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authorPaul E. McKenney <paulmck@linux.vnet.ibm.com>2008-01-25 15:08:24 -0500
committerIngo Molnar <mingo@elte.hu>2008-01-25 15:08:24 -0500
commite260be673a15b6125068270e0216a3bfbfc12f87 (patch)
treef50760606d395bf6faa9e865f814761a3c88d32c /kernel/Kconfig.preempt
parente0ecfa7917cafe72f4a75f87e8bb5d8d51dc534f (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 'kernel/Kconfig.preempt')
-rw-r--r--kernel/Kconfig.preempt10
1 files changed, 10 insertions, 0 deletions
diff --git a/kernel/Kconfig.preempt b/kernel/Kconfig.preempt
index c64ce9c14207..61fa116efcde 100644
--- a/kernel/Kconfig.preempt
+++ b/kernel/Kconfig.preempt
@@ -63,3 +63,13 @@ config PREEMPT_BKL
63 Say Y here if you are building a kernel for a desktop system. 63 Say Y here if you are building a kernel for a desktop system.
64 Say N if you are unsure. 64 Say N if you are unsure.
65 65
66config RCU_TRACE
67 bool "Enable tracing for RCU - currently stats in debugfs"
68 select DEBUG_FS
69 default y
70 help
71 This option provides tracing in RCU which presents stats
72 in debugfs for debugging RCU implementation.
73
74 Say Y here if you want to enable RCU tracing
75 Say N if you are unsure.