diff options
| -rw-r--r-- | fs/select.c | 10 | ||||
| -rw-r--r-- | include/linux/jiffies.h | 4 | ||||
| -rw-r--r-- | include/net/ll_poll.h | 26 |
3 files changed, 27 insertions, 13 deletions
diff --git a/fs/select.c b/fs/select.c index 36540754bad..f28a5859272 100644 --- a/fs/select.c +++ b/fs/select.c @@ -403,7 +403,8 @@ int do_select(int n, fd_set_bits *fds, struct timespec *end_time) int retval, i, timed_out = 0; unsigned long slack = 0; unsigned int ll_flag = ll_get_flag(); - u64 ll_time = ll_end_time(); + u64 ll_start = ll_start_time(ll_flag); + u64 ll_time = ll_run_time(); rcu_read_lock(); retval = max_select_fd(n, fds); @@ -498,7 +499,7 @@ int do_select(int n, fd_set_bits *fds, struct timespec *end_time) } /* only if on, have sockets with POLL_LL and not out of time */ - if (ll_flag && can_ll && can_poll_ll(ll_time)) + if (ll_flag && can_ll && can_poll_ll(ll_start, ll_time)) continue; /* @@ -770,7 +771,8 @@ static int do_poll(unsigned int nfds, struct poll_list *list, int timed_out = 0, count = 0; unsigned long slack = 0; unsigned int ll_flag = ll_get_flag(); - u64 ll_time = ll_end_time(); + u64 ll_start = ll_start_time(ll_flag); + u64 ll_time = ll_run_time(); /* Optimise the no-wait case */ if (end_time && !end_time->tv_sec && !end_time->tv_nsec) { @@ -819,7 +821,7 @@ static int do_poll(unsigned int nfds, struct poll_list *list, break; /* only if on, have sockets with POLL_LL and not out of time */ - if (ll_flag && can_ll && can_poll_ll(ll_time)) + if (ll_flag && can_ll && can_poll_ll(ll_start, ll_time)) continue; /* diff --git a/include/linux/jiffies.h b/include/linux/jiffies.h index 8fb8edf1241..97ba4e78a37 100644 --- a/include/linux/jiffies.h +++ b/include/linux/jiffies.h @@ -139,6 +139,10 @@ static inline u64 get_jiffies_64(void) ((__s64)(a) - (__s64)(b) >= 0)) #define time_before_eq64(a,b) time_after_eq64(b,a) +#define time_in_range64(a, b, c) \ + (time_after_eq64(a, b) && \ + time_before_eq64(a, c)) + /* * These four macros compare jiffies and 'a' for convenience. */ diff --git a/include/net/ll_poll.h b/include/net/ll_poll.h index 6c06f7c0a22..b76f004f18a 100644 --- a/include/net/ll_poll.h +++ b/include/net/ll_poll.h @@ -67,19 +67,23 @@ 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_end_time(struct sock *sk) +static inline u64 ll_sk_run_time(struct sock *sk) { - return ((u64)ACCESS_ONCE(sk->sk_ll_usec) << 10) + ll_sched_clock(); + return (u64)ACCESS_ONCE(sk->sk_ll_usec) << 10; } /* in poll/select we use the global sysctl_net_ll_poll value * only call sched_clock() if enabled */ -static inline u64 ll_end_time(void) +static inline u64 ll_run_time(void) { - u64 end_time = ACCESS_ONCE(sysctl_net_ll_poll); + return (u64)ACCESS_ONCE(sysctl_net_ll_poll) << 10; +} - return end_time ? (end_time << 10) + ll_sched_clock() : 0; +/* if flag is not set we don't need to know the time */ +static inline u64 ll_start_time(unsigned int flag) +{ + return flag ? ll_sched_clock() : 0; } static inline bool sk_valid_ll(struct sock *sk) @@ -88,9 +92,12 @@ static inline bool sk_valid_ll(struct sock *sk) !need_resched() && !signal_pending(current); } -static inline bool can_poll_ll(u64 end_time) +/* careful! time_in_range64 will evaluate now twice */ +static inline bool can_poll_ll(u64 start_time, u64 run_time) { - return !time_after64(ll_sched_clock(), end_time); + u64 now = ll_sched_clock(); + + return time_in_range64(now, start_time, start_time + run_time); } /* when used in sock_poll() nonblock is known at compile time to be true @@ -98,7 +105,8 @@ static inline bool can_poll_ll(u64 end_time) */ static inline bool sk_poll_ll(struct sock *sk, int nonblock) { - u64 end_time = nonblock ? 0 : ll_sk_end_time(sk); + u64 start_time = ll_start_time(!nonblock); + u64 run_time = ll_sk_run_time(sk); const struct net_device_ops *ops; struct napi_struct *napi; int rc = false; @@ -129,7 +137,7 @@ 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(end_time)); + can_poll_ll(start_time, run_time)); rc = !skb_queue_empty(&sk->sk_receive_queue); out: |