Rearrange proc.h and proc.c to get our action-packed spreads back (mostly). They also make sense in this order, so it's not just for page layout.
This commit is contained in:
Austin Clements
parent
dd3ecd42cd
commit
d8828817d7
3 changed files with 126 additions and 120 deletions
172
proc.c
172
proc.c
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@ -193,6 +193,92 @@ fork(void)
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return pid;
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}
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// Exit the current process. Does not return.
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// An exited process remains in the zombie state
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// until its parent calls wait() to find out it exited.
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void
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exit(void)
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{
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struct proc *p;
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int fd;
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if(proc == initproc)
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panic("init exiting");
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// Close all open files.
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for(fd = 0; fd < NOFILE; fd++){
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if(proc->ofile[fd]){
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fileclose(proc->ofile[fd]);
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proc->ofile[fd] = 0;
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}
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}
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iput(proc->cwd);
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proc->cwd = 0;
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acquire(&ptable.lock);
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// Parent might be sleeping in wait().
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wakeup1(proc->parent);
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// Pass abandoned children to init.
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for(p = ptable.proc; p < &ptable.proc[NPROC]; p++){
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if(p->parent == proc){
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p->parent = initproc;
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if(p->state == ZOMBIE)
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wakeup1(initproc);
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}
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}
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// Jump into the scheduler, never to return.
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proc->state = ZOMBIE;
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sched();
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panic("zombie exit");
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}
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// Wait for a child process to exit and return its pid.
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// Return -1 if this process has no children.
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int
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wait(void)
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{
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struct proc *p;
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int havekids, pid;
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acquire(&ptable.lock);
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for(;;){
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// Scan through table looking for zombie children.
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havekids = 0;
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for(p = ptable.proc; p < &ptable.proc[NPROC]; p++){
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if(p->parent != proc)
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continue;
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havekids = 1;
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if(p->state == ZOMBIE){
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// Found one.
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pid = p->pid;
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kfree(p->kstack);
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p->kstack = 0;
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freevm(p->pgdir);
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p->state = UNUSED;
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p->pid = 0;
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p->parent = 0;
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p->name[0] = 0;
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p->killed = 0;
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release(&ptable.lock);
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return pid;
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}
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}
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// No point waiting if we don't have any children.
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if(!havekids || proc->killed){
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release(&ptable.lock);
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return -1;
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}
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// Wait for children to exit. (See wakeup1 call in proc_exit.)
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sleep(proc, &ptable.lock); //DOC: wait-sleep
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}
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}
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//PAGEBREAK: 42
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// Per-CPU process scheduler.
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// Each CPU calls scheduler() after setting itself up.
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@ -357,89 +443,3 @@ kill(int pid)
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return -1;
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}
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// Exit the current process. Does not return.
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// An exited process remains in the zombie state
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// until its parent calls wait() to find out it exited.
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void
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exit(void)
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{
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struct proc *p;
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int fd;
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if(proc == initproc)
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panic("init exiting");
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// Close all open files.
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for(fd = 0; fd < NOFILE; fd++){
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if(proc->ofile[fd]){
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fileclose(proc->ofile[fd]);
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proc->ofile[fd] = 0;
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}
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}
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iput(proc->cwd);
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proc->cwd = 0;
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acquire(&ptable.lock);
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// Parent might be sleeping in wait().
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wakeup1(proc->parent);
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// Pass abandoned children to init.
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for(p = ptable.proc; p < &ptable.proc[NPROC]; p++){
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if(p->parent == proc){
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p->parent = initproc;
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if(p->state == ZOMBIE)
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wakeup1(initproc);
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}
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}
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// Jump into the scheduler, never to return.
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proc->state = ZOMBIE;
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sched();
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panic("zombie exit");
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}
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// Wait for a child process to exit and return its pid.
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// Return -1 if this process has no children.
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int
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wait(void)
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{
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struct proc *p;
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int havekids, pid;
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acquire(&ptable.lock);
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for(;;){
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// Scan through table looking for zombie children.
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havekids = 0;
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for(p = ptable.proc; p < &ptable.proc[NPROC]; p++){
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if(p->parent != proc)
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continue;
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havekids = 1;
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if(p->state == ZOMBIE){
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// Found one.
