On 01/25/19 at 03:08pm, Borislav Petkov wrote: > On Fri, Jan 25, 2019 at 09:45:18PM +0800, Dave Young wrote: > > AFAIK, some people prefer to explictly reserve crash memory at high > > region even if it is possible to reserve at low area. May because > > <4G memory is limited on large server, they want to leave this for other > > use. > > > > Yinghai or Vivek should know more about the history, probably they can > > recall some initial reason. > > Yes, just "prefer" is not good enough. There should be a technical > reason why that's there. > > Also, if the user doesn't care, then the code should be free to force > "high" and thus probe a different range for allocation.
Another reason is in case ,high we will need automatically reserve a region in low area for swiotlb. So for example one use crashkernel=256M,high, actual reserved memory is 256M above 4G and another 256M under 4G for swiotlb. Normally it is not necessary for most people. Thus we can not make ,high as default. Thanks Dave _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec
