Messages in this thread | | | Date | Fri, 21 May 2010 16:22:19 +0800 | From | minskey guo <> | Subject | Re: [PATCH] online CPU before memory failed in pcpu_alloc_pages() |
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>>>> --- a/mm/percpu.c >>>> +++ b/mm/percpu.c >>>> @@ -714,13 +714,29 @@ static int pcpu_alloc_pages(struct pcpu_chunk *chunk, >>> >>> In linux-next, Tejun has gone and moved pcpu_alloc_pages() into the new >>> mm/percpu-vm.c. So either >> >> This has gone into Linus' tree today ... >> > > Hmm, a comment here. > > Recently, Lee Schermerhorn developed > > numa-introduce-numa_mem_id-effective-local-memory-node-id-fix2.patch > > Then, you can use cpu_to_mem() instead of cpu_to_node() to find the > nearest available node. > I don't check cpu_to_mem() is synchronized with NUMA hotplug but > using cpu_to_mem() rather than adding > = > > + if ((nid == -1) || > + !(node_zonelist(nid, GFP_KERNEL)->_zonerefs->zone)) > + nid = numa_node_id(); > + > == > > is better.
Yes. I can use cpu_to_mem(). only some little difference during CPU online: 1st cpu within memoryless node gets memory from current node or the node to which the cpu0 belongs,
But I have a question about the patch:
numa-slab-use-numa_mem_id-for-slab-local-memory-node.patch,
@@ -2968,9 +2991,23 @@ static int __build_all_zonelists(void *d ...
- for_each_possible_cpu(cpu) + for_each_possible_cpu(cpu) { setup_pageset(&per_cpu(boot_pageset, cpu), 0); ...
+#ifdef CONFIG_HAVE_MEMORYLESS_NODES + if (cpu_online(cpu)) + cpu_to_mem(cpu) = local_memory_node(cpu_to_node(cpu)); +#endif
Look at the last two lines, suppose that memory is onlined before CPUs, where will cpu_to_mem(cpu) be set to the right nodeid for the last onlined cpu ? Does that CPU always get memory from the node including cpu0 for slab allocator where cpu_to_mem() is used ?
thanks, -minskey
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