From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Sat, 26 Jul 2008 15:04:06 +0200 From: Nick Piggin Subject: Re: MMU notifiers review and some proposals Message-ID: <20080726130406.GA21820@wotan.suse.de> References: <20080724143949.GB12897@wotan.suse.de> <20080725214552.GB21150@duo.random> <20080726030810.GA18896@wotan.suse.de> <20080726113813.GD21150@duo.random> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20080726113813.GD21150@duo.random> Sender: owner-linux-mm@kvack.org Return-Path: To: Andrea Arcangeli Cc: Andrew Morton , Linus Torvalds , Linux Memory Management List , linux-arch@vger.kernel.org, steiner@sgi.com, cl@linux-foundation.org List-ID: On Sat, Jul 26, 2008 at 01:38:13PM +0200, Andrea Arcangeli wrote: > > 1) absolute minimal intrusion into the kernel common code, and > absolute minimum number of branches added to the kernel fast > paths. Kernel is faster than your "minimal" type of notifiers when > they're disarmed. BTW. is this really significant? Having one branch per pte I don't think is necessarily slower than 2 branches per unmap. The 2 branches will use more icache and more branch history. One branch even once per pte in the unmapping loop is going to remain hot in icache and branch history isn't it? -- 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