From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Hellwig Subject: Re: [PATCH] virtio_blk: don't bounce highmem requests Date: Sat, 20 Jun 2009 20:32:15 +0200 Message-ID: <20090620183215.GA24936@lst.de> References: <20090619182022.GA10999@lst.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org To: rusty@rustcorp.com.au Return-path: Received: from verein.lst.de ([213.95.11.210]:58170 "EHLO verein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753727AbZFTScW (ORCPT ); Sat, 20 Jun 2009 14:32:22 -0400 Content-Disposition: inline In-Reply-To: <20090619182022.GA10999@lst.de> Sender: kvm-owner@vger.kernel.org List-ID: Looks like I sent a patch that doesn't actually compile because qui decided to apply those fixes to a different one. Here's the correc one: -- Subject: virtio_blk: don't bounce highmem requests From: Christoph Hellwig By default a block driver bounces highmem requests, but virtio-blk is perfectly fine with any request that fit into it's 64 bit addressing scheme, mapped in the kernel virtual space or not. Besides improving performance on highmem systems this also makes the reproducible oops in __bounce_end_io go away (but hiding the real cause). Signed-off-by: Christoph Hellwig Index: linux-2.6/drivers/block/virtio_blk.c =================================================================== --- linux-2.6.orig/drivers/block/virtio_blk.c 2009-06-20 20:11:44.769929544 +0200 +++ linux-2.6/drivers/block/virtio_blk.c 2009-06-20 20:20:29.661804686 +0200 @@ -360,6 +360,9 @@ static int __devinit virtblk_probe(struc blk_queue_max_phys_segments(vblk->disk->queue, vblk->sg_elems-2); blk_queue_max_hw_segments(vblk->disk->queue, vblk->sg_elems-2); + /* No need to bounce any requests */ + blk_queue_bounce_limit(vblk->disk->queue, BLK_BOUNCE_ANY); + /* No real sector limit. */ blk_queue_max_sectors(vblk->disk->queue, -1U);