From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Wed, 15 Oct 2008 11:29:32 -0700 (PDT) From: Linus Torvalds Subject: Re: [rfc] SLOB memory ordering issue In-Reply-To: <200810160512.28443.nickpiggin@yahoo.com.au> Message-ID: References: <200810160334.13082.nickpiggin@yahoo.com.au> <200810160445.28781.nickpiggin@yahoo.com.au> <200810160512.28443.nickpiggin@yahoo.com.au> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org Return-Path: To: Nick Piggin Cc: Matt Mackall , Pekka Enberg , linux-mm@kvack.org, linux-kernel@vger.kernel.org List-ID: On Thu, 16 Oct 2008, Nick Piggin wrote: > > When I said "I'd really hate to add a branch to the slab fastpath", it > wasn't a tacit acknowlegement that the barrier is the only way to go, > if it sounded that way. > > I meant: I'd *really* hate to add a branch to the slab fastpath :) Well, quite frankly, your choice of subject line and whole point of argument may have confused me. You started out - and continue to - make this sound like it's a SLAB/SLOB/SLUB issue. It's not. I agree there is quite likely memory ordering issues - possibly old ones, but quite possibly also ones that have just happened fairly recently as we've done more unlocked lookups - and all I've ever disagreed with is how you seem to have mixed this up with the allocator. And I still don't understand why you even _mention_ the slab fastpath. It seems totally immaterial. Linus -- 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