diff options
Diffstat (limited to 'mm/mempolicy.c')
| -rw-r--r-- | mm/mempolicy.c | 283 |
1 files changed, 259 insertions, 24 deletions
diff --git a/mm/mempolicy.c b/mm/mempolicy.c index aaf54566cb6b..d1b315e98627 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -90,6 +90,7 @@ #include <linux/syscalls.h> #include <linux/ctype.h> #include <linux/mm_inline.h> +#include <linux/mmu_notifier.h> #include <asm/tlbflush.h> #include <asm/uaccess.h> @@ -117,6 +118,26 @@ static struct mempolicy default_policy = { .flags = MPOL_F_LOCAL, }; +static struct mempolicy preferred_node_policy[MAX_NUMNODES]; + +static struct mempolicy *get_task_policy(struct task_struct *p) +{ + struct mempolicy *pol = p->mempolicy; + int node; + + if (!pol) { + node = numa_node_id(); + if (node != -1) + pol = &preferred_node_policy[node]; + + /* preferred_node_policy is not initialised early in boot */ + if (!pol->mode) + pol = NULL; + } + + return pol; +} + static const struct mempolicy_operations { int (*create)(struct mempolicy *pol, const nodemask_t *nodes); /* @@ -254,7 +275,7 @@ static struct mempolicy *mpol_new(unsigned short mode, unsigned short flags, if (mode == MPOL_DEFAULT) { if (nodes && !nodes_empty(*nodes)) return ERR_PTR(-EINVAL); - return NULL; /* simply delete any existing policy */ + return NULL; } VM_BUG_ON(!nodes); @@ -269,6 +290,10 @@ static struct mempolicy *mpol_new(unsigned short mode, unsigned short flags, (flags & MPOL_F_RELATIVE_NODES))) return ERR_PTR(-EINVAL); } + } else if (mode == MPOL_LOCAL) { + if (!nodes_empty(*nodes)) + return ERR_PTR(-EINVAL); + mode = MPOL_PREFERRED; } else if (nodes_empty(*nodes)) return ERR_PTR(-EINVAL); policy = kmem_cache_alloc(policy_cache, GFP_KERNEL); @@ -561,6 +586,36 @@ static inline int check_pgd_range(struct vm_area_struct *vma, return 0; } +#ifdef CONFIG_ARCH_USES_NUMA_PROT_NONE +/* + * This is used to mark a range of virtual addresses to be inaccessible. + * These are later cleared by a NUMA hinting fault. Depending on these + * faults, pages may be migrated for better NUMA placement. + * + * This is assuming that NUMA faults are handled using PROT_NONE. If + * an architecture makes a different choice, it will need further + * changes to the core. + */ +unsigned long change_prot_numa(struct vm_area_struct *vma, + unsigned long addr, unsigned long end) +{ + int nr_updated; + BUILD_BUG_ON(_PAGE_NUMA != _PAGE_PROTNONE); + + nr_updated = change_protection(vma, addr, end, vma->vm_page_prot, 0, 1); + if (nr_updated) + count_vm_numa_events(NUMA_PTE_UPDATES, nr_updated); + + return nr_updated; +} +#else +static unsigned long change_prot_numa(struct vm_area_struct *vma, + unsigned long addr, unsigned long end) +{ + return 0; +} +#endif /* CONFIG_ARCH_USES_NUMA_PROT_NONE */ + /* * Check if all pages in a range are on a set of nodes. * If pagelist != NULL then isolate pages from the LRU and @@ -579,22 +634,32 @@ check_range(struct mm_struct *mm, unsigned long start, unsigned long end, return ERR_PTR(-EFAULT); prev = NULL; for (vma = first; vma && vma->vm_start < end; vma = vma->vm_next) { + unsigned long endvma = vma->vm_end; + + if (endvma > end) + endvma = end; + if (vma->vm_start > start) + start = vma->vm_start; + if (!(flags & MPOL_MF_DISCONTIG_OK)) { if (!vma->vm_next && vma->vm_end < end) return ERR_PTR(-EFAULT); if (prev && prev->vm_end < vma->vm_start) return ERR_PTR(-EFAULT); } - if (!is_vm_hugetlb_page(vma) && - ((flags & MPOL_MF_STRICT) || + + if (is_vm_hugetlb_page(vma)) + goto next; + + if (flags & MPOL_MF_LAZY) { + change_prot_numa(vma, start, endvma); + goto next; + } + + if ((flags & MPOL_MF_STRICT) || ((flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)) && - vma_migratable(vma)))) { - unsigned long endvma = vma->vm_end; + vma_migratable(vma))) { - if (endvma > end) - endvma = end; - if (vma->vm_start > start) - start = vma->vm_start; err = check_pgd_range(vma, start, endvma, nodes, flags, private); if (err) { @@ -602,6 +667,7 @@ check_range(struct mm_struct *mm, unsigned long start, unsigned long end, break; } } +next: prev = vma; } return first; @@ -961,7 +1027,8 @@ static int migrate_to_node(struct mm_struct *mm, int source, int dest, if (!list_empty(&pagelist)) { err = migrate_pages(&pagelist, new_node_page, dest, - false, MIGRATE_SYNC); + false, MIGRATE_SYNC, + MR_SYSCALL); if (err) putback_lru_pages(&pagelist); } @@ -1133,8 +1200,7 @@ static