From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Mon, 22 Aug 2005 17:43:00 +0200 From: Andi Kleen Subject: Re: [PATCH] Use deltas to replace atomic inc Message-ID: <20050822154300.GA29976@wotan.suse.de> References: <20050820005843.21ba4d9b.akpm@osdl.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org Return-Path: To: Christoph Lameter Cc: Hugh Dickins , Linus Torvalds , Andrew Morton , nickpiggin@yahoo.com.au, linux-mm@kvack.org List-ID: On Mon, Aug 22, 2005 at 08:24:50AM -0700, Christoph Lameter wrote: > On Mon, 22 Aug 2005, Hugh Dickins wrote: > > > (Your deltas seem sensible, but hard to place the reaccumulation: > > I worry that you may be taking page_table_lock more just for that.) > > The page_table_lock is taken using a spin_trylock. Its skipped if > contended. Hmm - doesn't try lock cause a cache line bounce on the bus too? I think it does. That would mean its latency is not much better than a real spinlock (assuming it doesn't have to spin) -Andi -- 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