Messages in this thread Patch in this message | | | From | Andi Kleen <> | Subject | [PATCH] [9/11] SYSCTL: Add a mutex to the page_alloc zone order sysctl | Date | Mon, 21 Dec 2009 02:20:30 +0100 (CET) |
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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: Andi Kleen <ak@linux.intel.com>
--- mm/page_alloc.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-)
Index: linux-2.6.33-rc1-ak/mm/page_alloc.c =================================================================== --- linux-2.6.33-rc1-ak.orig/mm/page_alloc.c +++ linux-2.6.33-rc1-ak/mm/page_alloc.c @@ -2401,13 +2401,14 @@ int numa_zonelist_order_handler(ctl_tabl { 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)) { @@ -2420,7 +2421,9 @@ int numa_zonelist_order_handler(ctl_tabl } else if (oldval != user_zonelist_order) build_all_zonelists(); } - return 0; +out: + mutex_unlock(&zl_order_mutex); + return ret; }
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