Hi Philipp, On 01/14/2014 08:52 PM, Philipp Hachtmann wrote: > Hello Grygorii, > > thank you for your comments. > > To clarify we have the following requirements for memblock: > > (1) Reserved areas can be declared before memory is added. > (2) The physical memory is detected once only. > (3) The free memory (i.e. not reserved) memory can be iterated to add > it to the buddy allocator. > (4) Memory designated to be mapped into the kernel address space can be > iterated. > (5) Kdump on s390 requires knowledge about the full system memory > layout. > > The s390 kdump implementation works a bit different from the > implementation on other architectures: The layout is not taken from the > production system and saved for the kdump kernel. Instead the kdump > kernel needs to gather information about the whole memory without > respect to locked out areas (like mem= and OLDMEM etc.). > > Without kdump's requirement it would of course be suitable and easy > just to remove memory from memblock.memory. But then this information > is lost for later use by kdump. > > The patch does not change any behaviour of the current API - whether it > is enabled or not. Sorry, for the delayed reply. My main concern here was that you are introducing new *generic* API, but in fact it is not generic, because it can't be re-used without huge rework of existing code. (at least as of wide usage of for_each_memblock(memory,...), because (if ARCH_MEMBLOCK_NOMAP=y) the meaning of "memory" ranges will be changed form "mapped memory" to "real phys memory"). And therefore, I've proposed to keep things as is and introduce phys_memory ranges instead, to store real phys memory configuration. > > The current patch seems to be overly complicated. > The following patch contains only the nomap functionality without any > cleanup and refactoring. I will post a V4 patch set which will contain > this patch. Regards, -grygorii -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href