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| author |   Ingo Molnar <mingo@elte.hu> | 2005-06-28 16:40:42 +0200 |
|---|---|---|
| committer |   Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-06-28 14:56:51 -0700 |
| commit | f340c0d1a3f40fdcba69cd291530a4debc58748f (patch) | |
| tree | 22fca5983aff6ce2aa7d4ede0b031666dfe1f28d | |
| parent | [PATCH] ll_rw_blk: prevent huge request allocations (diff) | |
| download | linux-dev-f340c0d1a3f40fdcba69cd291530a4debc58748f.tar.xz linux-dev-f340c0d1a3f40fdcba69cd291530a4debc58748f.zip | |
[PATCH] Tweak idle thread setup semantics
This patch tweaks idle thread setup semantics a bit: instead of setting
NEED_RESCHED in init_idle(), we do an explicit schedule() before calling
into cpu_idle().
This patch, while having no negative side-effects, enables wider use of
cond_resched()s. (which might happen in the stock kernel too, but it's
particulary important for voluntary-preempt)
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
| -rw-r--r-- | init/main.c | 7 | ||||
| -rw-r--r-- | kernel/sched.c | 9 |
2 files changed, 15 insertions, 1 deletions
diff --git a/init/main.c b/init/main.c index d324801729ba..b5e421e39ede 100644 --- a/init/main.c +++ b/init/main.c @@ -383,6 +383,13 @@ static void noinline rest_init(void) numa_default_policy(); unlock_kernel(); preempt_enable_no_resched(); + + /* + * The boot idle thread must execute schedule() + * at least one to get things moving: + */ + schedule(); + cpu_idle(); } diff --git a/kernel/sched.c b/kernel/sched.c index e2b0d3e4dd06..5f2182d42241 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -4166,6 +4166,14 @@ void show_state(void) read_unlock(&tasklist_lock); } +/** + * init_idle - set up an idle thread for a given CPU + * @idle: task in question + * @cpu: cpu the idle task belongs to + * + * NOTE: this function does not set the idle thread's NEED_RESCHED + * flag, to make booting more robust. + */ void __devinit init_idle(task_t *idle, int cpu) { runqueue_t *rq = cpu_rq(cpu); @@ -4183,7 +4191,6 @@ void __devinit init_idle(task_t *idle, int cpu) #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW) idle->oncpu = 1; #endif - set_tsk_need_resched(idle); spin_unlock_irqrestore(&rq->lock, flags); /* Set the preempt count _outside_ the spinlocks! */ |