diff options
Diffstat (limited to 'arch/s390')
| -rw-r--r-- | arch/s390/Kconfig | 37 | ||||
| -rw-r--r-- | arch/s390/include/asm/numa.h | 4 | ||||
| -rw-r--r-- | arch/s390/numa/Makefile | 1 | ||||
| -rw-r--r-- | arch/s390/numa/mode_emu.c | 511 | ||||
| -rw-r--r-- | arch/s390/numa/numa.c | 4 | ||||
| -rw-r--r-- | arch/s390/numa/numa_mode.h | 1 |
6 files changed, 558 insertions, 0 deletions
diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig index 25510ad..cb418dc 100644 --- a/arch/s390/Kconfig +++ b/arch/s390/Kconfig @@ -423,6 +423,43 @@ config NODES_SHIFT Specify the maximum number of NUMA nodes available on the target system. Increases memory reserved to accommodate various tables. +menu "Select NUMA modes" + depends on NUMA + +config NUMA_EMU + bool "NUMA emulation" + default y + help + Numa emulation mode will split the available system memory into + equal chunks which then are distributed over the configured number + of nodes in a round-robin manner. + + The number of fake nodes is limited by the number of available memory + chunks (i.e. memory size / fake size) and the number of supported + nodes in the kernel. + + The CPUs are assigned to the nodes in a way that partially respects + the original machine topology (if supported by the machine). + Fair distribution of the CPUs is not guaranteed. + +config EMU_SIZE + hex "NUMA emulation memory chunk size" + default 0x10000000 + range 0x400000 0x100000000 + depends on NUMA_EMU + help + Select the default size by which the memory is chopped and then + assigned to emulated NUMA nodes. + + This can be overridden by specifying + + emu_size=<n> + + on the kernel command line where also suffixes K, M, G, and T are + supported. + +endmenu + config SCHED_MC def_bool n diff --git a/arch/s390/include/asm/numa.h b/arch/s390/include/asm/numa.h index ea4edbf..2a0efc6 100644 --- a/arch/s390/include/asm/numa.h +++ b/arch/s390/include/asm/numa.h @@ -26,6 +26,10 @@ extern int numa_debug_enabled; static inline void numa_setup(void) { } static inline void numa_update_cpu_topology(void) { } +static inline int numa_pfn_to_nid(unsigned long pfn) +{ + return 0; +} #endif /* CONFIG_NUMA */ #endif /* _ASM_S390_NUMA_H */ diff --git a/arch/s390/numa/Makefile b/arch/s390/numa/Makefile index 3137229..f94ecaf 100644 --- a/arch/s390/numa/Makefile +++ b/arch/s390/numa/Makefile @@ -1,2 +1,3 @@ obj-y += numa.o obj-y += toptree.o +obj-$(CONFIG_NUMA_EMU) += mode_emu.o diff --git a/arch/s390/numa/mode_emu.c b/arch/s390/numa/mode_emu.c new file mode 100644 index 0000000..9d4e1e1 --- /dev/null +++ b/arch/s390/numa/mode_emu.c @@ -0,0 +1,511 @@ +/* + * NUMA support for s390 + * + * NUMA emulation (aka fake NUMA) distributes the available memory to nodes + * without using real topology information about the physical memory of the + * machine. + * + * It distributes the available CPUs to nodes while respecting the original + * machine topology information. This is done by trying to avoid to separate + * CPUs which reside on the same book or even on the same MC. + * + * Because the current Linux scheduler code requires a stable cpu to node + * mapping, cores are pinned to nodes when the first CPU thread is set online. + * + * Copyright IBM Corp. 2015 + */ + +#define KMSG_COMPONENT "numa_emu" +#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt + +#include <linux/kernel.h> +#include <linux/cpumask.h> +#include <linux/memblock.h> +#include <linux/node.h> +#include <linux/memory.h> +#include <asm/smp.h> +#include <asm/topology.h> +#include "numa_mode.h" +#include "toptree.h" + +/* Distances between the different system components */ +#define DIST_EMPTY 0 +#define DIST_CORE 1 +#define DIST_MC 2 +#define DIST_BOOK 3 +#define DIST_MAX 4 + +/* Node distance reported to common code */ +#define EMU_NODE_DIST 10 + +/* Node ID for free (not yet pinned) cores */ +#define NODE_ID_FREE -1 + +/* Different levels of toptree */ +enum toptree_level {CORE, MC, BOOK, NODE, TOPOLOGY}; + +/* The