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| author | Frederic Weisbecker <fweisbec@gmail.com> | 2015-05-06 18:04:24 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2015-05-07 12:02:51 +0200 |
| commit | fafe870f31212a72f3c2d74e7b90e4ef39e83ee1 (patch) | |
| tree | c1b1ef375b480b26a827c3c6eb12eb2de7ed164a /kernel/sched | |
| parent | aed5ed47724f6a7453fa62e3c90f3cee93edbfe3 (diff) | |
| download | linux-fafe870f31212a72f3c2d74e7b90e4ef39e83ee1.tar.gz linux-fafe870f31212a72f3c2d74e7b90e4ef39e83ee1.tar.bz2 linux-fafe870f31212a72f3c2d74e7b90e4ef39e83ee1.zip | |
context_tracking: Inherit TIF_NOHZ through forks instead of context switches
TIF_NOHZ is used by context_tracking to force syscall slow-path
on every task in order to track userspace roundtrips. As such,
it must be set on all running tasks.
It's currently explicitly inherited through context switches.
There is no need to do it in this fast-path though. The flag
could simply be set once for all on all tasks, whether they are
running or not.
Lets do this by setting the flag for the init task on early boot,
and let it propagate through fork inheritance.
While at it, mark context_tracking_cpu_set() as init code, we
only need it at early boot time.
Suggested-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Dave Jones <davej@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Mike Galbraith <umgwanakikbuti@gmail.com>
Cc: Paul E . McKenney <paulmck@linux.vnet.ibm.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rafael J . Wysocki <rafael.j.wysocki@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1430928266-24888-3-git-send-email-fweisbec@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/sched')
| -rw-r--r-- | kernel/sched/core.c | 1 |
1 files changed, 0 insertions, 1 deletions
diff --git a/kernel/sched/core.c b/kernel/sched/core.c index fe22f7510bce..54f032cea040 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -2332,7 +2332,6 @@ context_switch(struct rq *rq, struct task_struct *prev, */ spin_release(&rq->lock.dep_map, 1, _THIS_IP_); - context_tracking_task_switch(prev, next); /* Here we just switch the register state and the stack. */ switch_to(prev, next, prev); barrier(); |