• Frederic Weisbecker's avatar
    x86: Call idle notifier after irq_enter() · 98ad1cc1
    Frederic Weisbecker authored
    Interrupts notify the idle exit state before calling irq_enter().
    But the notifier code calls rcu_read_lock() and this is not
    allowed while rcu is in an extended quiescent state. We need
    to wait for irq_enter() -> rcu_idle_exit() to be called before
    doing so otherwise this results in a grumpy RCU:
    
    [    0.099991] WARNING: at include/linux/rcupdate.h:194 __atomic_notifier_call_chain+0xd2/0x110()
    [    0.099991] Hardware name: AMD690VM-FMH
    [    0.099991] Modules linked in:
    [    0.099991] Pid: 0, comm: swapper Not tainted 3.0.0-rc6+ #255
    [    0.099991] Call Trace:
    [    0.099991]  <IRQ>  [<ffffffff81051c8a>] warn_slowpath_common+0x7a/0xb0
    [    0.099991]  [<ffffffff81051cd5>] warn_slowpath_null+0x15/0x20
    [    0.099991]  [<ffffffff817d6fa2>] __atomic_notifier_call_chain+0xd2/0x110
    [    0.099991]  [<ffffffff817d6ff1>] atomic_notifier_call_chain+0x11/0x20
    [    0.099991]  [<ffffffff81001873>] exit_idle+0x43/0x50
    [    0.099991]  [<ffffffff81020439>] smp_apic_timer_interrupt+0x39/0xa0
    [    0.099991]  [<ffffffff817da253>] apic_timer_interrupt+0x13/0x20
    [    0.099991]  <EOI>  [<ffffffff8100ae67>] ? default_idle+0xa7/0x350
    [    0.099991]  [<ffffffff8100ae65>] ? default_idle+0xa5/0x350
    [    0.099991]  [<ffffffff8100b19b>] amd_e400_idle+0x8b/0x110
    [    0.099991]  [<ffffffff810cb01f>] ? rcu_enter_nohz+0x8f/0x160
    [    0.099991]  [<ffffffff810019a0>] cpu_idle+0xb0/0x110
    [    0.099991]  [<ffffffff817a7505>] rest_init+0xe5/0x140
    [    0.099991]  [<ffffffff817a7468>] ? rest_init+0x48/0x140
    [    0.099991]  [<ffffffff81cc5ca3>] start_kernel+0x3d1/0x3dc
    [    0.099991]  [<ffffffff81cc5321>] x86_64_start_reservations+0x131/0x135
    [    0.099991]  [<ffffffff81cc5412>] x86_64_start_kernel+0xed/0xf4
    Signed-off-by: default avatarFrederic 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>
    Cc: Andy Henroid <andrew.d.henroid@intel.com>
    Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
    Reviewed-by: default avatarJosh Triplett <josh@joshtriplett.org>
    98ad1cc1
threshold.c 641 Bytes