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 <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 25cac5f..50a804b 100644
--- a/fs/select.c
+++ b/fs/select.c
@@ -403,8 +403,7 @@
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 @@
}
/* 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 @@
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 @@
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