From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nick Piggin Subject: Re: [dm-devel] Re: [PATCH resubmit] do_mount: reduce stack consumption Date: Tue, 08 Nov 2005 12:37:30 +1100 Message-ID: <4370015A.8010402@yahoo.com.au> References: <20051104105026.GA12476@osiris.boeblingen.de.ibm.com> <20051104084829.714c5dbb.akpm@osdl.org> <20051104212742.GC9222@osiris.ibm.com> <20051104235500.GE5368@stusta.de> <20051104160851.3a7463ff.akpm@osdl.org> <20051104173721.597bd223.akpm@osdl.org> <17260.17661.523593.420313@cse.unsw.edu.au> <17262.40176.342746.634262@cse.unsw.edu.au> <20051107153706.2f3c8b67.akpm@osdl.org> <436FF20D.8030200@yahoo.com.au> <17263.63845.556511.171582@cse.unsw.edu.au> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <17263.63845.556511.171582@cse.unsw.edu.au> Sender: linux-kernel-owner@vger.kernel.org To: Neil Brown Cc: Andrew Morton , dm-devel@redhat.com, heiko.carstens@de.ibm.com, linux-kernel@vger.kernel.org, aherrman@de.ibm.com, bunk@stusta.de, cplk@itee.uq.edu.au List-Id: dm-devel.ids Neil Brown wrote: > On Tuesday November 8, nickpiggin@yahoo.com.au wrote: >>Possibly it could go into struct io_context? >> > > > My quick reading of the code says that we could have to > allocate the struct right there in generic_make_request, and I don't > think we can be certain that such an allocation will succeed. > > Code that uses io_context can limp along if it doesn't exist. > The new generic_make_request needs this bio_list to be present > or it cannot do it's job. > You can ask for the io context without having a request. However, there is nothing like a mempool for them so code really should be able to limp along without them. I guess it would be silly to require such an allocation to succeed here, because the block layer is pretty free of OOM deadlocks. -- SUSE Labs, Novell Inc. Send instant messages to your online friends http://au.messenger.yahoo.com