On Tue, Jun 14, 2016 at 08:05:49PM +0200, Thomas Gleixner wrote: > On Tue, 14 Jun 2016, Arjan van de Ven wrote: > > > evaluating a 120 hours timer ever 37 hours to see if it should fire... > > not too horrid. > > Well that thing is doing weird stuff anyway: > > swapper 0 [001] 1789995.305532: timer:timer_start: > timer=0xffff8800c8346920 function=death_by_timeout expires=4850639994 > [timeout=108000000] > ssh 3870 [001] 1790025.284704: timer:timer_cancel: > timer=0xffff8800c8346920 > ssh 3870 [001] 1790025.284707: timer:timer_start: > timer=0xffff8800c8346920 function=death_by_timeout expires=4742722493 > [timeout=75000] > swapper 0 [001] 1790025.330514: timer:timer_cancel: > timer=0xffff8800c8346920 > swapper 0 [001] 1790025.330515: timer:timer_start: > timer=0xffff8800c8346920 function=death_by_timeout expires=4850647504 > [timeout=108000000] > ssh 3870 [001] 1790055.307058: timer:timer_cancel: > timer=0xffff8800c8346920 > ssh 3870 [001] 1790055.307060: timer:timer_start: > timer=0xffff8800c8346920 function=death_by_timeout expires=4742730003 > [timeout=75000] > swapper 0 [001] 1790055.352146: timer:timer_cancel: > timer=0xffff8800c8346920 > > And that goes on forever. 2834 such sequences for this particular timer > instance in 4.5 hours. 90000 sequences total for all timers related to > death_by_timeout in 4.5 hours > > No idea what this is doing and why the heck it nees a 120 hour timeout ....
So it moves that timer on every packet for that TCP connection stream, provided the expiration is at least 1 second behind. If the stream hasn't had a packet in 5 days (see previous email), then the connection state is destroyed. Its been too long since I've read the TCP RFCs, but I can imagine changing this will upset people.
