From mboxrd@z Thu Jan 1 00:00:00 1970 Subject: Re: [PATCH] Use MPOL_PREFERRED for system default policy From: Lee Schermerhorn In-Reply-To: <1187122945.6281.92.camel@localhost> References: <1187120671.6281.67.camel@localhost> <1187122156.6281.77.camel@localhost> <1187122945.6281.92.camel@localhost> Content-Type: text/plain Date: Thu, 16 Aug 2007 10:23:41 -0400 Message-Id: <1187274221.5900.27.camel@localhost> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Christoph Lameter Cc: Andi Kleen , Andrew Morton , linux-mm , Eric Whitney List-ID: On Tue, 2007-08-14 at 16:22 -0400, Lee Schermerhorn wrote: > On Tue, 2007-08-14 at 16:09 -0400, Lee Schermerhorn wrote: > > On Tue, 2007-08-14 at 12:51 -0700, Christoph Lameter wrote: > > > On Tue, 14 Aug 2007, Lee Schermerhorn wrote: > > > > > > > Now, system default policy, except during boot, is "local > > > > allocation". By using the MPOL_PREFERRED mode with a negative > > > > value of preferred node for system default policy, MPOL_DEFAULT > > > > will never occur in the 'policy' member of a struct mempolicy. > > > > Thus, we can remove all checks for MPOL_DEFAULT when converting > > > > policy to a node id/zonelist in the allocation paths. > > > > > > Isnt it possible to set a task policy or VMA policy to MPOL_DEFAULT > > > through the API? For the VMA policy this would mean fall back to task > > > policy. Is that still possible? > > > > No. mpol_new() returns NULL if policy==MPOL_DEFAULT, so you end up just > > deleting any existing task policy and replacing it with a NULL pointer. > > This is pretty cool, I think. I have checked back, but Andi may have > ^^^^ haven't! > > done this from day 1. > > Christoph, Andi: Given that the mem policy does the right thing with this patch, can we merge it? I think it cleans up the mem policy concepts to have MPOL_DEFAULT mean "use default policy for this context/scope" rather than have an additional allocation behavior of its own. I'll update the man pages as well, once you've had a chance to review the current patches that Michael is holding. Lee -- 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