On 2012/11/27 13:43, Tang Chen wrote: > On 11/27/2012 11:10 AM, wujianguo wrote: >> On 2012-11-23 18:44, Tang Chen wrote: >>> [What we are doing] >>> This patchset provide a boot option for user to specify ZONE_MOVABLE memory >>> map for each node in the system. >>> >>> movablecore_map=nn[KMG]@ss[KMG] >>> >> >> Hi Tang, >> DMA address can't be set as movable, if some one boot kernel with >> movablecore_map=4G@0xa00000 or other memory region that contains DMA address, >> system maybe boot failed. Should this case be handled or mentioned >> in the change log and kernel-parameters.txt? > > Hi Wu, > > Right, DMA address can't be set as movable. And I should have mentioned > it in the doc more clear. :) > > Actually, the situation is not only for DMA address. Because we limited > the memblock allocation, even if users did not specified the DMA > address, but set too much memory as movable, which means there was too > little memory for kernel to use, kernel will also fail to boot. > > I added the following info into doc, but obviously it was not clear > enough. :) > + If kernelcore or movablecore is also specified, > + movablecore_map will have higher priority to be > + satisfied. So the administrator should be careful that > + the amount of movablecore_map areas are not too large. > + Otherwise kernel won't have enough memory to start. > > > And about how to fix it, as you said, we can handle the situation if > user specified DMA address as movable. But how to handle "too little > memory for kernel to start" case ? Is there any info about how much > at least memory kernel needs ? > As I know, bootmem is mostly used by page structs when CONFIG_SPARSEMEM=y. But it is hard to calculate how much bootmem is needed exactly. > > Thanks for the comments. :) > >> >> Thanks, >> Jianguo Wu >> > > > > . > -- 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>