On Tue, Jan 27, 2009 at 12:12:11AM -0800, Andrew Morton wrote: > On Tue, 20 Jan 2009 10:22:56 -0500 Vivek Goyal <vgoyal at redhat.com> wrote: > > > On Tue, Jan 20, 2009 at 10:09:58AM -0500, Neil Horman wrote: > > > On Tue, Jan 20, 2009 at 09:15:51AM -0500, Vivek Goyal wrote: > > > > On Mon, Jan 19, 2009 at 04:21:27PM -0500, Neil Horman wrote: > > > > > Hey all- > > > > > It would be nice to be able to extract the dmesg log from a vmcore file > > > > > without needing to keep the debug symbols for the running kernel handy all the > > > > > time. We have a facility to do this in /proc/vmcore. This patch adds the > > > > > log_buf and log_end symbols to the vmcoreinfo area so that tools (like > > > > > makedumpfile) can easily extract the dmesg logs from a vmcore image. > > > > > > > > > > > > > It would be nice to get dmesg log if debug symbols are not around. Can't > > > > we use System.map for getting symbol addresses? vmcoreinfo had started > > > > small and seems to be growing now. I am thinking down the line will making > > > > use of System.map for such cases make sense? > > > > > > > > > > System.map only include exported and public symbols. log_buf and log_end are > > > static, and not reported in the System.map. Its a nice idea, but not > > > comprehensive for everything in the kernel. > > > > > > ><snip> > > > > > > > > Will it be an issue if we make log_buf and log_end non static and directly > > > > access these in kexec.c? > > > > > > > I had considered that, but was a bit hesitant to do so, since it exposes the > > > internal implementation of the dmesg buffer. In the event someone disables > > > CONFIG_PRINTK, thats just more code we need to ifdef. With this implementation > > > we just stub out the log_buf_setup function, and let that be that. It seems > > > more consice to me this way. > > > > > > > Makes sense to me. > > > > Acked-by: Vivek Goyal <vgoyal at redhat.com> > > > > I rewrote the title to > > kexec: add dmesg log symbols to /proc/vmcoreinfo lists > > it's nice to identify which subsystem is responsible for a patch. > > I also did all the below. Please check it. (Is anyone else reading all > this stuff??) > > Hey Andrew- Yes, that all looks fine, thank. I'm not sure of the advantage of an inline over a #define in the event that CONFIG_PRINTK isn't defined, but its fine with me either way. Much appreciated! Neil >
