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-rw-r--r--kernel/futex.c26
1 files changed, 19 insertions, 7 deletions
diff --git a/kernel/futex.c b/kernel/futex.c
index 085f5fa0b342..577481d5c59d 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -63,6 +63,7 @@
#include <linux/sched/rt.h>
#include <linux/hugetlb.h>
#include <linux/freezer.h>
+#include <linux/bootmem.h>
#include <asm/futex.h>
@@ -70,8 +71,6 @@
int __read_mostly futex_cmpxchg_enabled;
-#define FUTEX_HASHBITS (CONFIG_BASE_SMALL ? 4 : 8)
-
/*
* Futex flags used to encode options to functions and preserve them across
* restarts.
@@ -149,9 +148,11 @@ static const struct futex_q futex_q_init = {
struct futex_hash_bucket {
spinlock_t lock;
struct plist_head chain;
-};
+} ____cacheline_aligned_in_smp;
-static struct futex_hash_bucket futex_queues[1<<FUTEX_HASHBITS];
+static unsigned long __read_mostly futex_hashsize;
+
+static struct futex_hash_bucket *futex_queues;
/*
* We hash on the keys returned from get_futex_key (see below).
@@ -161,7 +162,7 @@ static struct futex_hash_bucket *hash_futex(union futex_key *key)
u32 hash = jhash2((u32*)&key->both.word,
(sizeof(key->both.word)+sizeof(key->both.ptr))/4,
key->both.offset);
- return &futex_queues[hash & ((1 << FUTEX_HASHBITS)-1)];
+ return &futex_queues[hash & (futex_hashsize - 1)];
}
/*
@@ -2719,7 +2720,18 @@ SYSCALL_DEFINE6(futex, u32 __user *, uaddr, int, op, u32, val,
static int __init futex_init(void)
{
u32 curval;
- int i;
+ unsigned long i;
+
+#if CONFIG_BASE_SMALL
+ futex_hashsize = 16;
+#else
+ futex_hashsize = roundup_pow_of_two(256 * num_possible_cpus());
+#endif
+
+ 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);
/*
* This will fail and we want it. Some arch implementations do
@@ -2734,7 +2746,7 @@ static int __init futex_init(void)
if (cmpxchg_futex_value_locked(&curval, NULL, 0, 0) == -EFAULT)
futex_cmpxchg_enabled = 1;
- for (i = 0; i < ARRAY_SIZE(futex_queues); i++) {
+ for (i = 0; i < futex_hashsize; i++) {
plist_head_init(&futex_queues[i].chain);
spin_lock_init(&futex_queues[i].lock);
}