net: avoid calling sched_clock when LLS is off
Change Low Latency Sockets code for select and poll so that
when LLS is disabled sched_clock() is never called.
Also, avoid sending POLL_LL to sockets if disabled.
Reported-by: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Eliezer Tamir <eliezer.tamir@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/fs/select.c b/fs/select.c
index 79b876e..3654075 100644
--- a/fs/select.c
+++ b/fs/select.c
@@ -402,7 +402,7 @@
poll_table *wait;
int retval, i, timed_out = 0;
unsigned long slack = 0;
- unsigned int ll_flag = POLL_LL;
+ unsigned int ll_flag = ll_get_flag();
u64 ll_time = ll_end_time();
rcu_read_lock();
@@ -497,7 +497,8 @@
break;
}
- if (can_ll && can_poll_ll(ll_time))
+ /* only if on, have sockets with POLL_LL and not out of time */
+ if (ll_flag && can_ll && can_poll_ll(ll_time))
continue;
/*
@@ -768,7 +769,7 @@
ktime_t expire, *to = NULL;
int timed_out = 0, count = 0;
unsigned long slack = 0;
- unsigned int ll_flag = POLL_LL;
+ unsigned int ll_flag = ll_get_flag();
u64 ll_time = ll_end_time();
/* Optimise the no-wait case */
@@ -817,8 +818,10 @@
if (count || timed_out)
break;
- if (can_ll && can_poll_ll(ll_time))
+ /* only if on, have sockets with POLL_LL and not out of time */
+ if (ll_flag && can_ll && can_poll_ll(ll_time))
continue;
+
/*
* If this is the first loop and we have a timeout
* given, then we convert to ktime_t and set the to