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authorLinus Torvalds <torvalds@linux-foundation.org>2012-10-01 10:16:42 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2012-10-01 10:16:42 -0700
commit620e77533f29796df7aff861e79bd72e08554ebb (patch)
tree844afce2333549bc5b8d7dc87a4875b9216a0023 /arch/um
parent6977b4c7736e8809b7959c66875a16c0bbcf2152 (diff)
parentfa34da708cbe1e2d9a2ee7fc68ea8fccbf095d12 (diff)
Merge branch 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull RCU changes from Ingo Molnar: 0. 'idle RCU': Adds RCU APIs that allow non-idle tasks to enter RCU idle mode and provides x86 code to make use of them, allowing RCU to treat user-mode execution as an extended quiescent state when the new RCU_USER_QS kernel configuration parameter is specified. (Work is in progress to port this to a few other architectures, but is not part of this series.) 1. A fix for a latent bug that has been in RCU ever since the addition of CPU stall warnings. This bug results in false-positive stall warnings, but thus far only on embedded systems with severely cut-down userspace configurations. 2. Further reductions in latency spikes for huge systems, along with additional boot-time adaptation to the actual hardware. This is a large change, as it moves RCU grace-period initialization and cleanup, along with quiescent-state forcing, from softirq to a kthread. However, it appears to be in quite good shape (famous last words). 3. Updates to documentation and rcutorture, the latter category including keeping statistics on CPU-hotplug latencies and fixing some initialization-time races. 4. CPU-hotplug fixes and improvements. 5. Idle-loop fixes that were omitted on an earlier submission. 6. Miscellaneous fixes and improvements In certain RCU configurations new kernel threads will show up (rcu_bh, rcu_sched), showing RCU processing overhead. * 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (90 commits) rcu: Apply micro-optimization and int/bool fixes to RCU's idle handling rcu: Userspace RCU extended QS selftest x86: Exit RCU extended QS on notify resume x86: Use the new schedule_user API on userspace preemption rcu: Exit RCU extended QS on user preemption rcu: Exit RCU extended QS on kernel preemption after irq/exception x86: Exception hooks for userspace RCU extended QS x86: Unspaghettize do_general_protection() x86: Syscall hooks for userspace RCU extended QS rcu: Switch task's syscall hooks on context switch rcu: Ignore userspace extended quiescent state by default rcu: Allow rcu_user_enter()/exit() to nest rcu: Settle config for userspace extended quiescent state rcu: Make RCU_FAST_NO_HZ handle adaptive ticks rcu: New rcu_user_enter_after_irq() and rcu_user_exit_after_irq() APIs rcu: New rcu_user_enter() and rcu_user_exit() APIs ia64: Add missing RCU idle APIs on idle loop xtensa: Add missing RCU idle APIs on idle loop score: Add missing RCU idle APIs on idle loop parisc: Add missing RCU idle APIs on idle loop ...
Diffstat (limited to 'arch/um')
-rw-r--r--arch/um/drivers/mconsole_kern.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/um/drivers/mconsole_kern.c b/arch/um/drivers/mconsole_kern.c
index 664a60e8dfb4..c17de0db6736 100644
--- a/arch/um/drivers/mconsole_kern.c
+++ b/arch/um/drivers/mconsole_kern.c
@@ -705,6 +705,7 @@ static void stack_proc(void *arg)
struct task_struct *from = current, *to = arg;
to->thread.saved_task = from;
+ rcu_switch(from, to);
switch_to(from, to, from);
}