From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from d01relay04.pok.ibm.com (d01relay04.pok.ibm.com [9.56.227.236]) by e5.ny.us.ibm.com (8.13.8/8.13.8) with ESMTP id l5RNkbfn010565 for ; Wed, 27 Jun 2007 19:46:37 -0400 Received: from d01av04.pok.ibm.com (d01av04.pok.ibm.com [9.56.224.64]) by d01relay04.pok.ibm.com (8.13.8/8.13.8/NCO v8.3) with ESMTP id l5RNkZ9X557280 for ; Wed, 27 Jun 2007 19:46:37 -0400 Received: from d01av04.pok.ibm.com (loopback [127.0.0.1]) by d01av04.pok.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id l5RNkZIx026092 for ; Wed, 27 Jun 2007 19:46:35 -0400 Date: Wed, 27 Jun 2007 16:46:34 -0700 From: "Paul E. McKenney" Subject: Re: [PATCH/RFC 0/11] Shared Policy Overview Message-ID: <20070627234634.GI8604@linux.vnet.ibm.com> Reply-To: paulmck@linux.vnet.ibm.com References: <20070625195224.21210.89898.sendpatchset@localhost> <1182968078.4948.30.camel@localhost> <200706280001.16383.ak@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200706280001.16383.ak@suse.de> Sender: owner-linux-mm@kvack.org Return-Path: To: Andi Kleen Cc: Christoph Lameter , Lee Schermerhorn , linux-mm@kvack.org, akpm@linux-foundation.org, nacc@us.ibm.com List-ID: On Thu, Jun 28, 2007 at 12:01:16AM +0200, Andi Kleen wrote: > > > The zonelist from MPOL_BIND is passed to __alloc_pages. As a result the > > RCU lock must be held over the call into the page allocator with reclaim > > etc etc. Note that the zonelist is part of the policy structure. > > Yes I realized this at some point too. RCU doesn't work here because > __alloc_pages can sleep. Have to use the reference counts even though > it adds atomic operations. Any reason SRCU wouldn't work here? From a quick glance at the patch, it seems possible to me. Thanx, Paul > > I think one prerequisite to memory policy uses like this is work out how a > > memory policy can be handled by the page allocator in such a way that > > > > 1. The use is lightweight and does not impact performance. > > The current mempolicies are all lightweight and zero cost in the main > allocator path. > > The only outlier is still cpusets which does strange stuff, but you > can't blame mempolicies for that. > > -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