From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail137.messagelabs.com (mail137.messagelabs.com [216.82.249.19]) by kanga.kvack.org (Postfix) with SMTP id BF7C96B004D for ; Tue, 2 Feb 2010 09:10:49 -0500 (EST) Date: Tue, 2 Feb 2010 15:10:36 +0100 From: Andrea Arcangeli Subject: Re: [RFP-V2 0/3] Make mmu_notifier_invalidate_range_start able to sleep. Message-ID: <20100202141036.GL4135@random.random> References: <20100202040145.555474000@alcatraz.americas.sgi.com> <20100202080947.GA28736@infradead.org> <20100202125943.GH4135@random.random> <20100202131341.GI4135@random.random> <20100202132919.GO6653@sgi.com> <20100202134047.GJ4135@random.random> <20100202135141.GH6616@sgi.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20100202135141.GH6616@sgi.com> Sender: owner-linux-mm@kvack.org To: Robin Holt Cc: Christoph Hellwig , Andrew Morton , Jack Steiner , linux-mm@kvack.org List-ID: On Tue, Feb 02, 2010 at 07:51:41AM -0600, Robin Holt wrote: > I don't see the change in API with this method either. The API change I'm referring to, is the reason that you had to patch virt/kvm/kvm_main.c and drivers/misc/sgi-gru/grutlbpurge.c to prevent compile failure. That isn't needed if we really make mmu notifier sleepable like my old patched did just fine. Except they slowed down the locking to achieve it... (the slowdown should be confined to config option) and you don't want that I guess. But if you didn't need to return -EINVAL I think your userland would also be safer. Only problem I can see is that you would then have trouble to convince distro to build with the slower locking and you basically are ok to break userland in truncate to be sure your module will work with default binary distro kernel. It's a tradeoff and I'm not against it but it has to be well documented that this is an hack to be practical on binary shipped kernels. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org