Re: 2.5.2-pre1 dbench 32 hangs in vmstat "b" state

From: Jens Axboe (axboe@kernel.org)
Date: Fri Dec 21 2001 - 17:19:51 EST

On Fri, Dec 21 2001, rwhron@earthlink.net wrote:
> On Fri, Dec 21, 2001 at 06:01:56PM +0100, Jens Axboe wrote:
> > Thanks -- could you also try and do sysrq-t back traces when it seems
> > stuck?
> >
> > Does a non-highmem kernel run ok?
> >
> > --
> > Jens Axboe
>
> I recompiled with highmem turned off.
> # CONFIG_HIGHMEM4G is not set
> # CONFIG_HIGHMEM64G is not set
>
> I run a scripty that executes dbench 32, then dbench 128.

Ok, please try something for me. In drivers/block/elevator.c, comment
out this block:

        if (q->last_merge) {
                __rq = list_entry_rq(q->last_merge);
                BUG_ON(__rq->flags & REQ_STARTED);

                if ((ret = elv_try_merge(__rq, bio))) {
                        *req = __rq;
                        return ret;
                }
        }

(just #if 0 the entire thing) -- the one inside elevator_linus_merge()

Loop back highmem issue is different, I'll take a look at that later.
I'll be pretty unresponsive over christmas, though. 

-- 
Jens Axboe

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This archive was generated by hypermail 2b29 : Sun Dec 23 2001 - 21:00:26 EST