Re: [Crash-utility] handling missing kdump pages in diskdump format

Hi Dave, 2007/04/03 09:40:56 -0400, Dave Anderson <anderson(a)redhat.com&gt; wrote: >> It is a good idea that "help -n" shows dump_level. >> >> I checked the code of diskdumputils-1.3.25, and I found the dumpfilter >> command refers to diskdump->total_ram_blocks. In struct disk_dump_header, >> there is no member not referred to by neither the crash utility or diskdumputils. >> My proposal (changing total_ram_blocks for dump_level) was not good. >> >> I think it is enough that the member for dump_level is added into the >> sub header of kdump (struct kdump_sub_header) only for kdump. >> Is the change for diskdump necessary, too ? >> >> > >If this were to be restricted to kdump only, then it would be >safe to add a field to the kdump_sub_header since it contains >only one field. > >Whether it is necessary for diskdump is up to the diskdump >maintainers to decide. But if they want to do it, they would >have to come up with different manner of adding it to the >disk_dump_sub_header structure, because of the way >that it's declared, i.e., using "long elf_regs" as a placeholder >to describe the start of the processor-dependent register >set. They'd need to define a new disk_dump_sub_header >version that alternatively would be used depending upon >the header->version number. We asked the diskdump developers (Indoh-san, Akiyama-san) how to display diskdump's dump_level, and they said that changing of file format is not necessary for displaying the dump_level. And they gave us a good advice that the crash utility can get diskdump's dump_level by using a symbol "dump_level" like the following: int get_dump_level(void) { if (symbol_exists("dump_level")) { int dump_level; readmem(symbol_value("dump_level"), KVADDR, &dump_level, sizeof(dump_level), "dump_level", FAULT_ON_ERROR); return dump_level; } else ... I think it is a good way because the crash utility can get diskdump's dump_level of the existing dumpfile. I propose the following way for it. Please let me know your opinion. - If a symbol "dump_level" is present (diskdump), the dump_level is taken from a symbol "dump_level". - Else if a dumpfile is kdump's and header_version is 1 or more, the dump_level taken from a new member "kdump_sub_header->dump_level". Thanks Ken'ichi Ohmichi