2.6.37-stable review patch. If anyone has any objections, please let us know.
------------------ From: Eric Dumazet <[email protected]> commit 0781b909b5586f4db720b5d1838b78f9d8e42f14 upstream. commit 95aac7b1cd224f ("epoll: make epoll_wait() use the hrtimer range feature") added a performance regression because it uses timespec_add_ns() with potential very large 'ns' values. [[email protected]: s/epoll_set_mstimeout/ep_set_mstimeout/, per Davide] Reported-by: Simon Kirby <[email protected]> Signed-off-by: Eric Dumazet <[email protected]> Cc: Shawn Bohrer <[email protected]> Acked-by: Davide Libenzi <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- fs/eventpoll.c | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-) --- a/fs/eventpoll.c +++ b/fs/eventpoll.c @@ -1111,6 +1111,17 @@ static int ep_send_events(struct eventpo return ep_scan_ready_list(ep, ep_send_events_proc, &esed); } +static inline struct timespec ep_set_mstimeout(long ms) +{ + struct timespec now, ts = { + .tv_sec = ms / MSEC_PER_SEC, + .tv_nsec = NSEC_PER_MSEC * (ms % MSEC_PER_SEC), + }; + + ktime_get_ts(&now); + return timespec_add_safe(now, ts); +} + static int ep_poll(struct eventpoll *ep, struct epoll_event __user *events, int maxevents, long timeout) { @@ -1118,12 +1129,11 @@ static int ep_poll(struct eventpoll *ep, unsigned long flags; long slack; wait_queue_t wait; - struct timespec end_time; ktime_t expires, *to = NULL; if (timeout > 0) { - ktime_get_ts(&end_time); - timespec_add_ns(&end_time, (u64)timeout * NSEC_PER_MSEC); + struct timespec end_time = ep_set_mstimeout(timeout); + slack = select_estimate_accuracy(&end_time); to = &expires; *to = timespec_to_ktime(end_time); _______________________________________________ stable mailing list [email protected] http://linux.kernel.org/mailman/listinfo/stable
