Hi,
I was doing epoll_wait calls with timeout values of over an hour and I was
wondering why the call never returned. Then I read the code in
fs/eventpoll.c:
#define EP_MAX_MSTIMEO min(1000ULL * MAX_SCHEDULE_TIMEOUT / HZ, (LONG_MAX -
999ULL) / HZ)
...
jtimeout = (timeout < 0 || timeout >= EP_MAX_MSTIMEO) ?
MAX_SCHEDULE_TIMEOUT : (timeout * HZ + 999) / 1000;
I.e., with LONG_MAX of 2^31-1 and HZ=1000, any timeouts larger than 35
minutes are treated the same as -1 ("infinity").
Although I'm using 2.6.24, the code doesn't seem to have changed in 2.6.35.
I'm apparently not the first to have this problem
(http://www.provos.org/index.php?/archives/36-Libevent-1.4.4-stable-released
.html).
I suppose it is too late to change the interface to return an error when
setting too high a timeout and too tricky to fix epoll_wait to accept all
positive ints as timeouts.
Still, shouldn't the man page mention that there is a maximum allowable
value to the timeout and that it depends on whether you have a 64- or 32-bit
machine and what the timer frequency is?
/Fredrik Arnerup
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