On Friday 04 January 2008 16:49, Neil Horman wrote: > On Fri, Jan 04, 2008 at 04:00:26PM +0100, Stanislaw Gruszka wrote: > > On Friday 04 January 2008 14:55, Neil Horman wrote: > > > > It is possible to achieve valid vmcore when first is x86_64 and capture > > > > is i386 ? > > > Possible I think, but not reliable. If oldmem has regions to capture above the > > > 4GB range, a 386 kernel won't be able to access those addresses, and as such, > > > you won't get a complete vmcore. > > Uffff, I missed this fact. > > > > > I'm also confused about what exactly you are trying to accomplish. Why are you > > > trying to use an x86 kernel to capture a x86_64 vmcore? The available > > System load from flash and there is limited space. I tried to do one capture > > kernel, but see this was bad idea. I will scarify another 2MB and make separate > > image for x86_64. > > > > I'm still not quite understanding, the kernel image that you used to initally > boot the box should be suitable for loading as the kdump image. Even if you're > using i386 instead of x86_64 as your kdump kernel, you still need to maintain > two images. Turn on CONFIG_RELOCATABLE and using same kernel for work and capture is the best for size requirement. However size is not only one requirement, I need to capture kernel work reliably. RELOCATABLE is masked as experimental, so I like to avoid it. Additionally, if I use same kernel for capture, it could have same bugs and crash too during start up. So I decided to use separate 2.6.16.y kernel for capture. This version, maintained by Adrian Bunk, have many bug fixes and I think is very stable. Kernel config is different too, I do not only remove device drivers and modules, but also hardcoded things from Process Type and Features, Power Management and so on ... , just enough to boot and setup network with minimal probability of crash. Stanislaw Gruszka
