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Commit 4b59e6c4 authored Apr 29, 2013 by David Rientjes Committed by Linus Torvalds Apr 29, 2013

mm, show_mem: suppress page counts in non-blockable contexts



On large systems with a lot of memory, walking all RAM to determine page
types may take a half second or even more.

In non-blockable contexts, the page allocator will emit a page allocation
failure warning unless __GFP_NOWARN is specified.  In such contexts, irqs
are typically disabled and such a lengthy delay may even result in NMI
watchdog timeouts.

To fix this, suppress the page walk in such contexts when printing the
page allocation failure warning.

Signed-off-by: David Rientjes <rientjes@google.com>
Cc: Mel Gorman <mgorman@suse.de>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Dave Hansen <dave@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent fe0bfaaf

arch/arm/mm/init.c

+3 −0

Original line number	Diff line number	Diff line
		@@ -99,6 +99,9 @@ void show_mem(unsigned int filter)
		printk("Mem-info:\n");
		show_free_areas(filter);

		if (filter & SHOW_MEM_FILTER_PAGE_COUNT)
		return;

		for_each_bank (i, mi) {
		struct membank *bank = &mi->bank[i];
		unsigned int pfn1, pfn2;

arch/ia64/mm/contig.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -47,6 +47,8 @@ void show_mem(unsigned int filter)
		printk(KERN_INFO "Mem-info:\n");
		show_free_areas(filter);
		printk(KERN_INFO "Node memory in pages:\n");
		if (filter & SHOW_MEM_FILTER_PAGE_COUNT)
		return;
		for_each_online_pgdat(pgdat) {
		unsigned long present;
		unsigned long flags;

arch/ia64/mm/discontig.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -623,6 +623,8 @@ void show_mem(unsigned int filter)

		printk(KERN_INFO "Mem-info:\n");
		show_free_areas(filter);
		if (filter & SHOW_MEM_FILTER_PAGE_COUNT)
		return;
		printk(KERN_INFO "Node memory in pages:\n");
		for_each_online_pgdat(pgdat) {
		unsigned long present;

arch/parisc/mm/init.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -697,6 +697,8 @@ void show_mem(unsigned int filter)

		printk(KERN_INFO "Mem-info:\n");
		show_free_areas(filter);
		if (filter & SHOW_MEM_FILTER_PAGE_COUNT)
		return;
		#ifndef CONFIG_DISCONTIGMEM
		i = max_mapnr;
		while (i-- > 0) {

arch/unicore32/mm/init.c

+3 −0

Original line number	Diff line number	Diff line
		@@ -66,6 +66,9 @@ void show_mem(unsigned int filter)
		printk(KERN_DEFAULT "Mem-info:\n");
		show_free_areas(filter);

		if (filter & SHOW_MEM_FILTER_PAGE_COUNT)
		return;

		for_each_bank(i, mi) {
		struct membank *bank = &mi->bank[i];
		unsigned int pfn1, pfn2;