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| author | Nick Piggin <nickpiggin@yahoo.com.au> | 2005-11-09 06:39:01 +0100 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2005-11-09 16:56:33 +0100 |
| commit | 5bfb5d690f36d316a5f3b4f7775fda996faa6b12 (patch) | |
| tree | ea53f15293d1ddb49c316eb65df85e939a4f6e5e /arch/v850 | |
| parent | [PATCH] sched: consider migration thread with smp nice (diff) | |
| download | linux-5bfb5d690f36d316a5f3b4f7775fda996faa6b12.tar.xz linux-5bfb5d690f36d316a5f3b4f7775fda996faa6b12.zip | |
[PATCH] sched: disable preempt in idle tasks
Run idle threads with preempt disabled.
Also corrected a bugs in arm26's cpu_idle (make it actually call schedule()).
How did it ever work before?
Might fix the CPU hotplugging hang which Nigel Cunningham noted.
We think the bug hits if the idle thread is preempted after checking
need_resched() and before going to sleep, then the CPU offlined.
After calling stop_machine_run, the CPU eventually returns from preemption and
into the idle thread and goes to sleep. The CPU will continue executing
previous idle and have no chance to call play_dead.
By disabling preemption until we are ready to explicitly schedule, this bug is
fixed and the idle threads generally become more robust.
From: alexs <ashepard@u.washington.edu>
PPC build fix
From: Yoichi Yuasa <yuasa@hh.iij4u.or.jp>
MIPS build fix
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Yoichi Yuasa <yuasa@hh.iij4u.or.jp>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'arch/v850')
| -rw-r--r-- | arch/v850/kernel/process.c | 16 |
1 files changed, 10 insertions, 6 deletions
diff --git a/arch/v850/kernel/process.c b/arch/v850/kernel/process.c index 9c708c32c1f0..39cf247cdae4 100644 --- a/arch/v850/kernel/process.c +++ b/arch/v850/kernel/process.c @@ -36,11 +36,8 @@ extern void ret_from_fork (void); /* The idle loop. */ void default_idle (void) { - while (1) { - while (! need_resched ()) - asm ("halt; nop; nop; nop; nop; nop" ::: "cc"); - schedule (); - } + while (! need_resched ()) + asm ("halt; nop; nop; nop; nop; nop" ::: "cc"); } void (*idle)(void) = default_idle; @@ -54,7 +51,14 @@ void (*idle)(void) = default_idle; void cpu_idle (void) { /* endless idle loop with no priority at all */ - (*idle) (); + while (1) { + while (!need_resched()) + (*idle) (); + + preempt_enable_no_resched(); + schedule(); + preempt_disable(); + } } /* |