Messages in this thread | | | Date | Sun, 22 Sep 2002 00:48:25 +0000 | From | Pavel Machek <> | Subject | Re: [PATCH] de-xchg fork.c |
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Hi!
> Don't know who put this in for 2.5.38. > > I realize that using xchg() makes you 'leet. But doing an atomic op > where none is required is suboptimal and confusing.
Well, atomic op is also more expensive. i think ingo did this. Ingo, is patch below safe? It is faster *and* it works on 386. Pavel
> diff -urpN --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal linux-2.5.38/kernel/fork.c working-2.5.38-unxchg/kernel/fork.c > --- linux-2.5.38/kernel/fork.c 2002-09-21 13:55:19.000000000 +1000 > +++ working-2.5.38-unxchg/kernel/fork.c 2002-09-23 11:00:31.000000000 +1000 > @@ -64,11 +64,12 @@ void __put_task_struct(struct task_struc > } 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; > } > }
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