From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Wed, 20 Jun 2007 09:14:43 +0300 (EEST) From: Pekka J Enberg Subject: Re: [patch 05/26] Slab allocators: Cleanup zeroing allocations In-Reply-To: Message-ID: References: <20070618095838.238615343@sgi.com> <20070618095914.622685354@sgi.com> <20070619210010.GN11166@waste.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Christoph Lameter Cc: Matt Mackall , akpm@linux-foundation.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, suresh.b.siddha@intel.com List-ID: On Tue, 19 Jun 2007, Matt Mackall wrote: > > I worry a bit about adding another branch checking __GFP_ZERO in such > > a hot path for SLAB/SLUB. On Tue, 19 Jun 2007, Christoph Lameter wrote: > Its checking the gfpflags variable on the stack. In a recently touched > cachline. The variable could be in a register too but it's the _branch instruction_ that is bit worrisome especially for embedded devices (think slob). I haven't measured this, so consider this as pure speculation and hand-waving from my part. -- 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