/dev/oldmem provides the interface for us to access the "old memory" in the dump-capture kernel. Unfortunately, no one actually uses this interface. And this interface could actually cause some real problems if used on ia64 where the cached/uncached accesses are mixed. See the discussion from the link: https://lkml.org/lkml/2013/4/12/386. So Eric suggested that we should remove /dev/oldmem as an unused piece of code. Besides, we used a global variable saved_max_pfn to let the capture kernel know the amount of memory that the previous kernel used. And for almost all architectures (except x86. In x86, saved_max_pfn is used by detect_calgary()), the only user of this variable is the read_oldmem interface of /dev/oldmem, so also remove the setting for saved_max_pfn in those architectures. -v2: Keep /dev/oldmem and its number 12 in case this number will get reused in the future. And mark it obsolete since /dev/oldmem will be removed from kernel. Zhang Yanfei (7): /dev/oldmem: Remove this interface Documentation/devices.txt: Mark /dev/oldmem obsolete Documentation/kdump/kdump.txt: Remove /dev/oldmem description mips: Remove savemaxmem parameter setup powerpc: Remove savemaxmem parameter setup ia64: Remove setting for saved_max_pfn s390: Remove setting for saved_max_pfn Documentation/devices.txt | 3 +- Documentation/kdump/kdump.txt | 31 +++++-------------------- arch/ia64/kernel/efi.c | 5 ---- arch/mips/kernel/crash_dump.c | 10 -------- arch/powerpc/kernel/crash_dump.c | 10 -------- arch/s390/kernel/setup.c | 4 --- drivers/char/mem.c | 47 -------------------------------------- 7 files changed, 7 insertions(+), 103 deletions(-)
