Hi Fan San, On 10/11/17 at 10:28am, Chao Fan wrote: > Hi all, > > Here is a problem: > Here is a machine with several NUMA nodes and some of them are hot-pluggable, > It's not good for kernel to be extracted in the memory region of movable node. > But in current code, I print the address choosen by kaslr and found it may be > placed in movable node sometimes. To solve this problem, it's better to the > memory region choosen by kaslr to immovable node in kaslr.c. But the memory > infomation about if it's hot-pluggable is stored in ACPI SRAT table, which is > parsed after kernel is extracted. So we can't get the detail memory infomation > before extracting kernel. > > There are two methods to solve this problem: > > 1. Get and parse the srat table before kernel extracted, then mark the memory > region in movable node which should be avoided in kaslr. > I have send the patch: > https://www.spinics.net/lists/kernel/msg2595546.html > But the change is large and then here is the second method. > > 2. Extend the movable_node to movable_node=nn@ss, in which nn means > the size of memory in immovable node, and ss means the start position of > this memory region. > But it brings another question, it may be a little difficult for a normal > user to specify the nn and ss. Because it's hard for a user to know the value > of the memory in immovable node. > So I wonder if it's good to add a interface in /sys, like: > # cat /sys/device/system/memory/immovable_node You can post patch. By the way, can the existing /sys/devices/system/memory/memoryX/removable be used instead? Thanks Baoquan > nn@ss > nn@ss > ... > to show the two value. > When srat table is parsed in acpi_parse_memory_affinity, fill the value > and user can get and use them. > > If anyone has a better method, please let me know. > Any comments will be welcome. > > Thanks, > Chao Fan > > -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
