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| author | Tejun Heo <tj@kernel.org> | 2014-06-28 08:10:12 -0400 |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2014-06-28 08:10:12 -0400 |
| commit | d630dc4c9adb41e5bd1e06df2dbeaf622469ddd5 (patch) | |
| tree | 4dc8afb3469f6bb27f3737b48d398ea4fa10e3e6 | |
| parent | 55c6c814ae0aa896781d3c51e4608de542624f64 (diff) | |
| download | linux-d630dc4c9adb41e5bd1e06df2dbeaf622469ddd5.tar.gz linux-d630dc4c9adb41e5bd1e06df2dbeaf622469ddd5.tar.bz2 linux-d630dc4c9adb41e5bd1e06df2dbeaf622469ddd5.zip | |
percpu-refcount: one bit is enough for REF_STATUS
percpu-refcount currently reserves two lowest bits of its percpu
pointer to indicate its state; however, only one bit is used for
PCPU_REF_DEAD.
Simplify it by removing PCPU_STATUS_BITS/MASK and testing
PCPU_REF_DEAD directly. This also allows the compiler to choose a
more efficient instruction depending on the architecture.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Kent Overstreet <kmo@daterainc.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
| -rw-r--r-- | include/linux/percpu-refcount.h | 4 | ||||
| -rw-r--r-- | lib/percpu-refcount.c | 2 |
2 files changed, 2 insertions, 4 deletions
diff --git a/include/linux/percpu-refcount.h b/include/linux/percpu-refcount.h index 5d8920e23073..bfdeb0d48e21 100644 --- a/include/linux/percpu-refcount.h +++ b/include/linux/percpu-refcount.h @@ -88,12 +88,10 @@ static inline void percpu_ref_kill(struct percpu_ref *ref) return percpu_ref_kill_and_confirm(ref, NULL); } -#define PCPU_STATUS_BITS 2 -#define PCPU_STATUS_MASK ((1 << PCPU_STATUS_BITS) - 1) #define PCPU_REF_PTR 0 #define PCPU_REF_DEAD 1 -#define REF_STATUS(count) (((unsigned long) count) & PCPU_STATUS_MASK) +#define REF_STATUS(count) (((unsigned long) count) & PCPU_REF_DEAD) /** * percpu_ref_get - increment a percpu refcount diff --git a/lib/percpu-refcount.c b/lib/percpu-refcount.c index 963b7034a51b..17bce2bccc14 100644 --- a/lib/percpu-refcount.c +++ b/lib/percpu-refcount.c @@ -96,7 +96,7 @@ static void percpu_ref_kill_rcu(struct rcu_head *rcu) /* Mask out PCPU_REF_DEAD */ pcpu_count = (unsigned __percpu *) - (((unsigned long) pcpu_count) & ~PCPU_STATUS_MASK); + (((unsigned long) pcpu_count) & ~PCPU_REF_DEAD); for_each_possible_cpu(cpu) count += *per_cpu_ptr(pcpu_count, cpu); |