On Tue, Feb 26, 2013 at 9:49 PM, Yasuaki Ishimatsu <isimatu.yasu...@jp.fujitsu.com> wrote: > 2013/02/27 14:11, Yinghai Lu wrote: >> >> On Tue, Feb 26, 2013 at 8:43 PM, Yasuaki Ishimatsu >> <isimatu.yasu...@jp.fujitsu.com> wrote: >>> >>> 2013/02/27 13:04, Yinghai Lu wrote: >>>> >>>> >>>> On Tue, Feb 26, 2013 at 7:38 PM, Yasuaki Ishimatsu >>>> <isimatu.yasu...@jp.fujitsu.com> wrote: >>>>> >>>>> >>>>> 2013/02/27 11:30, Yinghai Lu wrote: >>>>>> >>>>>> >>>>>> Do you mean you can not boot one socket system with 1G ram ? >>>>>> Assume socket 0 does not support hotplug, other 31 sockets support hot >>>>>> plug. >>>>>> >>>>>> So we could boot system only with socket0, and later one by one hot >>>>>> add other cpus. >>>>> >>>>> >>>>> >>>>> >>>>> In this case, system can boot. But other cpus with bunch of ram hot >>>>> plug may fails, since system does not have enough memory for cover >>>>> hot added memory. When hot adding memory device, kernel object for the >>>>> memory is allocated from 1G ram since hot added memory has not been >>>>> enabled. >>>>> >>>> >>>> yes, it may fail, if the one node memory need page table and vmemmap >>>> is more than 1g ... >>>> >>> > >>>> for hot add memory we need to >>>> 1. add another wrapper for init_memory_mapping, just like >>>> init_mem_mapping() for booting path. >>>> 2. we need make memblock more generic, so we can use it with hot add >>>> memory during runtime. >>>> 3. with that we can initialize page table for hot added node with ram. >>>> a. initial page table for 2M near node top is from node0 ( that does >>>> not support hot plug). >>>> b. then will use 2M for memory below node top... >>>> c. with that we will make sure page table stay on local node. >>>> alloc_low_pages need to be updated to support that. >>>> 4. need to make sure vmemmap on local node too. >>> >>> >>> >>> I think so too. By this, memory hot plug becomes more useful. > > > I agree with your idea. But I think above ideas is future work. > So at first we should use movable memory for memory hot plug. > After that, we will implement above ideas. > > >>> >>>> >>>> so hot-remove node will work too later. >>>> >>>> In the long run, we should make booting path and hot adding more >>>> similar and share at most code. >>>> That will make code get more test coverage. >> >> >> Tang, Yasuaki, Andrew, >> >> Please check if you are ok with attached reverting patch. > > > We will fix this problem with no objection. So please wait a while. > > And the problem occurs by "movablemem_map=srat" not > "movablemem_map=nn[KMG]@ss[KMG]" > At least, if you want to revert it, you should revert only > "movablemem_map=srat" part.
Those patches are tangled together. Also it looks funny to ask user to specify mem range in boot command line to enable mem hotplug. Thanks Yinghai -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/