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OpenCloudOS-Kernel
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context_tracking: Run vtime_user_enter/exit only when state == CONTEXT_USER 

Only run vtime_user_enter, vtime_user_exit, and the user enter & exit
trace points when we are entering or exiting user state, respectively.

The KVM code in guest_enter and guest_exit already take care of calling
vtime_guest_enter and vtime_guest_exit, respectively.

The RCU code only distinguishes between "idle" and "not idle or kernel".
There should be no need to add an additional (unused) state there.

Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Rik van Riel <riel@redhat.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Will deacon <will.deacon@arm.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Luiz Capitulino <lcapitulino@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
This commit is contained in:
Rik van Riel 2015-02-10 15:27:52 -05:00 committed by Frederic Weisbecker
parent a3a9c7dff2
commit 19fdd98b62
1 changed files with 8 additions and 4 deletions
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12
kernel/context_tracking.c
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@ -77,7 +77,6 @@ void context_tracking_enter(enum ctx_state state)
local_irq_save(flags);
if ( __this_cpu_read(context_tracking.state) != state) {
if (__this_cpu_read(context_tracking.active)) {
trace_user_enter(0);
/*
* At this stage, only low level arch entry code remains and
* then we'll run in userspace. We can assume there won't be
@ -85,7 +84,10 @@ void context_tracking_enter(enum ctx_state state)
* user_exit() or rcu_irq_enter(). Let's remove RCU's dependency
* on the tick.
*/
vtime_user_enter(current);
if (state == CONTEXT_USER) {
trace_user_enter(0);
vtime_user_enter(current);
}
rcu_user_enter();
}
/*
@ -143,8 +145,10 @@ void context_tracking_exit(enum ctx_state state)
* RCU core about that (ie: we may need the tick again).
*/
rcu_user_exit();
vtime_user_exit(current);
trace_user_exit(0);
if (state == CONTEXT_USER) {
vtime_user_exit(current);
trace_user_exit(0);
}
}
__this_cpu_write(context_tracking.state, CONTEXT_KERNEL);
}