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 /init | |
| 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 'init')
| -rw-r--r-- | init/Kconfig | 28 |
1 files changed, 28 insertions, 0 deletions
diff --git a/init/Kconfig b/init/Kconfig index f5becd2a12f..0eda68f0ad5 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -763,3 +763,31 @@ source "block/Kconfig" config PREEMPT_NOTIFIERS bool + +choice + prompt "RCU implementation type:" + default CLASSIC_RCU + +config CLASSIC_RCU + bool "Classic RCU" + help + This option selects the classic RCU implementation that is + designed for best read-side performance on non-realtime + systems. + + Say Y if you are unsure. + +config PREEMPT_RCU + bool "Preemptible RCU" + depends on PREEMPT + help + This option reduces the latency of the kernel by making certain + RCU sections preemptible. Normally RCU code is non-preemptible, if + this option is selected then read-only RCU sections become + preemptible. This helps latency, but may expose bugs due to + now-naive assumptions about each RCU read-side critical section + remaining on a given CPU through its execution. + + Say N if you are unsure. + +endchoice |