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authorHeiko Carstens <heiko.carstens@de.ibm.com>2014-01-16 14:54:50 +0100
committerIngo Molnar <mingo@kernel.org>2014-01-16 15:14:32 +0100
commit63b1a81699c2a45c9f737419b1ec1da0ecf92812 (patch)
tree10ff7584b7ccb999553e834f9f07b1bd8b84b5e2
parentf549ed1abc7e4f0292ce08c4143c64a610c8b2cb (diff)
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>
-rw-r--r--kernel/futex.c6
1 files changed, 4 insertions, 2 deletions
diff --git a/kernel/futex.c b/kernel/futex.c
index 30971b5c0e2d..1ddc4498f1e1 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -2844,6 +2844,7 @@ SYSCALL_DEFINE6(futex, u32 __user *, uaddr, int, op, u32, val,
static int __init futex_init(void)
{
u32 curval;
+ unsigned int futex_shift;
unsigned long i;
#if CONFIG_BASE_SMALL
@@ -2855,8 +2856,9 @@ static int __init futex_init(void)
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()