On Thu, Aug 21, 2025 at 01:35:35AM -0700, Breno Leitao wrote: > I have another question. I assume it’s not possible to allocate only the > CMA crashkernel area for the kdump kernel, since we need to keep the > loaded kernel in the crashkernel area while the system is running. > Therefore, specifying crashkernel=X (without ',cma') is necessary.
exactly > At the same time, since the crashdump environment will use CMA, the > crashkernel area itself doesn’t need to be very large, as the CMA space > will be allocated later. > > With that in mind, how do I find what is the recommended size for the > crashkernel area, assuming the CMA area will be more than sufficient at > runtime? > > Does it need ot be much higher than the size of kdump kernel and initrd? I don't have a good answer now - I have this on my to-do list and I need to investigate this more to come up with a formula to calculate the required size to include this in the kdump tool I maintain for SUSE. When testing the kernel part I used crashkernel=100M crashkernel=XXX,cma on a machine that would normally require something like crashkernel=430M. -- Jiri Bohac <jbo...@suse.cz> SUSE Labs, Prague, Czechia
