diff options
| author | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2008-01-25 21:08:24 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2008-01-25 21:08:24 +0100 |
| commit | e260be673a15b6125068270e0216a3bfbfc12f87 (patch) | |
| tree | f50760606d395bf6faa9e865f814761a3c88d32c /include/linux/rcupdate.h | |
| parent | e0ecfa7917cafe72f4a75f87e8bb5d8d51dc534f (diff) | |
Preempt-RCU: implementation
This patch implements a new version of RCU which allows its read-side
critical sections to be preempted. It uses a set of counter pairs
to keep track of the read-side critical sections and flips them
when all tasks exit read-side critical section. The details
of this implementation can be found in this paper -
http://www.rdrop.com/users/paulmck/RCU/OLSrtRCU.2006.08.11a.pdf
and the article-
http://lwn.net/Articles/253651/
This patch was developed as a part of the -rt kernel development and
meant to provide better latencies when read-side critical sections of
RCU don't disable preemption. As a consequence of keeping track of RCU
readers, the readers have a slight overhead (optimizations in the paper).
This implementation co-exists with the "classic" RCU implementations
and can be switched to at compiler.
Also includes RCU tracing summarized in debugfs.
[ akpm@linux-foundation.org: build fixes on non-preempt architectures ]
Signed-off-by: Gautham R Shenoy <ego@in.ibm.com>
Signed-off-by: Dipankar Sarma <dipankar@in.ibm.com>
Signed-off-by: Paul E. McKenney <paulmck@us.ibm.com>
Reviewed-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'include/linux/rcupdate.h')
| -rw-r--r-- | include/linux/rcupdate.h | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h index 12aa13e13150..d32c14de270e 100644 --- a/include/linux/rcupdate.h +++ b/include/linux/rcupdate.h @@ -53,7 +53,11 @@ struct rcu_head { void (*func)(struct rcu_head *head); }; +#ifdef CONFIG_CLASSIC_RCU #include <linux/rcuclassic.h> +#else /* #ifdef CONFIG_CLASSIC_RCU */ +#include <linux/rcupreempt.h> +#endif /* #else #ifdef CONFIG_CLASSIC_RCU */ #define RCU_HEAD_INIT { .next = NULL, .func = NULL } #define RCU_HEAD(head) struct rcu_head head = RCU_HEAD_INIT @@ -231,13 +235,12 @@ extern void call_rcu_bh(struct rcu_head *head, /* Exported common interfaces */ extern void synchronize_rcu(void); extern void rcu_barrier(void); +extern long rcu_batches_completed(void); +extern long rcu_batches_completed_bh(void); /* Internal to kernel */ extern void rcu_init(void); -extern void rcu_check_callbacks(int cpu, int user); - -extern long rcu_batches_completed(void); -extern long rcu_batches_completed_bh(void); +extern int rcu_needs_cpu(int cpu); #endif /* __KERNEL__ */ #endif /* __LINUX_RCUPDATE_H */ |