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authorFrederic Weisbecker <fweisbec@gmail.com>2012-12-16 20:00:34 +0100
committerFrederic Weisbecker <fweisbec@gmail.com>2013-01-27 20:35:47 +0100
commit6a61671bb2f3a1bd12cd17b8fca811a624782632 (patch)
tree0afc2915fb7e517472710a49a524510322dd5baa /kernel/softirq.c
parentc11f11fcbdb5be790c565aed46411486a7586afc (diff)
downloadop-kernel-dev-6a61671bb2f3a1bd12cd17b8fca811a624782632.zip
op-kernel-dev-6a61671bb2f3a1bd12cd17b8fca811a624782632.tar.gz
cputime: Safely read cputime of full dynticks CPUs
While remotely reading the cputime of a task running in a full dynticks CPU, the values stored in utime/stime fields of struct task_struct may be stale. Its values may be those of the last kernel <-> user transition time snapshot and we need to add the tickless time spent since this snapshot. To fix this, flush the cputime of the dynticks CPUs on kernel <-> user transition and record the time / context where we did this. Then on top of this snapshot and the current time, perform the fixup on the reader side from task_times() accessors. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Li Zhong <zhong@linux.vnet.ibm.com> Cc: Namhyung Kim <namhyung.kim@lge.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> [fixed kvm module related build errors] Signed-off-by: Sedat Dilek <sedat.dilek@gmail.com>
Diffstat (limited to 'kernel/softirq.c')
-rw-r--r--kernel/softirq.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/kernel/softirq.c b/kernel/softirq.c
index ed567ba..f5cc25f 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -221,7 +221,7 @@ asmlinkage void __do_softirq(void)
current->flags &= ~PF_MEMALLOC;
pending = local_softirq_pending();
- vtime_account_irq_enter(current);
+ account_irq_enter_time(current);
__local_bh_disable((unsigned long)__builtin_return_address(0),
SOFTIRQ_OFFSET);
@@ -272,7 +272,7 @@ restart:
lockdep_softirq_exit();
- vtime_account_irq_exit(current);
+ account_irq_exit_time(current);
__local_bh_enable(SOFTIRQ_OFFSET);
tsk_restore_flags(current, old_flags, PF_MEMALLOC);
}
@@ -341,7 +341,7 @@ static inline void invoke_softirq(void)
*/
void irq_exit(void)
{
- vtime_account_irq_exit(current);
+ account_irq_exit_time(current);
trace_hardirq_exit();
sub_preempt_count(IRQ_EXIT_OFFSET);
if (!in_interrupt() && local_softirq_pending())
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