K 10
svn:author
V 7
dchagin
K 8
svn:date
V 27
2021-03-21T07:08:22.252955Z
K 7
svn:log
V 1009
linux: make timerfd_settime(2) set expirations count to zero

On Linux, read(2) from a timerfd file descriptor returns an unsigned
8-byte integer (uint64_t) containing the number of expirations
that have occurred, if the timer has already expired one or more
times since its settings were last modified using timerfd_settime(),
or since the last successful read(2).  That's to say, once we do
a read or call timerfd_settime(), timer fd's expiration count should
be zero.  Some Linux applications create timerfd and add it to epoll
with LT mode, when event comes, they do timerfd_settime instead
of read to stop event source from trigger.  On FreeBSD,
timerfd_settime(2) didn't set the count to zero, which caused high
CPU utilization.

PR:		252820
Submitted by:	ankohuu_outlook.com (Shunchao Hu)
Differential Revision: https://reviews.freebsd.org/D28231

(cherry picked from commit ae71b794cbed19e5e25effc3438720ad452ab87c)

Git Hash:   bf1863de6b1fb813192e45639b4cfde65a624b6b
Git Author: ankohuu@outlook.com
END