From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Fri, 9 Nov 2007 09:26:01 -0800 (PST) From: Christoph Lameter Subject: Re: [PATCH 6/6] Use one zonelist that is filtered by nodemask In-Reply-To: <1194628732.5296.14.camel@localhost> Message-ID: References: <20071109143226.23540.12907.sendpatchset@skynet.skynet.ie> <20071109143426.23540.44459.sendpatchset@skynet.skynet.ie> <20071109161455.GB32088@skynet.ie> <20071109164537.GG7507@us.ibm.com> <1194628732.5296.14.camel@localhost> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org Return-Path: To: Lee Schermerhorn Cc: Nishanth Aravamudan , Mel Gorman , akpm@linux-foundation.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, rientjes@google.com, kamezawa.hiroyu@jp.fujitsu.com List-ID: On Fri, 9 Nov 2007, Lee Schermerhorn wrote: > > On the other hand, if we call alloc_pages() with GFP_THISNODE set, there > > is no nid to base the allocation on, so we "fallback" to numa_node_id() > > [ almost like the nid had been specified as -1 ]. > > > > So I guess this is logical -- but I wonder, do we have any callers of > > alloc_pages(GFP_THISNODE) ? It seems like an odd thing to do, when > > alloc_pages_node() exists? > > I don't know if we have any current callers that do this, but absent any > documentation specifying otherwise, Mel's implementation matches what > I'd expect the behavior to be if I DID call alloc_pages with 'THISNODE. > However, we could specify that THISNODE is ignored in __alloc_pages() > and recommend the use of alloc_pages_node() passing numa_node_id() as > the nid parameter to achieve the behavior. This would eliminate the > check for 'THISNODE in __alloc_pages(). Just mask it off before calling > down to __alloc_pages_internal(). > > Does this make sense? I like consistency. If someone absolutely wants a local page then specifying GFP_THISNODE to __alloc_pages is okay. Leave as is I guess. What happens though if an MPOL_BIND policy is in effect? The node used must then be the nearest node from the policy mask.... -- 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