Kernel-Mode Parameter Table

The scheduler uses the kernel-mode parameter table, ts_kmdpris, to manage sleeping timesharing processes. A default version of ts_kmdpris is delivered with the system, in the /kernel/sched/TS_DPTBL loadable module, and is automatically built into the kernel as part of system configuration. See ts_dptbl(4) for more information.

The kernel assumes that it has at least 40 priorities in ts_kmdpris. It panics if it does not.

The kernel-mode parameter table is a one-dimensional array of global priorities from 60 through 99. If a process owns a critical resource, it is assigned a kernel priority so that it can release the resource as soon as possible. Critical resources are:

• An exclusive lock on a page

• A read lock on a readers/writer lock

Prior to SunOS 5.3, processes were assigned kernel priorities while they were asleep. This ensured that the resources they were waiting for were not paged out before they had a chance to execute again.

In order to do this after SunOS 5.3, processes return from sleep with the highest time-share priority (59).