futexes: Fix futex_hashsize initialization
"futexes: Increase hash table size for better performance"
introduces a new alloc_large_system_hash() call.
alloc_large_system_hash() however may allocate less memory than
requested, e.g. limited by MAX_ORDER.
Hence pass a pointer to alloc_large_system_hash() which will
contain the hash shift when the function returns. Afterwards
correctly set futex_hashsize.
Fixes a crash on s390 where the requested allocation size was
4MB but only 1MB was allocated.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Darren Hart <dvhart@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Waiman Long <Waiman.Long@hp.com>
Cc: Jason Low <jason.low2@hp.com>
Cc: Davidlohr Bueso <davidlohr@hp.com>
Link: http://lkml.kernel.org/r/20140116135450.GA4345@osiris
Signed-off-by: Ingo Molnar <mingo@kernel.org>
diff --git a/kernel/futex.c b/kernel/futex.c
index 30971b5..1ddc449 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -2844,6 +2844,7 @@
static int __init futex_init(void)
{
u32 curval;
+ unsigned int futex_shift;
unsigned long i;
#if CONFIG_BASE_SMALL
@@ -2855,8 +2856,9 @@
futex_queues = alloc_large_system_hash("futex", sizeof(*futex_queues),
futex_hashsize, 0,
futex_hashsize < 256 ? HASH_SMALL : 0,
- NULL, NULL, futex_hashsize, futex_hashsize);
-
+ &futex_shift, NULL,
+ futex_hashsize, futex_hashsize);
+ futex_hashsize = 1UL << futex_shift;
/*
* This will fail and we want it. Some arch implementations do
* runtime detection of the futex_atomic_cmpxchg_inatomic()