xen pvfb: Zero unused bytes in events sent to backend

[safe/jmp/linux-2.6] / kernel / Kconfig.preempt

diff --git a/kernel/Kconfig.preempt b/kernel/Kconfig.preempt
index 0b46a5d..9fdba03 100644 (file)
--- a/kernel/Kconfig.preempt
+++ b/kernel/Kconfig.preempt
@@ -23,7 +23,7 @@ config PREEMPT_VOLUNTARY
          "explicit preemption points" to the kernel code. These new
          preemption points have been selected to reduce the maximum
          latency of rescheduling, providing faster application reactions,
-         at the cost of slighly lower throughput.
+         at the cost of slightly lower throughput.
 
          This allows reaction to interactive events by allowing a
          low priority process to voluntarily preempt itself even if it
@@ -43,7 +43,7 @@ config PREEMPT
          even if it is in kernel mode executing a system call and would
          otherwise not be about to reach a natural preemption point.
          This allows applications to run more 'smoothly' even when the
-         system is under load, at the cost of slighly lower throughput
+         system is under load, at the cost of slightly lower throughput
          and a slight runtime overhead to kernel code.
 
          Select this if you are building a kernel for a desktop or
@@ -52,14 +52,28 @@ config PREEMPT
 
 endchoice
 
-config PREEMPT_BKL
-       bool "Preempt The Big Kernel Lock"
-       depends on SMP || PREEMPT
-       default y
+config PREEMPT_RCU
+       bool "Preemptible RCU"
+       depends on PREEMPT
+       default n
        help
-         This option reduces the latency of the kernel by making the
-         big kernel lock preemptible.
+         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 Y here if you are building a kernel for a desktop system.
          Say N if you are unsure.
 
+config RCU_TRACE
+       bool "Enable tracing for RCU - currently stats in debugfs"
+       depends on PREEMPT_RCU
+       select DEBUG_FS
+       default y
+       help
+         This option provides tracing in RCU which presents stats
+         in debugfs for debugging RCU implementation.
+
+         Say Y here if you want to enable RCU tracing
+         Say N if you are unsure.