Hello Ken'inchi, On Thu, 2011-03-17 at 15:39 +0900, Ken'ichi Ohmichi wrote: > Hi Mahesh, > > On Tue, 15 Mar 2011 22:39:23 +0530 > Mahesh J Salgaonkar <mahesh at linux.vnet.ibm.com> wrote: > > > > From: Mahesh Salgaonkar <mahesh at linux.vnet.ibm.com> > > > > While excluding free pages from s390x dumps taken on LPAR, makedumpfile > > fails to convert page address to pfn. The reason is, the memory for > > mem_section structure is allocated below '_stext' and since KVBASE is > > set to SYMBOL(_stext), the function is_kvaddr() fails and return NULL > > address. > > Why do we need this patch ? > to support the latest kernel version of s390 ? > or to support LPAR of s390 ? The problem is that on s390 depending on the kernel configuration it can happen that memory below _stext is available for buffer allocation. Therefore the mem_section structure has been allocated below _stext. On s390 the kernel page tables have a 1:1 mapping from 0 to memory_end (memory holes are possible). Therefore I think the check "> 0" is ok for s390. > > I'd like to know whether we need a similar change for the other architecture. > I will appreciate if getting a hint. Not sure, if other architectures use memory below _stext for buffer allocation. Michael
