Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261179AbVELGiH (ORCPT ); Thu, 12 May 2005 02:38:07 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261213AbVELGiH (ORCPT ); Thu, 12 May 2005 02:38:07 -0400 Received: from ns.virtualhost.dk ([195.184.98.160]:63980 "EHLO virtualhost.dk") by vger.kernel.org with ESMTP id S261179AbVELGiC (ORCPT ); Thu, 12 May 2005 02:38:02 -0400 Date: Thu, 12 May 2005 08:37:57 +0200 From: Jens Axboe To: Benjamin LaHaise Cc: linux-kernel@vger.kernel.org Subject: Re: reducing max segments expected to work? Message-ID: <20050512063757.GK23463@suse.de> References: <20050511214749.GA14072@kvack.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20050511214749.GA14072@kvack.org> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1740 Lines: 43 On Wed, May 11 2005, Benjamin LaHaise wrote: > Hello Jens et al, > > Is reducing the max number of segments in the block layer supposed to > work (as done in the patch below), or should i be sticking to mucking > with MAX_PHYS_SEGMENTS? I seem to get a kernel thatt cannot boot with > the below patch applied, and was wondering if you're aware of any > problems in this area. I'll probably post something more detailed > tomorrow after trying a few things. > > -ben > -- > "Time is what keeps everything from happening all at once." -- John Wheeler > > > diff -purN v2.6.12-rc4/include/linux/blkdev.h test-rc4/include/linux/blkdev.h > --- v2.6.12-rc4/include/linux/blkdev.h 2005-04-28 11:02:01.000000000 -0400 > +++ test-rc4/include/linux/blkdev.h 2005-05-11 17:06:10.000000000 -0400 > @@ -667,8 +667,8 @@ extern long blk_congestion_wait(int rw, > extern void blk_rq_bio_prep(request_queue_t *, struct request *, struct bio *); > extern int blkdev_issue_flush(struct block_device *, sector_t *); > > -#define MAX_PHYS_SEGMENTS 128 > -#define MAX_HW_SEGMENTS 128 > +#define MAX_PHYS_SEGMENTS 32 > +#define MAX_HW_SEGMENTS 32 > #define MAX_SECTORS 255 This doesn't really do what you would think it does - the defines should be called DEFAULT_PHYS_SEGMENTS etc, since they are just default values and do not denote any max-allowed-by-driver value. But it is strange why your system wont boot after applying the above. What happens (and what kind of storage)? -- Jens Axboe - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/