfn %lx from LRU failed\n",

			       pfn);

			dump_page(page);

#endif

		}

	}

mm/page_alloc.c

+79 −4
Original line number Diff line number Diff line
@@ -50,6 +50,7 @@ 
#include <linux/kmemleak.h>

#include <linux/memory.h>

#include <trace/events/kmem.h>

#include <linux/ftrace_event.h>



#include <asm/tlbflush.h>

#include <asm/div64.h>
@@ -288,10 +289,7 @@ static void bad_page(struct page *page) 


	printk(KERN_ALERT "BUG: Bad page state in process %s  pfn:%05lx\n",

		current->comm, page_to_pfn(page));

	printk(KERN_ALERT

		"page:%p flags:%p count:%d mapcount:%d mapping:%p index:%lx\n",

		page, (void *)page->flags, page_count(page),

		page_mapcount(page), page->mapping, page->index);

	dump_page(page);



	dump_stack();

out:
@@ -5183,3 +5181,80 @@ bool is_free_buddy_page(struct page *page) 
	return order < MAX_ORDER;

}

#endif



static struct trace_print_flags pageflag_names[] = {

	{1UL << PG_locked,		"locked"	},

	{1UL << PG_error,		"error"		},

	{1UL << PG_referenced,		"referenced"	},

	{1UL << PG_uptodate,		"uptodate"	},

	{1UL << PG_dirty,		"dirty"		},

	{1UL << PG_lru,			"lru"		},

	{1UL << PG_active,		"active"	},

	{1UL << PG_slab,		"slab"		},

	{1UL << PG_owner_priv_1,	"owner_priv_1"	},

	{1UL << PG_arch_1,		"arch_1"	},

	{1UL << PG_reserved,		"reserved"	},

	{1UL << PG_private,		"private"	},

	{1UL << PG_private_2,		"private_2"	},

	{1UL << PG_writeback,		"writeback"	},

#ifdef CONFIG_PAGEFLAGS_EXTENDED

	{1UL << PG_head,		"head"		},

	{1UL << PG_tail,		"tail"		},

#else

	{1UL << PG_compound,		"compound"	},

#endif

	{1UL << PG_swapcache,		"swapcache"	},

	{1UL << PG_mappedtodisk,	"mappedtodisk"	},

	{1UL << PG_reclaim,		"reclaim"	},

	{1UL << PG_buddy,		"buddy"		},

	{1UL << PG_swapbacked,		"swapbacked"	},

	{1UL << PG_unevictable,		"unevictable"	},

#ifdef CONFIG_MMU

	{1UL << PG_mlocked,		"mlocked"	},

#endif

#ifdef CONFIG_ARCH_USES_PG_UNCACHED

	{1UL << PG_uncached,		"uncached"	},

#endif

#ifdef CONFIG_MEMORY_FAILURE

	{1UL << PG_hwpoison,		"hwpoison"	},

#endif

	{-1UL,				NULL		},

};



static void dump_page_flags(unsigned long flags)

{

	const char *delim = "";

	unsigned long mask;

	int i;



	printk(KERN_ALERT "page flags: %#lx(", flags);



	/* remove zone id */

	flags &= (1UL << NR_PAGEFLAGS) - 1;



	for (i = 0; pageflag_names[i].name && flags; i++) {



		mask = pageflag_names[i].mask;

		if ((flags & mask) != mask)

			continue;



		flags &= ~mask;

		printk("%s%s", delim, pageflag_names[i].name);

		delim = "|";

	}



	/* check for left over flags */

	if (flags)

		printk("%s%#lx", delim, flags);



	printk(")\n");

}



void dump_page(struct page *page)

{

	printk(KERN_ALERT

	       "page:%p count:%d mapcount:%d mapping:%p index:%#lx\n",

		page, page_count(page), page_mapcount(page),

		page->mapping, page->index);

	dump_page_flags(page->flags);

}