From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Fri, 25 Jul 2008 23:45:52 +0200 From: Andrea Arcangeli Subject: Re: MMU notifiers review and some proposals Message-ID: <20080725214552.GB21150@duo.random> References: <20080724143949.GB12897@wotan.suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20080724143949.GB12897@wotan.suse.de> Sender: owner-linux-mm@kvack.org Return-Path: To: Nick Piggin Cc: Andrew Morton , Linus Torvalds , Linux Memory Management List , linux-arch@vger.kernel.org, steiner@sgi.com, cl@linux-foundation.org List-ID: Hi Nick, On Thu, Jul 24, 2008 at 04:39:49PM +0200, Nick Piggin wrote: > I think everybody is hoping to have a workable mmu notifier scheme > merged in 2.6.27 (myself included). However I do have some concerns Just to be clear, I'm waiting mmu notifiers to showup on Linus's tree before commenting this as it was all partly covered in the past discussions anyway, so there's nothing really urgent or new here (at least for me ;). It's a tradeoff, you pointed out the positive sides and negative point of both approaches, and depending which kind of the trade you're interested about, you'll prefer one or the other approach. Your preference is the exact opposite of what SGI liked and what we liked. But all works for us, and all works for GRU (though -mm is faster for the fast path), but only -mm can be easily later extended for XPMEM/IB if they ever decide to schedule in the mmu notifier methods in the future (which may never happen and it's unrelated to the current patches that don't contemplate sleeping at all and it's pure luck they can be trivially extended to provide for it). As your patch shown the changes are fairly small anyway if we later decide to change in 2.6.28-rc, in the meantime current code in -mm was heavily tested and all code including kvm and gru has been tested only with this, and this combined with the fact -mm guarantees the fastest fast path, I hope we leave any discussion to the 2.6.28-rc merge window, now it's time to go productive finally! -- 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