b4cf88a04f
- cotributed by Bjorn Swift - In this first phase, scheduling is moved from the kernel to the PM server. The next steps are to a) moving scheduling to its own server and b) include useful information in the "out of quantum" message, so that the scheduler can make use of this information. - The kernel process table now keeps record of who is responsible for scheduling each process (p_scheduler). When this pointer is NULL, the process will be scheduled by the kernel. If such a process runs out of quantum, the kernel will simply renew its quantum an requeue it. - When PM loads, it will take over scheduling of all running processes, except system processes, using sys_schedctl(). Essentially, this only results in taking over init. As children inherit a scheduler from their parent, user space programs forked by init will inherit PM (for now) as their scheduler. - Once a process has been assigned a scheduler, and runs out of quantum, its RTS_NO_QUANTUM flag will be set and the process dequeued. The kernel will send a message to the scheduler, on the process' behalf, informing the scheduler that it has run out of quantum. The scheduler can take what ever action it pleases, based on its policy, and then reschedule the process using the sys_schedule() system call. - Balance queues does not work as before. While the old in-kernel function used to renew the quantum of processes in the highest priority run queue, the user-space implementation only acts on processes that have been bumped down to a lower priority queue. This approach reacts slower to changes than the old one, but saves us sending a sys_schedule message for each process every time we balance the queues. Currently, when processes are moved up a priority queue, their quantum is also renewed, but this can be fiddled with. - do_nice has been removed from kernel. PM answers to get- and setpriority calls, updates it's own nice variable as well as the max_run_queue. This will be refactored once scheduling is moved to a separate server. We will probably have PM update it's local nice value and then send a message to whoever is scheduling the process. - changes to fix an issue in do_fork() where processes could run out of quantum but bypassing the code path that handles it correctly. The future plan is to remove the policy from do_fork() and implement it in userspace too.
66 lines
3.2 KiB
C
66 lines
3.2 KiB
C
#ifndef CONFIG_H
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#define CONFIG_H
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/* This file defines the kernel configuration. It allows to set sizes of some
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* kernel buffers and to enable or disable debugging code, timing features,
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* and individual kernel calls.
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*
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* Changes:
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* Jul 11, 2005 Created. (Jorrit N. Herder)
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*/
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/* In embedded and sensor applications, not all the kernel calls may be
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* needed. In this section you can specify which kernel calls are needed
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* and which are not. The code for unneeded kernel calls is not included in
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* the system binary, making it smaller. If you are not sure, it is best
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* to keep all kernel calls enabled.
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*/
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#define USE_FORK 1 /* fork a new process */
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#define USE_NEWMAP 1 /* set a new memory map */
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#define USE_EXEC 1 /* update process after execute */
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#define USE_CLEAR 1 /* clean up after process exit */
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#define USE_EXIT 1 /* a system process wants to exit */
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#define USE_TRACE 1 /* process information and tracing */
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#define USE_GETKSIG 1 /* retrieve pending kernel signals */
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#define USE_ENDKSIG 1 /* finish pending kernel signals */
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#define USE_KILL 1 /* send a signal to a process */
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#define USE_SIGSEND 1 /* send POSIX-style signal */
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#define USE_SIGRETURN 1 /* sys_sigreturn(proc_nr, ctxt_ptr, flags) */
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#define USE_ABORT 1 /* shut down MINIX */
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#define USE_GETINFO 1 /* retrieve a copy of kernel data */
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#define USE_TIMES 1 /* get process and system time info */
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#define USE_SETALARM 1 /* schedule a synchronous alarm */
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#define USE_VTIMER 1 /* set or retrieve a process-virtual timer */
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#define USE_DEVIO 1 /* read or write a single I/O port */
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#define USE_VDEVIO 1 /* process vector with I/O requests */
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#define USE_SDEVIO 1 /* perform I/O request on a buffer */
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#define USE_IRQCTL 1 /* set an interrupt policy */
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#define USE_SEGCTL 1 /* set up a remote segment */
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#define USE_PRIVCTL 1 /* system privileges control */
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#define USE_UMAP 1 /* map virtual to physical address */
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#define USE_VIRCOPY 1 /* copy using virtual addressing */
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#define USE_PHYSCOPY 1 /* copy using physical addressing */
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#define USE_MEMSET 1 /* write char to a given memory area */
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#define USE_RUNCTL 1 /* control stop flags of a process */
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#define USE_UPDATE 1 /* update a process into another */
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#define USE_MCONTEXT 1 /* enable getting and setting of mach context*/
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/* Length of program names stored in the process table. This is only used
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* for the debugging dumps that can be generated with the IS server. The PM
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* server keeps its own copy of the program name.
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*/
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#define P_NAME_LEN 8
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/* This section contains defines for valuable system resources that are used
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* by device drivers. The number of elements of the vectors is determined by
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* the maximum needed by any given driver. The number of interrupt hooks may
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* be incremented on systems with many device drivers.
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*/
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#define NR_IRQ_HOOKS 16 /* number of interrupt hooks */
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#define VDEVIO_BUF_SIZE 64 /* max elements per VDEVIO request */
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/* How many bytes for the kernel stack. Space allocated in mpx.s. */
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#define K_STACK_BYTES 1024
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#endif /* CONFIG_H */
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