Re: PROBLEM: Bug in __pollwait() can cause select() and poll() to hang in 2.4.22-pre2 -- second try

[Ray Bryant <raybry@sgi.com>]

Rusty Russell wrote:

> Um, Ray?  2.4's yield also does:
> 
> 	void yield(void)
> 	{
> 		set_current_state(TASK_RUNNING);
> 		sys_sched_yield();
> 		schedule();
> 	}
> 
> So how did the below patch make any difference?
> 
> Now thoroughly confused,
> Rusty.
> 
> --- linux-2.4.22-pre2.orig/mm/page_alloc.c      Thu Nov 28 17:53:15 2002
> +++ linux-2.4.22-pre2/mm/page_alloc.c   Fri Jun 27 13:47:49 2003
> @@ -418,6 +418,7 @@
>                  return NULL;
> 
>          /* Yield for kswapd, and try again */
> +        set_current_state(TASK_RUNNING);
>          yield();
>          goto rebalance;
>   }
> 
> --
>   Anyone who quotes me in their sig is an idiot. -- Rusty Russell.
> 

Duh.  My fault.  I didn't see this in 2.4.22-pre2.  Some checking shows 
that it is also in 2.4.20.  How this didn't get into our SGI 2.4.20 tree 
is beyond me (this where we originally found this problem).  So there is 
no problem in 2.4.22-pre2.

Rusty -- thanks for your perseverence on this.

-- 
Best Regards,
Ray
-----------------------------------------------
                   Ray Bryant
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