diff options
| author | Frederic Weisbecker <fweisbec@gmail.com> | 2011-10-07 18:22:08 +0200 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2011-12-11 19:31:37 +0100 |
| commit | e37e112de3ac64032df45c2db0dbe1e8f1af86b4 (patch) | |
| tree | 688ac406d7edb9766f07aa7dd308d62ae1d73044 /arch | |
| parent | nohz: Allow rcu extended quiescent state handling seperately from tick stop (diff) | |
| download | linux-e37e112de3ac64032df45c2db0dbe1e8f1af86b4.tar.xz linux-e37e112de3ac64032df45c2db0dbe1e8f1af86b4.zip | |
x86: Enter rcu extended qs after idle notifier call
The idle notifier, called by enter_idle(), enters into rcu read
side critical section but at that time we already switched into
the RCU-idle window (rcu_idle_enter() has been called). And it's
illegal to use rcu_read_lock() in that state.
This results in rcu reporting its bad mood:
[ 1.275635] WARNING: at include/linux/rcupdate.h:194 __atomic_notifier_call_chain+0xd2/0x110()
[ 1.275635] Hardware name: AMD690VM-FMH
[ 1.275635] Modules linked in:
[ 1.275635] Pid: 0, comm: swapper Not tainted 3.0.0-rc6+ #252
[ 1.275635] Call Trace:
[ 1.275635] [<ffffffff81051c8a>] warn_slowpath_common+0x7a/0xb0
[ 1.275635] [<ffffffff81051cd5>] warn_slowpath_null+0x15/0x20
[ 1.275635] [<ffffffff817d6f22>] __atomic_notifier_call_chain+0xd2/0x110
[ 1.275635] [<ffffffff817d6f71>] atomic_notifier_call_chain+0x11/0x20
[ 1.275635] [<ffffffff810018a0>] enter_idle+0x20/0x30
[ 1.275635] [<ffffffff81001995>] cpu_idle+0xa5/0x110
[ 1.275635] [<ffffffff817a7465>] rest_init+0xe5/0x140
[ 1.275635] [<ffffffff817a73c8>] ? rest_init+0x48/0x140
[ 1.275635] [<ffffffff81cc5ca3>] start_kernel+0x3d1/0x3dc
[ 1.275635] [<ffffffff81cc5321>] x86_64_start_reservations+0x131/0x135
[ 1.275635] [<ffffffff81cc5412>] x86_64_start_kernel+0xed/0xf4
[ 1.275635] ---[ end trace a22d306b065d4a66 ]---
Fix this by entering rcu extended quiescent state later, just before
the CPU goes to sleep.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/kernel/process_64.c | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c index 18e8cf3581f6..64e926c89a6f 100644 --- a/arch/x86/kernel/process_64.c +++ b/arch/x86/kernel/process_64.c @@ -122,7 +122,7 @@ void cpu_idle(void) /* endless idle loop with no priority at all */ while (1) { - tick_nohz_idle_enter_norcu(); + tick_nohz_idle_enter(); while (!need_resched()) { rmb(); @@ -139,8 +139,14 @@ void cpu_idle(void) enter_idle(); /* Don't trace irqs off for idle */ stop_critical_timings(); + + /* enter_idle() needs rcu for notifiers */ + rcu_idle_enter(); + if (cpuidle_idle_call()) pm_idle(); + + rcu_idle_exit(); start_critical_timings(); /* In many cases the interrupt that ended idle @@ -149,7 +155,7 @@ void cpu_idle(void) __exit_idle(); } - tick_nohz_idle_exit_norcu(); + tick_nohz_idle_exit(); preempt_enable_no_resched(); schedule(); preempt_disable(); |