On Mon, 23 Sep 2002, Rusty Russell wrote:
> - tsk = xchg(task_cache + cpu, tsk);
> + tsk = task_cache[cpu];
this was me - i forgot that this are per-CPU fields. (hey and i wrote the
original task_cache code so there's no excuse :-)
the attached patch (against BK-curr) fixes all xchg()'s and a preemption
bug.
Ingo
--- linux/kernel/fork.c.orig Mon Sep 23 20:28:36 2002
+++ linux/kernel/fork.c Mon Sep 23 20:30:02 2002
@@ -64,11 +64,12 @@
} else {
int cpu = smp_processor_id();
- tsk = xchg(task_cache + cpu, tsk);
+ tsk = task_cache[cpu];
if (tsk) {
free_thread_info(tsk->thread_info);
kmem_cache_free(task_struct_cachep,tsk);
}
+ task_cache[cpu] = current;
}
}
@@ -126,8 +127,11 @@
{
struct task_struct *tsk;
struct thread_info *ti;
+ int cpu = get_cpu();
- tsk = xchg(task_cache + smp_processor_id(), NULL);
+ tsk = task_cache[cpu];
+ task_cache[cpu] = NULL;
+ put_cpu();
if (!tsk) {
ti = alloc_thread_info();
if (!ti)
-
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This archive was generated by hypermail 2b29 : Mon Sep 23 2002 - 22:00:39 EST