From 76b1e9b9813e412bde7446525f6c299803713545 Mon Sep 17 00:00:00 2001 From: Eliezer Tamir Date: Tue, 9 Jul 2013 13:09:21 +0300 Subject: net/fs: change busy poll time accounting Suggested by Linus: Changed time accounting for busy-poll: - Make it microsecond based. - Use unsigned longs. - Revert back to use time_after instead of time_in_range. Reorder poll/select busy loop conditions: - Clear busy_flag after one time we can't busy-poll. - Only init busy_end if we actually are going to busy-poll. Added one more missing need_resched() test. Signed-off-by: Eliezer Tamir Signed-off-by: David S. Miller --- fs/select.c | 31 ++++++++++++++++++++----------- 1 file changed, 20 insertions(+), 11 deletions(-) (limited to 'fs/select.c') diff --git a/fs/select.c b/fs/select.c index 25cac5faf6d6..50a804b6839f 100644 --- a/fs/select.c +++ b/fs/select.c @@ -403,8 +403,7 @@ 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 busy_flag = net_busy_loop_on() ? POLL_BUSY_LOOP : 0; - u64 busy_start = busy_loop_start_time(busy_flag); - u64 busy_end = busy_loop_end_time(); + unsigned long busy_end = 0; rcu_read_lock(); retval = max_select_fd(n, fds); @@ -506,9 +505,15 @@ int do_select(int n, fd_set_bits *fds, struct timespec *end_time) } /* only if found POLL_BUSY_LOOP sockets && not out of time */ - if (!need_resched() && can_busy_loop && - busy_loop_range(busy_start, busy_end)) - continue; + if (can_busy_loop && !need_resched()) { + if (!busy_end) { + busy_end = busy_loop_end_time(); + continue; + } + if (!busy_loop_timeout(busy_end)) + continue; + } + busy_flag = 0; /* * If this is the first loop and we have a timeout @@ -780,9 +785,7 @@ static int do_poll(unsigned int nfds, struct poll_list *list, int timed_out = 0, count = 0; unsigned long slack = 0; unsigned int busy_flag = net_busy_loop_on() ? POLL_BUSY_LOOP : 0; - u64 busy_start = busy_loop_start_time(busy_flag); - u64 busy_end = busy_loop_end_time(); - + unsigned long busy_end = 0; /* Optimise the no-wait case */ if (end_time && !end_time->tv_sec && !end_time->tv_nsec) { @@ -834,9 +837,15 @@ static int do_poll(unsigned int nfds, struct poll_list *list, break; /* only if found POLL_BUSY_LOOP sockets && not out of time */ - if (!need_resched() && can_busy_loop && - busy_loop_range(busy_start, busy_end)) - continue; + if (can_busy_loop && !need_resched()) { + if (!busy_end) { + busy_end = busy_loop_end_time(); + continue; + } + if (!busy_loop_timeout(busy_end)) + continue; + } + busy_flag = 0; /* * If this is the first loop and we have a timeout -- cgit v1.2.3