Hi,
The patch below appears to fix a problem where a number of dead processes linger on the system. On a highly loaded system, dozens of processes were found stuck in do_exit(), calling thier very last schedule(), and then being lost forever. Processes that are PF_DEAD are cleaned up *after* the context switch, in a routine called finish_task_switch(task_t *prev). The "prev" gets the value returned by _switch() in entry.S, but this value comes from __switch_to (struct task_struct *prev, struct task_struct *new) { old_thread = ¤t->thread; ///XXX shouldn't this be prev, not current? last = _switch(old_thread, new_thread); return last; } The way I see it, "prev" and "current" are almost always going to be pointing at the same thing; however, if a "need resched" happens, or there's a pre-emept or some-such, then prev and current won't be the same; in which case, finish_task_switch() will end up cleaning up the old current, instead of prev. This will result in dead processes hanging around, which will never be scheduled again, and will never get a chance to have put_task_struct() called on them. This patch fixes this. Signed-off-by: Linas Vepstas <[EMAIL PROTECTED]> --- arch/ppc64/kernel/process.c.orig 2005-04-18 14:26:42.000000000 -0500 +++ arch/ppc64/kernel/process.c 2005-04-18 14:27:54.000000000 -0500 @@ -204,7 +204,7 @@ struct task_struct *__switch_to(struct t flush_tlb_pending(); new_thread = &new->thread; - old_thread = ¤t->thread; + old_thread = &prev->thread; local_irq_save(flags); last = _switch(old_thread, new_thread); - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/