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| author | Dipankar Sarma <dipankar@in.ibm.com> | 2005-09-09 13:04:09 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2005-09-09 13:57:54 -0700 |
| commit | c0dfb2905126e9e94edebbce8d3e05001301f52d (patch) | |
| tree | db31f15f7e5dea0c812992c2ca87a1151507ed9c /kernel/rcupdate.c | |
| parent | 8b6490e5faafb3a16ea45654fb55f9ff086f1495 (diff) | |
| download | lwn-c0dfb2905126e9e94edebbce8d3e05001301f52d.tar.gz lwn-c0dfb2905126e9e94edebbce8d3e05001301f52d.zip | |
[PATCH] files: rcuref APIs
Adds a set of primitives to do reference counting for objects that are looked
up without locks using RCU.
Signed-off-by: Ravikiran Thirumalai <kiran_th@gmail.com>
Signed-off-by: Dipankar Sarma <dipankar@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'kernel/rcupdate.c')
| -rw-r--r-- | kernel/rcupdate.c | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/kernel/rcupdate.c b/kernel/rcupdate.c index f436993bd590..bef3b6901b76 100644 --- a/kernel/rcupdate.c +++ b/kernel/rcupdate.c @@ -45,6 +45,7 @@ #include <linux/percpu.h> #include <linux/notifier.h> #include <linux/rcupdate.h> +#include <linux/rcuref.h> #include <linux/cpu.h> /* Definition for rcupdate control block. */ @@ -72,6 +73,19 @@ DEFINE_PER_CPU(struct rcu_data, rcu_bh_data) = { 0L }; static DEFINE_PER_CPU(struct tasklet_struct, rcu_tasklet) = {NULL}; static int maxbatch = 10; +#ifndef __HAVE_ARCH_CMPXCHG +/* + * We use an array of spinlocks for the rcurefs -- similar to ones in sparc + * 32 bit atomic_t implementations, and a hash function similar to that + * for our refcounting needs. + * Can't help multiprocessors which donot have cmpxchg :( + */ + +spinlock_t __rcuref_hash[RCUREF_HASH_SIZE] = { + [0 ... (RCUREF_HASH_SIZE-1)] = SPIN_LOCK_UNLOCKED +}; +#endif + /** * call_rcu - Queue an RCU callback for invocation after a grace period. * @head: structure to be used for queueing the RCU updates. |