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authorJeff Dike <jdike@addtoit.com>2007-10-16 04:27:25 -0400
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-10-16 12:43:08 -0400
commitd2753a6d199791a6abc75d9f657e3457fe61705f (patch)
treec4cda30f216d6c045ca2b83bee1fa6bc4dfc3de3 /arch/um/os-Linux/skas/process.c
parent791a644a8d73a9b95515f074afbb3caa0a9964fa (diff)
uml: tickless support
Enable tickless support. CONFIG_TICK_ONESHOT and CONFIG_NO_HZ are enabled. itimer_clockevent gets CLOCK_EVT_FEAT_ONESHOT and an implementation of .set_next_event. CONFIG_UML_REAL_TIME_CLOCK goes away because it only makes sense when there is a clock ticking away all the time. timer_handler now just calls do_IRQ once without trying to figure out how many ticks to emulate. The idle loop now needs to turn ticking on and off. Userspace ticks keep happening as usual. However, the userspace loop keep track of when the next wakeup should happen and suppresses process ticks until that happens. Signed-off-by: Jeff Dike <jdike@linux.intel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch/um/os-Linux/skas/process.c')
-rw-r--r--arch/um/os-Linux/skas/process.c27
1 files changed, 23 insertions, 4 deletions
diff --git a/arch/um/os-Linux/skas/process.c b/arch/um/os-Linux/skas/process.c
index 0036164bb0fb..3e64814e888e 100644
--- a/arch/um/os-Linux/skas/process.c
+++ b/arch/um/os-Linux/skas/process.c
@@ -287,10 +287,18 @@ int start_userspace(unsigned long stub_stack)
287 287
288void userspace(struct uml_pt_regs *regs) 288void userspace(struct uml_pt_regs *regs)
289{ 289{
290 struct itimerval timer;
291 unsigned long long nsecs, now;
290 int err, status, op, pid = userspace_pid[0]; 292 int err, status, op, pid = userspace_pid[0];
291 /* To prevent races if using_sysemu changes under us.*/ 293 /* To prevent races if using_sysemu changes under us.*/
292 int local_using_sysemu; 294 int local_using_sysemu;
293 295
296 if (getitimer(ITIMER_VIRTUAL, &timer))
297 printk("Failed to get itimer, errno = %d\n", errno);
298 nsecs = timer.it_value.tv_sec * BILLION +
299 timer.it_value.tv_usec * 1000;
300 nsecs += os_nsecs();
301
294 while (1) { 302 while (1) {
295 restore_registers(pid, regs); 303 restore_registers(pid, regs);
296 304
@@ -333,8 +341,18 @@ void userspace(struct uml_pt_regs *regs)
333 case SIGTRAP: 341 case SIGTRAP:
334 relay_signal(SIGTRAP, regs); 342 relay_signal(SIGTRAP, regs);
335 break; 343 break;
336 case SIGIO:
337 case SIGVTALRM: 344 case SIGVTALRM:
345 now = os_nsecs();
346 if(now < nsecs)
347 break;
348 block_signals();
349 (*sig_info[sig])(sig, regs);
350 unblock_signals();
351 nsecs = timer.it_value.tv_sec * BILLION +
352 timer.it_value.tv_usec * 1000;
353 nsecs += os_nsecs();
354 break;
355 case SIGIO:
338 case SIGILL: 356 case SIGILL:
339 case SIGBUS: 357 case SIGBUS:
340 case SIGFPE: 358 case SIGFPE:
@@ -378,6 +396,7 @@ __initcall(init_thread_regs);
378 396
379int copy_context_skas0(unsigned long new_stack, int pid) 397int copy_context_skas0(unsigned long new_stack, int pid)
380{ 398{
399 struct timeval tv = { .tv_sec = 0, .tv_usec = 1000000 / UM_HZ };
381 int err; 400 int err;
382 unsigned long current_stack = current_stub_stack(); 401 unsigned long current_stack = current_stub_stack();
383 struct stub_data *data = (struct stub_data *) current_stack; 402 struct stub_data *data = (struct stub_data *) current_stack;
@@ -392,9 +411,9 @@ int copy_context_skas0(unsigned long new_stack, int pid)
392 *data = ((struct stub_data) { .offset = MMAP_OFFSET(new_offset), 411 *data = ((struct stub_data) { .offset = MMAP_OFFSET(new_offset),
393 .fd = new_fd, 412 .fd = new_fd,
394 .timer = ((struct itimerval) 413 .timer = ((struct itimerval)
395 { { 0, 1000000 / UM_HZ }, 414 { .it_value = tv,
396 { 0, 1000000 / UM_HZ }}) 415 .it_interval = tv }) });
397 }); 416
398 err = ptrace_setregs(pid, thread_regs); 417 err = ptrace_setregs(pid, thread_regs);
399 if (err < 0) 418 if (err < 0)
400 panic("copy_context_skas0 : PTRACE_SETREGS failed, " 419 panic("copy_context_skas0 : PTRACE_SETREGS failed, "