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author | Eliezer Tamir <eliezer.tamir@linux.intel.com> | 2013-07-08 13:20:34 (GMT) |
---|---|---|
committer | David S. Miller <davem@davemloft.net> | 2013-07-09 02:25:45 (GMT) |
commit | cbf55001b2ddb814329735641be5d29b08c82b08 (patch) | |
tree | 110c1191f4b6699bef04ebdf45e4677c623a7ceb /include | |
parent | c7e8e8a8f7a70b343ca1e0f90a31e35ab2d16de1 (diff) | |
download | linux-fsl-qoriq-cbf55001b2ddb814329735641be5d29b08c82b08.tar.xz |
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>
Diffstat (limited to 'include')
-rw-r--r-- | include/net/ll_poll.h | 46 | ||||
-rw-r--r-- | include/uapi/asm-generic/poll.h | 2 |
2 files changed, 25 insertions, 23 deletions
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 @@ extern unsigned int sysctl_net_ll_poll __read_mostly; #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 @@ static inline unsigned int ll_get_flag(void) * 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 @@ static inline u64 ll_sched_clock(void) 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 @@ static inline u64 ll_sched_clock(void) /* 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 @@ static inline u64 ll_sk_run_time(struct sock *sk) /* 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 @@ static inline bool can_poll_ll(u64 start_time, u64 run_time) /* 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 @@ static inline bool sk_poll_ll(struct sock *sk, int nonblock) 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 @@ static inline void sk_mark_ll(struct sock *sk, struct sk_buff *skb) } #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 void sk_mark_ll(struct sock *sk, struct sk_buff *skb) { } -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; } diff --git a/include/uapi/asm-generic/poll.h b/include/uapi/asm-generic/poll.h index 4aee586..a969498 100644 --- a/include/uapi/asm-generic/poll.h +++ b/include/uapi/asm-generic/poll.h @@ -30,7 +30,7 @@ #define POLLFREE 0x4000 /* currently only for epoll */ -#define POLL_LL 0x8000 +#define POLL_BUSY_LOOP 0x8000 struct pollfd { int fd; |