Commit 4b59e6c4 authored by David Rientjes's avatar David Rientjes Committed by Linus Torvalds
Browse files

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: default avatarDavid Rientjes <rientjes@google.com>
Cc: Mel Gorman <mgorman@suse.de>
Acked-by: default avatarMichal Hocko <mhocko@suse.cz>
Cc: Dave Hansen <dave@linux.vnet.ibm.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus 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;

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