two toptree IDs */ +enum {TOPTREE_ID_PHYS, TOPTREE_ID_NUMA}; + +/* Number of NUMA nodes */ +static int emu_nodes = 1; +/* NUMA stripe size */ +static unsigned long emu_size; +/* Pinned core to node mapping */ +static int cores_to_node_id[CONFIG_NR_CPUS]; +/* Total number of pinned cores */ +static int cores_total; +/* Number of cores per node without extra cores */ +static int cores_per_node_target; +/* Number of cores pinned to node */ +static int cores_per_node[MAX_NUMNODES]; + +/* + * Pin a core to a node + */ +static void pin_core_to_node(int core_id, int node_id) +{ + if (cores_to_node_id[core_id] == NODE_ID_FREE) { + cores_per_node[node_id]++; + cores_to_node_id[core_id] = node_id; + cores_total++; + } else { + WARN_ON(cores_to_node_id[core_id] != node_id); + } +} + +/* + * Number of pinned cores of a node + */ +static int cores_pinned(struct toptree *node) +{ + return cores_per_node[node->id]; +} + +/* + * ID of the node where the core is pinned (or NODE_ID_FREE) + */ +static int core_pinned_to_node_id(struct toptree *core) +{ + return cores_to_node_id[core->id]; +} + +/* + * Number of cores in the tree that are not yet pinned + */ +static int cores_free(struct toptree *tree) +{ + struct toptree *core; + int count = 0; + + toptree_for_each(core, tree, CORE) { + if (core_pinned_to_node_id(core) == NODE_ID_FREE) + count++; + } + return count; +} + +/* + * Return node of core + */ +static struct toptree *core_node(struct toptree *core) +{ + return core->parent->parent->parent; +} + +/* + * Return book of core + */ +static struct toptree *core_book(struct toptree *core) +{ + return core->parent->parent; +} + +/* + * Return mc of core + */ +static struct toptree *core_mc(struct toptree *core) +{ + return core->parent; +} + +/* + * Distance between two cores + */ +static int dist_core_to_core(struct toptree *core1, struct toptree *core2) +{ + if (core_book(core1)->id != core_book(core2)->id) + return DIST_BOOK; + if (core_mc(core1)->id != core_mc(core2)->id) + return DIST_MC; + /* Same core or sibling on same MC */ + return DIST_CORE; +} + +/* + * Distance of a node to a core + */ +static int dist_node_to_core(struct toptree *node, struct toptree *core) +{ + struct toptree *core_node; + int dist_min = DIST_MAX; + + toptree_for_each(core_node, node, CORE) + dist_min = min(dist_min, dist_core_to_core(core_node, core)); + return dist_min == DIST_MAX ? DIST_EMPTY : dist_min; +} + +/* + * Unify will delete empty nodes, therefore recreate nodes. + */ +static void toptree_unify_tree(struct toptree *tree) +{ + int nid; + + toptree_unify(tree); + for (nid = 0; nid < emu_nodes; nid++) + toptree_get_child(tree, nid); +} + +/* + * Find the best/nearest node for a given core and ensure that no node + * gets more than "cores_per_node_target + extra" cores. + */ +static struct toptree *node_for_core(struct toptree *numa, struct toptree *core, + int extra) +{ + struct toptree *node, *node_best = NULL; + int dist_cur, dist_best; + + dist_best = DIST_MAX; + node_best = NULL; + toptree_for_each(node, numa, NODE) { + /* Already pinned cores must use their nodes */ + if (core_pinned_to_node_id(core) == node->id) { + node_best = node; + break; + } + /* Skip nodes that already have enough cores */ + if (cores_pinned(node) >= cores_per_node_target + extra) + continue; + dist_cur = dist_node_to_core(node, core); + if (dist_cur < dist_best) { + dist_best = dist_cur; + node_best = node; + } + } + return node_best; +} + +/* + * Find the best node for each core with respect to "extra" core count + */ +static void toptree_to_numa_single(struct toptree *numa, struct toptree *phys, + int extra) +{ + struct toptree *node, *core, *tmp; + + toptree_for_each_safe(core, tmp, phys, CORE) { + node = node_for_core(numa, core, extra); + if (!node) + return; + toptree_move(core, node); + pin_core_to_node(core->id, node->id); + } +} + +/* + * Move structures of given level to specified NUMA node + */ +static