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authorJake Burkholder <jake@FreeBSD.org>2001-02-12 00:20:08 +0000
committerJake Burkholder <jake@FreeBSD.org>2001-02-12 00:20:08 +0000
commitd5a08a6065a153f519dc5ada150c981d37f91345 (patch)
tree22feb65a2c5c3166f680bb7f0e4b1a6798b976c7 /sys/sys/runq.h
parent216a89d6a40093f3db32638d4b73d9b72816823c (diff)
downloadsrc-d5a08a6065a153f519dc5ada150c981d37f91345.tar.gz
src-d5a08a6065a153f519dc5ada150c981d37f91345.zip
Implement a unified run queue and adjust priority levels accordingly.
- All processes go into the same array of queues, with different scheduling classes using different portions of the array. This allows user processes to have their priorities propogated up into interrupt thread range if need be. - I chose 64 run queues as an arbitrary number that is greater than 32. We used to have 4 separate arrays of 32 queues each, so this may not be optimal. The new run queue code was written with this in mind; changing the number of run queues only requires changing constants in runq.h and adjusting the priority levels. - The new run queue code takes the run queue as a parameter. This is intended to be used to create per-cpu run queues. Implement wrappers for compatibility with the old interface which pass in the global run queue structure. - Group the priority level, user priority, native priority (before propogation) and the scheduling class into a struct priority. - Change any hard coded priority levels that I found to use symbolic constants (TTIPRI and TTOPRI). - Remove the curpriority global variable and use that of curproc. This was used to detect when a process' priority had lowered and it should yield. We now effectively yield on every interrupt. - Activate propogate_priority(). It should now have the desired effect without needing to also propogate the scheduling class. - Temporarily comment out the call to vm_page_zero_idle() in the idle loop. It interfered with propogate_priority() because the idle process needed to do a non-blocking acquire of Giant and then other processes would try to propogate their priority onto it. The idle process should not do anything except idle. vm_page_zero_idle() will return in the form of an idle priority kernel thread which is woken up at apprioriate times by the vm system. - Update struct kinfo_proc to the new priority interface. Deliberately change its size by adjusting the spare fields. It remained the same size, but the layout has changed, so userland processes that use it would parse the data incorrectly. The size constraint should really be changed to an arbitrary version number. Also add a debug.sizeof sysctl node for struct kinfo_proc.
Notes
Notes: svn path=/head/; revision=72376
Diffstat (limited to 'sys/sys/runq.h')
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diff --git a/sys/sys/runq.h b/sys/sys/runq.h
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+/*
+ * Copyright (c) 2001 Jake Burkholder <jake@FreeBSD.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * $FreeBSD$
+ */
+
+#ifndef _RUNQ_H_
+#define _RUNQ_H_
+
+/*
+ * Run queue parameters.
+ */
+
+#define RQ_NQS (64) /* Number of run queues. */
+#define RQ_PPQ (4) /* Priorities per queue. */
+
+#define RQB_LEN (2) /* Number of priority status words. */
+#define RQB_L2BPW (5) /* Log2(sizeof(rqb_word_t) * NBBY)). */
+#define RQB_BPW (1<<RQB_L2BPW) /* Bits in an rqb_word_t. */
+
+#define RQB_BIT(pri) (1 << ((pri) & (RQB_BPW - 1)))
+#define RQB_WORD(pri) ((pri) >> RQB_L2BPW)
+#define RQB_FFS(word) (ffs(word))
+
+/*
+ * Type of run queue status word.
+ */
+typedef u_int32_t rqb_word_t;
+
+/*
+ * Head of run queues.
+ */
+TAILQ_HEAD(rqhead, proc);
+
+/*
+ * Bit array which maintains the status of a run queue. When a queue is
+ * non-empty the bit corresponding to the queue number will be set.
+ */
+struct rqbits {
+ rqb_word_t rqb_bits[RQB_LEN];
+};
+
+/*
+ * Run queue structure. Contains an array of run queues on which processes
+ * are placed, and a structure to maintain the status of each queue.
+ */
+struct runq {
+ struct rqbits rq_status;
+ struct rqhead rq_queues[RQ_NQS];
+};
+
+void runq_add(struct runq *, struct proc *);
+int runq_check(struct runq *);
+struct proc *runq_choose(struct runq *);
+void runq_init(struct runq *);
+void runq_remove(struct runq *, struct proc *);
+
+#endif