net: rename low latency sockets functions to busy poll
Rename functions in include/net/ll_poll.h to busy wait.
Clarify documentation about expected power use increase.
Rename POLL_LL to POLL_BUSY_LOOP.
Add need_resched() testing to poll/select busy loops.
Note, that in select and poll can_busy_poll is dynamic and is
updated continuously to reflect the existence of supported
sockets with valid queue information.
Signed-off-by: Eliezer Tamir <eliezer.tamir@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/ll_poll.h b/include/net/ll_poll.h
index 0d620ba..f14dd88 100644
--- a/include/net/ll_poll.h
+++ b/include/net/ll_poll.h
@@ -37,9 +37,9 @@
#define LL_FLUSH_FAILED -1
#define LL_FLUSH_BUSY -2
-static inline unsigned int ll_get_flag(void)
+static inline bool net_busy_loop_on(void)
{
- return sysctl_net_ll_poll ? POLL_LL : 0;
+ return sysctl_net_ll_poll;
}
/* a wrapper to make debug_smp_processor_id() happy
@@ -47,7 +47,7 @@
* we only care that the average is bounded
*/
#ifdef CONFIG_DEBUG_PREEMPT
-static inline u64 ll_sched_clock(void)
+static inline u64 busy_loop_sched_clock(void)
{
u64 rc;
@@ -58,7 +58,7 @@
return rc;
}
#else /* CONFIG_DEBUG_PREEMPT */
-static inline u64 ll_sched_clock(void)
+static inline u64 busy_loop_sched_clock(void)
{
return sched_clock();
}
@@ -67,7 +67,7 @@
/* we don't mind a ~2.5% imprecision so <<10 instead of *1000
* sk->sk_ll_usec is a u_int so this can't overflow
*/
-static inline u64 ll_sk_run_time(struct sock *sk)
+static inline u64 sk_busy_loop_end_time(struct sock *sk)
{
return (u64)ACCESS_ONCE(sk->sk_ll_usec) << 10;
}
@@ -75,27 +75,29 @@
/* in poll/select we use the global sysctl_net_ll_poll value
* only call sched_clock() if enabled
*/
-static inline u64 ll_run_time(void)
+static inline u64 busy_loop_end_time(void)
{
return (u64)ACCESS_ONCE(sysctl_net_ll_poll) << 10;
}
-/* if flag is not set we don't need to know the time */
-static inline u64 ll_start_time(unsigned int flag)
+/* if flag is not set we don't need to know the time
+ * so we want to avoid a potentially expensive sched_clock()
+ */
+static inline u64 busy_loop_start_time(unsigned int flag)
{
- return flag ? ll_sched_clock() : 0;
+ return flag ? busy_loop_sched_clock() : 0;
}
-static inline bool sk_valid_ll(struct sock *sk)
+static inline bool sk_can_busy_loop(struct sock *sk)
{
return sk->sk_ll_usec && sk->sk_napi_id &&
!need_resched() && !signal_pending(current);
}
/* careful! time_in_range64 will evaluate now twice */
-static inline bool can_poll_ll(u64 start_time, u64 run_time)
+static inline bool busy_loop_range(u64 start_time, u64 run_time)
{
- u64 now = ll_sched_clock();
+ u64 now = busy_loop_sched_clock();
return time_in_range64(now, start_time, start_time + run_time);
}
@@ -103,10 +105,10 @@
/* when used in sock_poll() nonblock is known at compile time to be true
* so the loop and end_time will be optimized out
*/
-static inline bool sk_poll_ll(struct sock *sk, int nonblock)
+static inline bool sk_busy_loop(struct sock *sk, int nonblock)
{
- u64 start_time = ll_start_time(!nonblock);
- u64 run_time = ll_sk_run_time(sk);
+ u64 start_time = busy_loop_start_time(!nonblock);
+ u64 end_time = sk_busy_loop_end_time(sk);
const struct net_device_ops *ops;
struct napi_struct *napi;
int rc = false;
@@ -137,7 +139,7 @@
LINUX_MIB_LOWLATENCYRXPACKETS, rc);
} while (!nonblock && skb_queue_empty(&sk->sk_receive_queue) &&
- can_poll_ll(start_time, run_time));
+ busy_loop_range(start_time, end_time));
rc = !skb_queue_empty(&sk->sk_receive_queue);
out:
@@ -158,27 +160,27 @@
}
#else /* CONFIG_NET_LL_RX_POLL */
-static inline unsigned long ll_get_flag(void)
+static inline unsigned long net_busy_loop_on(void)
{
return 0;
}
-static inline u64 ll_start_time(unsigned int flag)
+static inline u64 busy_loop_start_time(unsigned int flag)
{
return 0;
}
-static inline u64 ll_run_time(void)
+static inline u64 busy_loop_end_time(void)
{
return 0;
}
-static inline bool sk_valid_ll(struct sock *sk)
+static inline bool sk_can_busy_loop(struct sock *sk)
{
return false;
}
-static inline bool sk_poll_ll(struct sock *sk, int nonblock)
+static inline bool sk_busy_poll(struct sock *sk, int nonblock)
{
return false;
}
@@ -191,7 +193,7 @@
{
}
-static inline bool can_poll_ll(u64 start_time, u64 run_time)
+static inline bool busy_loop_range(u64 start_time, u64 run_time)
{
return false;
}