Commit ae32b129 authored May 02, 2007 by Konrad Rzeszutek Committed by Andi Kleen May 02, 2007

[PATCH] x86-64: Inhibit machine from asserting an NMI when doing Alt-SysRq-M operation.



This patch touches the NMI watchdog every MAX_ORDER_NR_PAGES
to inhibit the machine from triggering an NMI while the CPUs
are locked. This situation is happening on boxes with more
than 64CPUs and 128GB of RAM when Alt-SysRq-m is performed.

It has been succesfully tested for regression on uni, 2, 4, 8
32, and 64 CPU boxes with various memory configuration.

Signed-off-by: Andi Kleen <ak@suse.de>

parent c8118c6c

arch/x86_64/mm/init.c

+6 −0

Original line number	Diff line number	Diff line
		@@ -27,6 +27,7 @@
		#include <linux/dma-mapping.h>
		#include <linux/module.h>
		#include <linux/memory_hotplug.h>
		#include <linux/nmi.h>

		#include <asm/processor.h>
		#include <asm/system.h>
		@@ -73,6 +74,11 @@ void show_mem(void)

		for_each_online_pgdat(pgdat) {
		for (i = 0; i < pgdat->node_spanned_pages; ++i) {
		/* this loop can take a while with 256 GB and 4k pages
		so update the NMI watchdog */
		if (unlikely(i % MAX_ORDER_NR_PAGES == 0)) {
		touch_nmi_watchdog();
		}
		page = pfn_to_page(pgdat->node_start_pfn + i);
		total++;
		if (PageReserved(page))