void move_level_to_numa_node(struct toptree *node, struct toptree *phys, + enum toptree_level level, bool perfect) +{ + struct toptree *cur, *tmp; + int cores_free; + + toptree_for_each_safe(cur, tmp, phys, level) { + cores_free = cores_per_node_target - toptree_count(node, CORE); + if (perfect) { + if (cores_free == toptree_count(cur, CORE)) + toptree_move(cur, node); + } else { + if (cores_free >= toptree_count(cur, CORE)) + toptree_move(cur, node); + } + } +} + +/* + * Move structures of a given level to NUMA nodes. If "perfect" is specified + * move only perfectly fitting structures. Otherwise move also smaller + * than needed structures. + */ +static void move_level_to_numa(struct toptree *numa, struct toptree *phys, + enum toptree_level level, bool perfect) +{ + struct toptree *node; + + toptree_for_each(node, numa, NODE) + move_level_to_numa_node(node, phys, level, perfect); +} + +/* + * For the first run try to move the big structures + */ +static void toptree_to_numa_first(struct toptree *numa, struct toptree *phys) +{ + struct toptree *core; + + /* Always try to move perfectly fitting structures first */ + move_level_to_numa(numa, phys, BOOK, true); + move_level_to_numa(numa, phys, BOOK, false); + move_level_to_numa(numa, phys, MC, true); + move_level_to_numa(numa, phys, MC, false); + /* Now pin all the moved cores */ + toptree_for_each(core, numa, CORE) + pin_core_to_node(core->id, core_node(core)->id); +} + +/* + * Allocate new topology and create required nodes + */ +static struct toptree *toptree_new(int id, int nodes) +{ + struct toptree *tree; + int nid; + + tree = toptree_alloc(TOPOLOGY, id); + if (!tree) + goto fail; + for (nid = 0; nid < nodes; nid++) { + if (!toptree_get_child(tree, nid)) + goto fail; + } + return tree; +fail: + panic("NUMA emulation could not allocate topology"); +} + +/* + * Move cores from physical topology into NUMA target topology + * and try to keep as much of the physical topology as possible. + */ +static struct toptree *toptree_to_numa(struct toptree *phys) +{ + static int first = 1; + struct toptree *numa; + + cores_per_node_target = (cores_total + cores_free(phys)) / emu_nodes; + numa = toptree_new(TOPTREE_ID_NUMA, emu_nodes); + if (first) { + toptree_to_numa_first(numa, phys); + first = 0; + } + toptree_to_numa_single(numa, phys, 0); + toptree_to_numa_single(numa, phys, 1); + toptree_unify_tree(numa); + + WARN_ON(cpumask_weight(&phys->mask)); + return numa; +} + +/* + * Create a toptree out of the physical topology that we got from the hypervisor + */ +static struct toptree *toptree_from_topology(void) +{ + struct toptree *phys, *node, *book, *mc, *core; + struct cpu_topology_s390 *top; + int cpu; + + phys = toptree_new(TOPTREE_ID_PHYS, 1); + + for_each_online_cpu(cpu) { + top = &per_cpu(cpu_topology, cpu); + node = toptree_get_child(phys, 0); + book = toptree_get_child(node, top->book_id); + mc = toptree_get_child(book, top->socket_id); + core = toptree_get_child(mc, top->core_id); + if (!book || !mc || !core) + panic("NUMA emulation could not allocate memory"); + cpumask_set_cpu(cpu, &core->mask); + toptree_update_mask(mc); + } + return phys; +} + +/* + * Add toptree core to topology and create correct CPU masks + */ +static void topology_add_core(struct toptree *core) +{ + struct cpu_topology_s390 *top; + int cpu; + + for_each_cpu(cpu, &core->mask) { + top = &per_cpu(cpu_topology, cpu); + cpumask_copy(&top->thread_mask, &core->mask); + cpumask_copy(&top->core_mask, &core_mc(core)->mask); + cpumask_copy(&top->book_mask, &core_book(core)->mask); + cpumask_set_cpu(cpu, node_to_cpumask_map[core_node(core)->id]); + top->node_id = core_node(core)->id; + } +} + +/* + * Apply toptree to topology and create CPU masks + */ +static void toptree_to_topology(struct toptree *numa) +{ + struct toptree *core; + int i; + + /* Clear all node masks */ + for (i = 0; i < MAX_NUMNODES; i++) + cpumask_clear(node_to_cpumask_map[i]); + + /* Rebuild all