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.Dd November 3, 2000
.Dt SLEEPQUEUE 9
.Os
.Sh NAME
.Nm endtsleep ,
.Nm sleepinit ,
.Nm unsleep
.Nd manage the queues of sleeping processes
.Sh SYNOPSIS
.In sys/param.h
.In sys/proc.h
.Ft void
.Fn endtsleep "void *arg"
.Ft void
.Fn sleepinit "void"
.Ft void
.Fn unsleep "struct thread *td"
.Sh DESCRIPTION
The sleep queues used by
.Xr msleep 9
and friends are stored in a hash array.
The address of the wait channel is used to generate an index into the array.
Each entry in the array is a queue of processes that are sleeping on wait
channels that hash to that index.
.Xr msleep 9
places processes into their appropriate queues directly.
To handle timeouts, the
.Fn endtsleep
function is registered as a
.Xr timeout 9 .
When the process is woken by either
.Fn wakeup
or
.Fn wakeup_one ,
the timeout is revoked via
.Xr untimeout 9 .
If the process is not awakened soon enough, then
.Fn endtsleep
is called with
.Fa arg
pointing to the
.Vt "struct proc"
of the process that timed out.
.Fn endtsleep
undoes the sleep and makes the process runnable if it is in the
.Dv SSLEEP
state.
The sleep queues and the hash array are protected internally by the
.Va sched_lock
mutex.
.Pp
.Fn unsleep
simply removes the thread
.Fa td
from its sleep queue.
.Pp
.Fn sleepinit
is called during system startup and initializes the scheduler quantum
.Pq Va sched_quantum
and the sleep queues.
.Sh SEE ALSO
.Xr msleep 9 ,
.Xr runqueue 9 ,
.Xr scheduler 9