From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail144.messagelabs.com (mail144.messagelabs.com [216.82.254.51]) by kanga.kvack.org (Postfix) with SMTP id BBFC48D0039 for ; Wed, 16 Mar 2011 18:36:34 -0400 (EDT) Date: 16 Mar 2011 18:36:31 -0400 Message-ID: <20110316223631.20091.qmail@science.horizon.com> From: "George Spelvin" Subject: Re: [PATCH 5/8] mm/slub: Factor out some common code. In-Reply-To: Sender: owner-linux-mm@kvack.org List-ID: To: linux@horizon.com, rientjes@google.com Cc: herbert@gondor.hengli.com.au, linux-kernel@vger.kernel.org, linux-mm@kvack.org, mpm@selenic.com, penberg@cs.helsinki.fi > Patches that you would like to propose but don't think are ready for merge > should have s/PATCH/RFC/ done on the subject line. You're right; I should have. I blame git-format-patch's defaults, but mea culpa. (Now I know about the --subject-prefix=RFC option!) > You deliberately created a helper function to take an unsigned int when > the actuals being passed in are all unsigned long to trigger a discussion > on why they are unsigned long? Er, no, I'm not that Machiavellian. I deliberately did it because it was obvious that the flags would always fit into an "unsigned", so I didn't need "unsigned long". (Actually, I owe you an apology; when writing that e-mail, I remember thinking "I should go back and clarify that statement", but forgot before hitting send.) > unsigned long uses the native word size of the architecture which can > generate more efficient code; we typically imply that flags have a limited > size by including leading zeros in their definition for 32-bit > compatibility: Um, can you name a (64-bit) architecture on which 32-bit is more expensive than 64-bit? On x86-64, it's potentially cheaper, and even the infamous Alpha 21064 has no penalty for 32-bit accesses. SPARC, MIPS, PPC, Itanium, what else? I don't know about z/ARchitecture, but given the emphasis on backward compatibility in IBM's mainframes, it seems hard to imagine. -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org