masks */ + toptree_for_each(core, numa, CORE) + topology_add_core(core); +} + +/* + * Show the node to core mapping + */ +static void print_node_to_core_map(void) +{ + int nid, cid; + + if (!numa_debug_enabled) + return; + printk(KERN_DEBUG "NUMA node to core mapping\n"); + for (nid = 0; nid < emu_nodes; nid++) { + printk(KERN_DEBUG " node %3d: ", nid); + for (cid = 0; cid < ARRAY_SIZE(cores_to_node_id); cid++) { + if (cores_to_node_id[cid] == nid) + printk(KERN_CONT "%d ", cid); + } + printk(KERN_CONT "\n"); + } +} + +/* + * Transfer physical topology into a NUMA topology and modify CPU masks + * according to the NUMA topology. + * + * This function is called under the CPU hotplug lock. + */ +static void emu_update_cpu_topology(void) +{ + struct toptree *phys, *numa; + + phys = toptree_from_topology(); + numa = toptree_to_numa(phys); + toptree_free(phys); + toptree_to_topology(numa); + toptree_free(numa); + print_node_to_core_map(); +} + +/* + * If emu_size is not set, use CONFIG_EMU_SIZE. Then round to minimum + * alignment (needed for memory hotplug). + */ +static unsigned long emu_setup_size_adjust(unsigned long size) +{ + size = size ? : CONFIG_EMU_SIZE; + size = roundup(size, memory_block_size_bytes()); + return size; +} + +/* + * If we have not enough memory for the specified nodes, reduce the node count. + */ +static int emu_setup_nodes_adjust(int nodes) +{ + int nodes_max; + + nodes_max = memblock.memory.total_size / emu_size; + nodes_max = max(nodes_max, 1); + if (nodes_max >= nodes) + return nodes; + pr_warn("Not enough memory for %d nodes, reducing node count\n", nodes); + return nodes_max; +} + +/* + * Early emu setup + */ +static void emu_setup(void) +{ + int i; + + emu_size = emu_setup_size_adjust(emu_size); + emu_nodes = emu_setup_nodes_adjust(emu_nodes); + for (i = 0; i < ARRAY_SIZE(cores_to_node_id); i++) + cores_to_node_id[i] = NODE_ID_FREE; + pr_info("Creating %d nodes with memory stripe size %ld MB\n", + emu_nodes, emu_size >> 20); +} + +/* + * Return node id for given page number + */ +static int emu_pfn_to_nid(unsigned long pfn) +{ + return (pfn / (emu_size >> PAGE_SHIFT)) % emu_nodes; +} + +/* + * Return stripe size + */ +static unsigned long emu_align(void) +{ + return emu_size; +} + +/* + * Return distance between two nodes + */ +static int emu_distance(int node1, int node2) +{ + return (node1 != node2) * EMU_NODE_DIST; +} + +/* + * Define callbacks for generic s390 NUMA infrastructure + */ +const struct numa_mode numa_mode_emu = { + .name = "emu", + .setup = emu_setup, + .update_cpu_topology = emu_update_cpu_topology, + .__pfn_to_nid = emu_pfn_to_nid, + .align = emu_align, + .distance = emu_distance, +}; + +/* + * Kernel parameter: emu_nodes=<n> + */ +static int __init early_parse_emu_nodes(char *p) +{ + int count; + + if (kstrtoint(p, 0, &count) != 0 || count <= 0) + return 0; + if (count <= 0) + return 0; + emu_nodes = min(count, MAX_NUMNODES); + return 0; +} +early_param("emu_nodes", early_parse_emu_nodes); + +/* + * Kernel parameter: emu_size=[<n>[k|M|G|T]] + */ +static int __init early_parse_emu_size(char *p) +{ + emu_size = memparse(p, NULL); + return 0; +} +early_param("emu_size", early_parse_emu_size); diff --git a/arch/s390/numa/numa.c b/arch/s390/numa/numa.c index 0416a36..09b1d23 100644 --- a/arch/s390/numa/numa.c +++ b/arch/s390/numa/numa.c @@ -175,6 +175,10 @@ static int __init parse_numa(char *parm) { if (strcmp(parm, numa_mode_plain.name) == 0) mode = &numa_mode_plain; +#ifdef CONFIG_NUMA_EMU + if (strcmp(parm, numa_mode_emu.name) == 0) + mode = &numa_mode_emu; +#endif return 0; } early_param("numa", parse_numa); diff --git a/arch/s390/numa/numa_mode.h b/arch/s390/numa/numa_mode.h index 7756598..08953b0b 100644 --- a/arch/s390/numa/numa_mode.h +++ b/arch/s390/numa/numa_mode.h @@ -19,5 +19,6 @@ struct numa_mode { }; extern const struct numa_mode numa_mode_plain; +extern const struct numa_mode numa_mode_emu; #endif /* __S390_NUMA_MODE_H */ |