Added a kernel worker thread for use when the kernel goes multithreaded.

sortix/Makefile

@@ -93,6 +93,7 @@ HEADERS:=$(shell find include -type f)
 OBJS=$(CPUOBJS) \
 kernel.o \
 interrupt.o \
+worker.o \
 time.o \
 log.o \
 utf8.o \

sortix/include/sortix/kernel/worker.h

@@ -0,0 +1,39 @@
+/*******************************************************************************
+
+	Copyright(C) Jonas 'Sortie' Termansen 2012.
+
+	This file is part of Sortix.
+
+	Sortix is free software: you can redistribute it and/or modify it under the
+	terms of the GNU General Public License as published by the Free Software
+	Foundation, either version 3 of the License, or (at your option) any later
+	version.
+
+	Sortix is distributed in the hope that it will be useful, but WITHOUT ANY
+	WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+	FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
+	details.
+
+	You should have received a copy of the GNU General Public License along with
+	Sortix. If not, see <http://www.gnu.org/licenses/>.
+
+	worker.h
+	Kernel worker thread.
+
+*******************************************************************************/
+
+#ifndef SORTIX_WORKER_H
+#define SORTIX_WORKER_H
+
+namespace Sortix {
+namespace Worker {
+
+void Init();
+void Schedule(void (*func)(void*), void* user = NULL);
+bool TrySchedule(void (*func)(void*), void* user = NULL);
+void Thread(void* user = NULL);
+
+} // namespace Worker
+} // namespace Sortix
+
+#endif

sortix/worker.cpp

@@ -0,0 +1,107 @@
+/*******************************************************************************
+
+	Copyright(C) Jonas 'Sortie' Termansen 2012.
+
+	This file is part of Sortix.
+
+	Sortix is free software: you can redistribute it and/or modify it under the
+	terms of the GNU General Public License as published by the Free Software
+	Foundation, either version 3 of the License, or (at your option) any later
+	version.
+
+	Sortix is distributed in the hope that it will be useful, but WITHOUT ANY
+	WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+	FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
+	details.
+
+	You should have received a copy of the GNU General Public License along with
+	Sortix. If not, see <http://www.gnu.org/licenses/>.
+
+	worker.cpp
+	Kernel worker thread.
+
+*******************************************************************************/
+
+#include <sortix/kernel/platform.h>
+#include <sortix/kernel/kthread.h>
+#include <sortix/kernel/worker.h>
+
+namespace Sortix {
+namespace Worker {
+
+struct Job
+{
+	void (*func)(void*);
+	void* user;
+};
+
+static kthread_mutex_t jobslock;
+static kthread_cond_t jobsready;
+static kthread_cond_t jobsfree;
+static size_t jobsused;
+static size_t jobsoff;
+static size_t jobslen;
+static Job* jobs;
+
+void Init()
+{
+	jobslock = KTHREAD_MUTEX_INITIALIZER;
+	jobsready = KTHREAD_COND_INITIALIZER;
+	jobsfree = KTHREAD_COND_INITIALIZER;
+	const size_t NUM_JOBS = 128UL;
+	jobslen = NUM_JOBS;
+	jobs = new Job[jobslen];
+	if ( !jobs )
+		Panic("Unable to allocate worker thread job queue");
+	jobsused = 0;
+	jobsoff = 0;
+}
+
+static bool _Schedule(void (*func)(void*), void* user, bool retry)
+{
+	ScopedLock lock(&jobslock);
+	if ( jobsused == jobslen && !retry )
+		return false;
+	while ( jobsused == jobslen )
+		kthread_cond_wait(&jobsfree, &jobslock);
+	if ( !jobsused )
+		kthread_cond_signal(&jobsready);
+	size_t index = (jobsoff + jobsused++) % jobslen;
+	jobs[index].func = func;
+	jobs[index].user = user;
+	return true;
+}
+
+void Schedule(void (*func)(void*), void* user)
+{
+	_Schedule(func, user, true);
+}
+
+bool TrySchedule(void (*func)(void*), void* user)
+{
+	return _Schedule(func, user, false);
+}
+
+static void PerformJob(Job* job)
+{
+	job->func(job->user);
+}
+
+void Thread(void* /*user*/)
+{
+	while ( true )
+	{
+		kthread_mutex_lock(&jobslock);
+		while ( !jobsused )
+			kthread_cond_wait(&jobsready, &jobslock);
+		Job job = jobs[jobsoff];
+		jobsoff = (jobsoff+1) % jobslen;
+		if ( jobsused-- == jobslen )
+			kthread_cond_signal(&jobsfree);
+		kthread_mutex_unlock(&jobslock);
+		PerformJob(&job);
+	}
+}
+
+} // namespace Worker
+} // namespace Sortix