linux-hardened/lib/show_mem.c
David Rientjes ddd588b5dd oom: suppress nodes that are not allowed from meminfo on oom kill
The oom killer is extremely verbose for machines with a large number of
cpus and/or nodes.  This verbosity can often be harmful if it causes other
important messages to be scrolled from the kernel log and incurs a
signicant time delay, specifically for kernels with CONFIG_NODES_SHIFT >
8.

This patch causes only memory information to be displayed for nodes that
are allowed by current's cpuset when dumping the VM state.  Information
for all other nodes is irrelevant to the oom condition; we don't care if
there's an abundance of memory elsewhere if we can't access it.

This only affects the behavior of dumping memory information when an oom
is triggered.  Other dumps, such as for sysrq+m, still display the
unfiltered form when using the existing show_mem() interface.

Additionally, the per-cpu pageset statistics are extremely verbose in oom
killer output, so it is now suppressed.  This removes

	nodes_weight(current->mems_allowed) * (1 + nr_cpus)

lines from the oom killer output.

Callers may use __show_mem(SHOW_MEM_FILTER_NODES) to filter disallowed
nodes.

Signed-off-by: David Rientjes <rientjes@google.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-22 17:44:01 -07:00

68 lines
1.4 KiB
C

/*
* Generic show_mem() implementation
*
* Copyright (C) 2008 Johannes Weiner <hannes@saeurebad.de>
* All code subject to the GPL version 2.
*/
#include <linux/mm.h>
#include <linux/nmi.h>
#include <linux/quicklist.h>
void __show_mem(unsigned int filter)
{
pg_data_t *pgdat;
unsigned long total = 0, reserved = 0, shared = 0,
nonshared = 0, highmem = 0;
printk("Mem-Info:\n");
__show_free_areas(filter);
for_each_online_pgdat(pgdat) {
unsigned long i, flags;
pgdat_resize_lock(pgdat, &flags);
for (i = 0; i < pgdat->node_spanned_pages; i++) {
struct page *page;
unsigned long pfn = pgdat->node_start_pfn + i;
if (unlikely(!(i % MAX_ORDER_NR_PAGES)))
touch_nmi_watchdog();
if (!pfn_valid(pfn))
continue;
page = pfn_to_page(pfn);
if (PageHighMem(page))
highmem++;
if (PageReserved(page))
reserved++;
else if (page_count(page) == 1)
nonshared++;
else if (page_count(page) > 1)
shared += page_count(page) - 1;
total++;
}
pgdat_resize_unlock(pgdat, &flags);
}
printk("%lu pages RAM\n", total);
#ifdef CONFIG_HIGHMEM
printk("%lu pages HighMem\n", highmem);
#endif
printk("%lu pages reserved\n", reserved);
printk("%lu pages shared\n", shared);
printk("%lu pages non-shared\n", nonshared);
#ifdef CONFIG_QUICKLIST
printk("%lu pages in pagetable cache\n",
quicklist_total_size());
#endif
}
void show_mem(void)
{
__show_mem(0);
}