On Sat, May 25, 2013 at 04:25:21PM -0700, Eric W. Biederman wrote: > Zhang Yanfei <zhangyanfei.yes at gmail.com> writes: > > > /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. > > Except for the devices.txt update. > > Acked-by: "Eric W. Biederman" <ebiederm at xmission.com> Eric, Should we schedule the removal of this interface after 1-2 releases and give a warning once if anybody opens /dev/oldmem and tell them to use /proc/vmcore instead? I am kind of inclined towards warning approarch. If there is any xyz /dev/oldmem user in the wild out there, he/she atleast gets a chance to migrate to /proc/vmcore. Thanks Vivek
