From: David Rientjes Subject: Re: [patch 1/5] mm: add nofail variants of kmalloc kcalloc and kzalloc Date: Wed, 25 Aug 2010 17:30:42 -0700 (PDT) Message-ID: References: <20100825115709.GD4453@thunk.org> <1282740516.2605.3644.camel@laptop> <1282740778.2605.3652.camel@laptop> <1282743090.2605.3696.camel@laptop> <1282769729.1975.96.camel@laptop> <1282771677.1975.138.camel@laptop> <20100826001901.GL4453@thunk.org> Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII To: "Ted Ts'o" , Peter Zijlstra , Jens Axboe , Andrew Morton , Neil Brown , Alasdair G Return-path: Received: from smtp-out.google.com ([216.239.44.51]:28303 "EHLO smtp-out.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752943Ab0HZAav (ORCPT ); Wed, 25 Aug 2010 20:30:51 -0400 In-Reply-To: <20100826001901.GL4453@thunk.org> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Wed, 25 Aug 2010, Ted Ts'o wrote: > > I'll repropose the patchset with __deprecated as you suggested. Thanks! > > And what Dave and I are saying is that we'll either need to do our on > loop to avoid the deprecation warning, or the use of the deprecated > function will probably be used forever... > We certainly hope that nobody will reimplement the same function without the __deprecated warning, especially for order < PAGE_ALLOC_COSTLY_ORDER where there's no looping at a higher level. So perhaps the best alternative is to implement the same _nofail() functions but do a WARN_ON(get_order(size) > PAGE_ALLOC_COSTLY_ORDER) instead? I think it's really sad that the caller can't know what the upper bounds of its memory requirement are ahead of time or at least be able to implement a memory freeing function when kmalloc() returns NULL.