[PATCH] kexec/powerpc: fix exporting memory limit

Michael Ellerman mpe at ellerman.id.au
Thu Mar 6 19:47:38 EST 2014


On Thu, 2014-03-06 at 18:24 +0400, Nikita Yushchenko wrote:
> When preparing dump-capturing kernel, kexec userspace tool needs to know
> actual amount of memory used by the running kernel. This may differ from
> extire available DRAM for a couple of reasons. To address this issue,
> kdump kernel support code injects several attributes into device tree that
> are later captured by userspace kexec tool via /proc interface.
> 
> One such attrubute is 'chosen/linux,memory_limit' that is used to pass
> memory limit of the running kernel.
> 
> This was initialized using kernel's 'memory_limit' variable, that is set
> by early init code based on mem= kernel parameter and other reasons.
> 
> But there are cases when memory_limit variable does not contain proper
> information. One such case is when !CONFIG_HIGHMEM kernel runs on system
> with memory large enough not to fit into lowmem.

Why doesn't the !CONFIG_HIGHMEM code update memory_limit to reflect reality.

cheers





More information about the kexec mailing list