Hey, On Tue, Aug 13, 2013 at 01:01:09AM +0800, Tang Chen wrote: > Sorry for the misunderstanding. > > I was trying to answer your question: "Why can't the kenrel allocate > hotpluggable memory opportunistic ?". I've used the wrong word, I was meaning best-effort, which is the only thing we can do anyway given that we have no control over where the kernel image is linked in relation to NUMA nodes. > If the kernel has any opportunity to allocate hotpluggable memory in > SRAT, then the kernel should tell users which memory is hotpluggable. > > But in what way ? I think node is the best for now. But a node could > have a lot of memory. If the kernel uses only a little memory, we will > lose the whole movable node, which I don't want to do. > > So, I don't want to allow the kenrel allocating hotpluggable memory > opportunistic. What I was saying was that the kernel should try !hotpluggable memory first then fall back to hotpluggable memory instead of failing boot as nothing really is worse than failing to boot. > >Short of being able to remap memory under the kernel, I don't think > >this can be very generic and as a compromise trying to keep as many > >hotpluggable nodes as possible doesn't sound too bad. > > I think making one of the node hotpluggable is better. But OK, it is > no big deal. There won't be such machine in reality, I think. :) Hmmm... but allocating close to kernel image will keep the number of nodes which are made un-removeable via permanent allocation to minimum. In most configurations that I can recall, I don't think we'd lose anything really and the code will be much simpler and generic. It seems like a good trade-off to me given that we need to report which nodes are hot unpluggable no matter what. Thanks. -- tejun -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>