diff options
Diffstat (limited to 'arch/x86/mm/numa_emulation.c')
| -rw-r--r-- | arch/x86/mm/numa_emulation.c | 29 |
1 files changed, 26 insertions, 3 deletions
diff --git a/arch/x86/mm/numa_emulation.c b/arch/x86/mm/numa_emulation.c index 23fa2d00253..607a2e8bc87 100644 --- a/arch/x86/mm/numa_emulation.c +++ b/arch/x86/mm/numa_emulation.c @@ -267,9 +267,32 @@ static int __init split_nodes_size_interleave(struct numa_meminfo *ei, return 0; } -/* - * Sets up the system RAM area from start_pfn to last_pfn according to the - * numa=fake command-line option. +/** + * numa_emulation - Emulate NUMA nodes + * @numa_meminfo: NUMA configuration to massage + * @numa_dist_cnt: The size of the physical NUMA distance table + * + * Emulate NUMA nodes according to the numa=fake kernel parameter. + * @numa_meminfo contains the physical memory configuration and is modified + * to reflect the emulated configuration on success. @numa_dist_cnt is + * used to determine the size of the physical distance table. + * + * On success, the following modifications are made. + * + * - @numa_meminfo is updated to reflect the emulated nodes. + * + * - __apicid_to_node[] is updated such that APIC IDs are mapped to the + * emulated nodes. + * + * - NUMA distance table is rebuilt to represent distances between emulated + * nodes. The distances are determined considering how emulated nodes + * are mapped to physical nodes and match the actual distances. + * + * - emu_nid_to_phys[] reflects how emulated nodes are mapped to physical + * nodes. This is used by numa_add_cpu() and numa_remove_cpu(). + * + * If emulation is not enabled or fails, emu_nid_to_phys[] is filled with + * identity mapping and no other modification is made. */ void __init numa_emulation(struct numa_meminfo *numa_meminfo, int numa_dist_cnt) { |