From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Fri, 10 Feb 2006 23:30:37 -0600 From: Marcelo Tosatti Subject: Re: [RFC] Removing page->flags Message-ID: <20060211053037.GA3331@dmt.cnet> References: <1139381183.22509.186.camel@localhost> <43E9DBE8.8020900@yahoo.com.au> <43EAC2CE.2010108@yahoo.com.au> <43EAD524.6020105@yahoo.com.au> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <43EAD524.6020105@yahoo.com.au> Sender: owner-linux-mm@kvack.org Return-Path: To: Nick Piggin Cc: Magnus Damm , Magnus Damm , linux-mm@kvack.org, Magnus Damm , Peter Zijlstra List-ID: On Thu, Feb 09, 2006 at 04:37:40PM +1100, Nick Piggin wrote: > Magnus Damm wrote: > > >But introducing a second page->flags is out of the question, and > >breaking out flags and placing a pointer to them in the node data > >structure will introduce more cache misses. So it is probably not > >worth it. > > > > Yep. Even then, you can't simply have a single non-atomic flags word, > unless _all_ flags are protected by the same lock. > > >> > >>It seems pretty unlikely that we'll get a pluggable replacement > >>policy in mainline any time soon though. > > > > > >So, do you think it is more likely that a ClockPro implementation will > >be accepted then? Or is Linux "doomed" to LRU forever? > > > > I think (hope) that Linux eventually (if slowly) moves toward the best > implementation available. I just don't think there will be sufficient > justification for a pluggable page reclaim infrastructure in the mainline > kernel. Hi Nick, There is no such thing as "best implementation available" given that page replacement policy is nothing more than a set of heuristics assuming certain characteristics of the underlying workload, and optimizing for that. Please refer to http://programming.kicks-ass.net/kernel-patches/clockpro-2/dev/2.6.16-rc2-1/ Peter's patchset implements a pluggable page reclaim infrastructure which is used by CLOCK-Pro and CART. -- 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