Tweak generic node topology in case of CONFIG_HIGHMEM enabled to prioritize allocations from ZONE_HIGHMEM to avoid ZONE_NORMAL pressure. Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@xxxxxxxxxxxx> --- Tested on both NSIM and HSDK (require memory apertures remmaping and device tree patching) arch/arc/include/asm/Kbuild | 1 - arch/arc/include/asm/topology.h | 30 ++++++++++++++++++++++++++++++ 2 files changed, 30 insertions(+), 1 deletion(-) create mode 100644 arch/arc/include/asm/topology.h diff --git a/arch/arc/include/asm/Kbuild b/arch/arc/include/asm/Kbuild index caa270261521..e64e0439baff 100644 --- a/arch/arc/include/asm/Kbuild +++ b/arch/arc/include/asm/Kbuild @@ -18,7 +18,6 @@ generic-y += msi.h generic-y += parport.h generic-y += percpu.h generic-y += preempt.h -generic-y += topology.h generic-y += trace_clock.h generic-y += user.h generic-y += vga.h diff --git a/arch/arc/include/asm/topology.h b/arch/arc/include/asm/topology.h new file mode 100644 index 000000000000..c273506931c9 --- /dev/null +++ b/arch/arc/include/asm/topology.h @@ -0,0 +1,30 @@ +#ifndef _ASM_ARC_TOPOLOGY_H +#define _ASM_ARC_TOPOLOGY_H + +/* + * On ARC (w/o PAE) HIGHMEM addresses are smaller (0x0 based) than addresses in + * NORMAL aka low memory (0x8000_0000 based). + * Thus HIGHMEM on ARC is imlemented with DISCONTIGMEM which requires multiple + * nodes. So here is memory node map depending on the CONFIG_HIGHMEM + * enabled/disabled: + * + * CONFIG_HIGHMEM disabled: + * - node 0: ZONE_NORMAL memory only. + * + * CONFIG_HIGHMEM enabled: + * - node 0: ZONE_NORMAL memory only. + * - node 1: ZONE_HIGHMEM memory only. + * + * In case of CONFIG_HIGHMEM enabled we tweak generic node topology and mark + * node 1 as the closest to all CPUs to prioritize allocations from ZONE_HIGHMEM + * where it is possible to avoid ZONE_NORMAL pressure. + */ +#ifdef CONFIG_HIGHMEM +#define cpu_to_node(cpu) ((void)(cpu), 1) +#define cpu_to_mem(cpu) ((void)(cpu), 1) +#define cpumask_of_node(node) ((node) == 1 ? cpu_online_mask : cpu_none_mask) +#endif /* CONFIG_HIGHMEM */ + +#include <asm-generic/topology.h> + +#endif /* _ASM_ARC_TOPOLOGY_H */ -- 2.14.5
