On Sat, Dec 16, 2006 at 06:43:13PM +0100, Guennadi Liakhovetski wrote: > Hi > > A simple question: do I understand it right that at the moment memory for > new kernel is reserved at boot time? What does it actually mean - this > memory is not used at all by the system (kernel and user) or only not used > for certain operations, e.g., DMA, as mentioned in > arch/i386/kernel/machine_kexec.c? If the latter, I could understand it, > that if the current kernel crashes, you might not be able to stop DMA > operations (?). Am I right or is there some other reason? >
Hi Guennadi, Just that a chunk of memory got reserved for very early for specific purposes. In this case for loading a capture kernel. So this memory is not used by kernel for any other purposes except loading a capture kernel (kexec system call). For kernel these page frames are already reserved, hence it never allocates these page frames to user space, hence user space never uses it. As these pages are reserved, they don't get allocated to anybody, no body sets up DMA to this region. (Excluding the case of a kernel bug where somebody sets up DMA to reserved region unitentionally). Thanks Vivek _______________________________________________ fastboot mailing list [email protected] https://lists.osdl.org/mailman/listinfo/fastboot
