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| author | Greg Ungerer <gerg@snapgear.com> | 2005-06-03 11:35:20 +1000 |
|---|---|---|
| committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-06-03 08:16:17 -0700 |
| commit | b05a720b374ac6af05b2fd4c70bb2c61a9f461ca (patch) | |
| tree | 12de6955d12cd3c5660dd3411a50b125073688fa /arch | |
| parent | f4d340cf869b2b63e1043eed72aa2eab6fa2cb2c (diff) | |
| download | op-kernel-dev-b05a720b374ac6af05b2fd4c70bb2c61a9f461ca.zip op-kernel-dev-b05a720b374ac6af05b2fd4c70bb2c61a9f461ca.tar.gz | |
[PATCH] m68knommu: fix scheduling and race problems in idle loop
Re-work the m68knommu specific idle code according to suggestions
from Nick Piggin <nickpiggin@yahoo.com.au>.
A couple of rules that we need to follow:
1. Preempt should now disabled over idle routines. Should only be enabled
to call schedule() then disabled again.
3. When cpu_idle finds (need_resched() == 'true'), it should call schedule().
It should not call schedule() otherwise.
Also fix interrupt locking around the need_resched() and cpu stop state
so that there is no race condition.
Signed-off-by: Greg Ungerer <gerg@snapgear.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/m68knommu/kernel/process.c | 17 |
1 files changed, 12 insertions, 5 deletions
diff --git a/arch/m68knommu/kernel/process.c b/arch/m68knommu/kernel/process.c index 2b6c9d3..c4a33f2 100644 --- a/arch/m68knommu/kernel/process.c +++ b/arch/m68knommu/kernel/process.c @@ -45,11 +45,13 @@ asmlinkage void ret_from_fork(void); */ void default_idle(void) { - while(1) { - if (need_resched()) - __asm__("stop #0x2000" : : : "cc"); - schedule(); + local_irq_disable(); + while (!need_resched()) { + /* This stop will re-enable interrupts */ + __asm__("stop #0x2000" : : : "cc"); + local_irq_disable(); } + local_irq_enable(); } void (*idle)(void) = default_idle; @@ -63,7 +65,12 @@ void (*idle)(void) = default_idle; void cpu_idle(void) { /* endless idle loop with no priority at all */ - idle(); + while (1) { + idle(); + preempt_enable_no_resched(); + schedule(); + preempt_disable(); + } } void machine_restart(char * __unused) |
