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| author | Peter Zijlstra <peterz@infradead.org> | 2016-05-30 18:31:33 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2016-06-08 14:22:00 +0200 |
| commit | dfaaf3fa01d65cf6e2072965bb0b7aaa7285344f (patch) | |
| tree | e2b993df8b9fd932668875f3f985beadecd12f9e /kernel/locking/lockdep.c | |
| parent | ed8ebd1d514126c0e54fbdbd231427dc91c877c2 (diff) | |
| download | lwn-dfaaf3fa01d65cf6e2072965bb0b7aaa7285344f.tar.gz lwn-dfaaf3fa01d65cf6e2072965bb0b7aaa7285344f.zip | |
locking/lockdep: Use __jhash_mix() for iterate_chain_key()
Use __jhash_mix() to mix the class_idx into the class_key. This
function provides better mixing than the previously used, home grown
mix function.
Leave hashing to the professionals :-)
Suggested-by: George Spelvin <linux@sciencehorizons.net>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/locking/lockdep.c')
| -rw-r--r-- | kernel/locking/lockdep.c | 13 |
1 files changed, 9 insertions, 4 deletions
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c index 81f1a7107c0e..589d763a49b3 100644 --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -46,6 +46,7 @@ #include <linux/gfp.h> #include <linux/kmemcheck.h> #include <linux/random.h> +#include <linux/jhash.h> #include <asm/sections.h> @@ -309,10 +310,14 @@ static struct hlist_head chainhash_table[CHAINHASH_SIZE]; * It's a 64-bit hash, because it's important for the keys to be * unique. */ -#define iterate_chain_key(key1, key2) \ - (((key1) << MAX_LOCKDEP_KEYS_BITS) ^ \ - ((key1) >> (64-MAX_LOCKDEP_KEYS_BITS)) ^ \ - (key2)) +static inline u64 iterate_chain_key(u64 key, u32 idx) +{ + u32 k0 = key, k1 = key >> 32; + + __jhash_mix(idx, k0, k1); /* Macro that modifies arguments! */ + + return k0 | (u64)k1 << 32; +} void lockdep_off(void) { |