Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S936734AbZLQSqU (ORCPT ); Thu, 17 Dec 2009 13:46:20 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S936706AbZLQSqI (ORCPT ); Thu, 17 Dec 2009 13:46:08 -0500 Received: from one.firstfloor.org ([213.235.205.2]:33264 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S936694AbZLQSp5 (ORCPT ); Thu, 17 Dec 2009 13:45:57 -0500 To: Christoph Hellwig Cc: tytso@mit.edu, Linus Torvalds , Kyle McMartin , linux-parisc@vger.kernel.org, Linux Kernel Mailing List Subject: Re: [git patches] xfs and block fixes for virtually indexed arches From: Andi Kleen References: <20091216043618.GB9104@hera.kernel.org> <20091217132256.GO28962@bombadil.infradead.org> <20091217163036.GE2123@thunk.org> <20091217171025.GB10431@infradead.org> Date: Thu, 17 Dec 2009 19:45:55 +0100 In-Reply-To: <20091217171025.GB10431@infradead.org> (Christoph Hellwig's message of "Thu, 17 Dec 2009 12:10:25 -0500") Message-ID: <87zl5hsal8.fsf@basil.nowhere.org> User-Agent: Gnus/5.1008 (Gnus v5.10.8) Emacs/22.3 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1355 Lines: 32 Christoph Hellwig writes: > On Thu, Dec 17, 2009 at 11:30:36AM -0500, tytso@mit.edu wrote: >> That's because apparently the iSCSI and DMA blocks assume that they >> have Real Pages (tm) passed to block I/O requests, and apparently XFS >> ran into problems when sending vmalloc'ed pages. I don't know if this >> is a problem if we pass the bio layer addresses coming from the SLAB >> allocator, but oral tradition seems to indicate this is problematic, >> although no one has given me the full chapter and verse explanation >> about why this is so. > > Actually at least iscsi now has a workaround for that by checking for > PageSlab. Back when we deal with the XFS issue that check was only > available with debug options enabled. I tried to sort it out by > agreeing with the block and iscsi folks that either DRBD has the same workaround as well: if (disable_sendpage || (page_count(page) < 1) || PageSlab(page)) But it seems like a gross hack to me. Perhaps this should be passed as some sort of BIO attribute? -Andi -- ak@linux.intel.com -- Speaking for myself only. -- 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/