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Commit 443c6f14 authored by Andi Kleen's avatar Andi Kleen
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SYSCTL: Add a mutex to the page_alloc zone order sysctl 



The zone list code clearly cannot tolerate concurrent writers (I couldn't
find any locks for that), so simply add a global mutex. No need for RCU
in this case.

Signed-off-by: default avatarAndi Kleen <ak@linux.intel.com>
parent 4440095c

mm/page_alloc.c

+7 −4
Original line number Diff line number Diff line
@@ -2402,13 +2402,14 @@ int numa_zonelist_order_handler(ctl_table *table, int write, 
{

	char saved_string[NUMA_ZONELIST_ORDER_LEN];

	int ret;

	static DEFINE_MUTEX(zl_order_mutex);



	mutex_lock(&zl_order_mutex);

	if (write)

		strncpy(saved_string, (char*)table->data,

			NUMA_ZONELIST_ORDER_LEN);

		strcpy(saved_string, (char*)table->data);

	ret = proc_dostring(table, write, buffer, length, ppos);

	if (ret)

		return ret;

		goto out;

	if (write) {

		int oldval = user_zonelist_order;

		if (__parse_numa_zonelist_order((char*)table->data)) {
@@ -2421,7 +2422,9 @@ int numa_zonelist_order_handler(ctl_table *table, int write, 
		} else if (oldval != user_zonelist_order)

			build_all_zonelists();

	}

	return 0;

out:

	mutex_unlock(&zl_order_mutex);

	return ret;

}