From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Thu, 14 Jun 2007 07:24:55 -0700 (PDT) From: Christoph Lameter Subject: Re: [patch 2/3] Fix GFP_THISNODE behavior for memoryless nodes In-Reply-To: <1181830705.5410.13.camel@localhost> Message-ID: References: <20070612204843.491072749@sgi.com> <20070612205738.548677035@sgi.com> <1181769033.6148.116.camel@localhost> <1181830705.5410.13.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: akpm@linux-foundation.org, linux-mm@kvack.org, ak@suse.de, Nishanth Aravamudan List-ID: On Thu, 14 Jun 2007, Lee Schermerhorn wrote: > > That check is already done by __alloc_pages. > > You mean in get_page_from_freelist()? No, it only checks that the zone > under consideration is on the same node as the zone at the start of the > list. This can be off-node if the node is populated only at lower > zones; and the zonelists are in zone-order. See the later discussion. I did not see the use the nodes pgdat here that you only have in alloc_pages_node(). > > Ummm... Slub would need to consult node_memory_map instead I guess. > > Probably should check the node_memory_map to avoid attempting > allocations from completely memoryless nodes. However, it should still > be able to handle nulls from alloc_pages_nodes() because of the > scenarios discussed above. It is able to handle NULLs during usual operations but not during bootstrap. > Again, node_memory_map can't detect the "first zone in zonelist > off-node" situation. That's the one that alloc_pages_node() must guard > against. So, it can/should/must return NULL when attempting to > allocate from a higher zone that is off-node. I think GFP_THISNODE should not fail in that case. -- 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