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pid = p->pid;
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kfree(p->kstack);
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p->kstack = 0;
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freevm(p->pgdir);
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p->state = UNUSED;
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p->pid = 0;
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p->parent = 0;
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p->name[0] = 0;
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p->killed = 0;
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release(&ptable.lock);
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return pid;
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}
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}
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// No point waiting if we don't have any children.
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if(!havekids || proc->killed){
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release(&ptable.lock);
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return -1;
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}
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// Wait for children to exit. (See wakeup1 call in proc_exit.)
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sleep(proc, &ptable.lock); //DOC: wait-sleep
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}
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}
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59
proc.h
59
proc.h
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@ -8,6 +8,36 @@
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#define SEG_TSS 6 // this process's task state
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#define NSEGS 7
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// Per-CPU state
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struct cpu {
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uchar id; // Local APIC ID; index into cpus[] below
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struct context *scheduler; // Switch here to enter scheduler
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struct taskstate ts; // Used by x86 to find stack for interrupt
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struct segdesc gdt[NSEGS]; // x86 global descriptor table
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volatile uint booted; // Has the CPU started?
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int ncli; // Depth of pushcli nesting.
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int intena; // Were interrupts enabled before pushcli?
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// Cpu-local storage variables; see below
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struct cpu *cpu;
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struct proc *proc;
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};
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extern struct cpu cpus[NCPU];
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extern int ncpu;
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// Per-CPU variables, holding pointers to the
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// current cpu and to the current process.
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// The asm suffix tells gcc to use "%gs:0" to refer to cpu
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// and "%gs:4" to refer to proc. ksegment sets up the
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// %gs segment register so that %gs refers to the memory
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// holding those two variables in the local cpu's struct cpu.
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// This is similar to how thread-local variables are implemented
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// in thread libraries such as Linux pthreads.
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extern struct cpu *cpu asm("%gs:0"); // This cpu.
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extern struct proc *proc asm("%gs:4"); // Current proc on this cpu.
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//PAGEBREAK: 17
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// Saved registers for kernel context switches.
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// Don't need to save all the segment registers (%cs, etc),
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// because they are constant across kernel contexts.
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@ -50,32 +80,3 @@ struct proc {
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// original data and bss
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// fixed-size stack
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// expandable heap
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// Per-CPU state
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struct cpu {
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uchar id; // Local APIC ID; index into cpus[] below
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struct context *scheduler; // Switch here to enter scheduler
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struct taskstate ts; // Used by x86 to find stack for interrupt
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struct segdesc gdt[NSEGS]; // x86 global descriptor table
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volatile uint booted; // Has the CPU started?
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int ncli; // Depth of pushcli nesting.
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int intena; // Were interrupts enabled before pushcli?
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// Cpu-local storage variables; see below
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struct cpu *cpu;
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struct proc *proc;
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};
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extern struct cpu cpus[NCPU];
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extern int ncpu;
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// Per-CPU variables, holding pointers to the
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// current cpu and to the current process.
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// The asm suffix tells gcc to use "%gs:0" to refer to cpu
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// and "%gs:4" to refer to proc. ksegment sets up the
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// %gs segment register so that %gs refers to the memory
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// holding those two variables in the local cpu's struct cpu.
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// This is similar to how thread-local variables are implemented
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// in thread libraries such as Linux pthreads.
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extern struct cpu *cpu asm("%gs:0"); // This cpu.
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extern struct proc *proc asm("%gs:4"); // Current proc on this cpu.
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15
runoff.spec
15
runoff.spec
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@ -20,22 +20,27 @@ sheet1: left
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even: bootasm.S # mild preference
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even: bootother.S # mild preference
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even: bootmain.S # mild preference
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even: bootmain.c # mild preference
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even: main.c
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# mp.c don't care at all
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# even: initcode.S
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# odd: init.c
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# spinlock.h either
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left: spinlock.c # mild preference
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even: proc.h # mild preference
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left: spinlock.h # mild preference
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even: spinlock.h # mild preference
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# This gets struct proc and allocproc on the same spread
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right: proc.h
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odd: proc.h
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# goal is to have two action-packed 2-page spreads,
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# one with
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# allocproc userinit growproc fork
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# userinit growproc fork exit wait
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# and another with
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# scheduler sched yield forkret sleep wakeup1 wakeup
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right: proc.c # VERY important
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left: proc.c # VERY important
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odd: proc.c # VERY important
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# setjmp.S either
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# vm.c either
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