From: Jens Axboe <axboe@suse.de>
To: "Chen, Kenneth W" <kenneth.w.chen@intel.com>
Cc: "'Andrew Morton'" <akpm@osdl.org>, linux-kernel@vger.kernel.org
Subject: Re: Cache queue_congestion_on/off_threshold
Date: Wed, 12 May 2004 16:22:59 +0200 [thread overview]
Message-ID: <20040512142259.GY14789@suse.de> (raw)
In-Reply-To: <200405120532.i4C5WCF25908@unix-os.sc.intel.com>
On Tue, May 11 2004, Chen, Kenneth W wrote:
> >>>> 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.
BTW, the barrier bit was buggy, but it could not make a difference since
the stock kernels + -mm doesn't use barriers. So you are right it's
wrong, but no impact on this test.
--
Jens Axboe
prev parent reply other threads:[~2004-05-12 14:23 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-05-05 22:12 Cache queue_congestion_on/off_threshold Chen, Kenneth W
2004-05-06 6:20 ` Jens Axboe
2004-05-06 6:34 ` Andrew Morton
2004-05-06 6:43 ` Jens Axboe
2004-05-06 20:30 ` Chen, Kenneth W
2004-05-07 3:02 ` Andrew Morton
2004-05-07 9:35 ` Jens Axboe
2004-05-06 20:29 ` Chen, Kenneth W
2004-05-07 9:39 ` Jens Axboe
2004-05-07 22:00 ` Chen, Kenneth W
2004-05-10 14:30 ` Jens Axboe
2004-05-10 14:43 ` Nick Piggin
2004-05-10 14:44 ` Jens Axboe
2004-05-11 3:22 ` Nick Piggin
2004-05-12 5:32 ` Chen, Kenneth W
2004-05-12 7:05 ` Jens Axboe
2004-05-12 13:48 ` Jens Axboe
2004-05-12 14:22 ` Jens Axboe [this message]
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