RE: Cache queue_congestion_on/off_threshold

[Chen, Kenneth W]

>>>> Jens Axboe wrote on Monday, May 10, 2004 7:30 AM
> > >
> > > Actually, with the good working batching we might get away with killing
> > > freereq completely. Have you tested that (if not, could you?)
> >
> > Sorry, I'm clueless on "good working batching".  If you could please give
> > me some pointers, I will definitely test it.
>
> Something like this.
>
> --- linux-2.6.6/drivers/block/ll_rw_blk.c~	2004-05-10 16:23:45.684726955 +0200
> +++ linux-2.6.6/drivers/block/ll_rw_blk.c	2004-05-10 16:29:04.333792268 +0200
> @@ -2138,8 +2138,8 @@
>
>  static int __make_request(request_queue_t *q, struct bio *bio)
>  {
> -	struct request *req, *freereq = NULL;
>  	int el_ret, rw, nr_sectors, cur_nr_sectors, barrier, ra;
> +	struct request *req;
>  	sector_t sector;
>
>
> [snip] ...

I'm still working on this.  With this patch, several processes stuck
in "D" state and never finish.  Suspect it's the barrier thing, it
jumps through blk_plug_device() and might goof up the queue afterwards.

- Ken


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