long do_mbind(unsigned long start, unsigned long len, int err; LIST_HEAD(pagelist); - if (flags & ~(unsigned long)(MPOL_MF_STRICT | - MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)) + if (flags & ~(unsigned long)MPOL_MF_VALID) return -EINVAL; if ((flags & MPOL_MF_MOVE_ALL) && !capable(CAP_SYS_NICE)) return -EPERM; @@ -1157,6 +1223,9 @@ static long do_mbind(unsigned long start, unsigned long len, if (IS_ERR(new)) return PTR_ERR(new); + if (flags & MPOL_MF_LAZY) + new->flags |= MPOL_F_MOF; + /* * If we are using the default policy then operation * on discontinuous address spaces is okay after all @@ -1193,21 +1262,24 @@ static long do_mbind(unsigned long start, unsigned long len, vma = check_range(mm, start, end, nmask, flags | MPOL_MF_INVERT, &pagelist); - err = PTR_ERR(vma); - if (!IS_ERR(vma)) { - int nr_failed = 0; - + err = PTR_ERR(vma); /* maybe ... */ + if (!IS_ERR(vma)) err = mbind_range(mm, start, end, new); + if (!err) { + int nr_failed = 0; + if (!list_empty(&pagelist)) { + WARN_ON_ONCE(flags & MPOL_MF_LAZY); nr_failed = migrate_pages(&pagelist, new_vma_page, (unsigned long)vma, - false, MIGRATE_SYNC); + false, MIGRATE_SYNC, + MR_MEMPOLICY_MBIND); if (nr_failed) putback_lru_pages(&pagelist); } - if (!err && nr_failed && (flags & MPOL_MF_STRICT)) + if (nr_failed && (flags & MPOL_MF_STRICT)) err = -EIO; } else putback_lru_pages(&pagelist); @@ -1546,7 +1618,7 @@ asmlinkage long compat_sys_mbind(compat_ulong_t start, compat_ulong_t len, struct mempolicy *get_vma_policy(struct task_struct *task, struct vm_area_struct *vma, unsigned long addr) { - struct mempolicy *pol = task->mempolicy; + struct mempolicy *pol = get_task_policy(task); if (vma) { if (vma->vm_ops && vma->vm_ops->get_policy) { @@ -1956,7 +2028,7 @@ retry_cpuset: */ struct page *alloc_pages_current(gfp_t gfp, unsigned order) { - struct mempolicy *pol = current->mempolicy; + struct mempolicy *pol = get_task_policy(current); struct page *page; unsigned int cpuset_mems_cookie; @@ -2140,6 +2212,115 @@ static void sp_free(struct sp_node *n) kmem_cache_free(sn_cache, n); } +/** + * mpol_misplaced - check whether current page node is valid in policy + * + * @page - page to be checked + * @vma - vm area where page mapped + * @addr - virtual address where page mapped + * + * Lookup current policy node id for vma,addr and "compare to" page's + * node id. + * + * Returns: + * -1 - not misplaced, page is in the right node + * node - node id where the page should be + * + * Policy determination "mimics" alloc_page_vma(). + * Called from fault path where we know the vma and faulting address. + */ +int mpol_misplaced(struct page *page, struct vm_area_struct *vma, unsigned long addr) +{ + struct mempolicy *pol; + struct zone *zone; + int curnid = page_to_nid(page); + unsigned long pgoff; + int polnid = -1; + int ret = -1; + + BUG_ON(!vma); + + pol = get_vma_policy(current, vma, addr); + if (!(pol->flags & MPOL_F_MOF)) + goto out; + + switch (pol->mode) { + case MPOL_INTERLEAVE: + BUG_ON(addr >= vma->vm_end); + BUG_ON(addr < vma->vm_start); + + pgoff = vma->vm_pgoff; + pgoff += (addr - vma->vm_start) >> PAGE_SHIFT; + polnid = offset_il_node(pol, vma, pgoff); + break; + + case MPOL_PREFERRED: + if (pol->flags & MPOL_F_LOCAL) + polnid = numa_node_id(); + else + polnid = pol->v.preferred_node; + break; + + case MPOL_BIND: + /* + * allows binding to multiple nodes. + * use current page if in policy nodemask, + * else select nearest allowed node, if any. + * If no allowed nodes, use current [!misplaced]. + */ + if (node_isset(curnid, pol->v.nodes)) + goto out; + (void)first_zones_zonelist( + node_zonelist(numa_node_id(), GFP_HIGHUSER), + gfp_zone(GFP_HIGHUSER), + &pol->v.nodes, &zone); + polnid = zone->node; + break; + + default: + BUG(); + } + + /* Migrate the page towards the node whose CPU is referencing it */ + if (pol->flags & MPOL_F_MORON) { + int last_nid; + + polnid = numa_node_id(); + + /* + * Multi-stage node selection is used in conjunction + * with a periodic migration fault to build a temporal + * task<->page relation. By using a two-stage filter we + * remove short/unlikely relations. + * + * Using P(p) ~ n_p / n_t as per frequentist + * probability, we can equate a task's usage of a + * particular page (n_p) per total usage of this + * page (n_t) (in a given time-span) to a probability. + * + * Our periodic faults will sample this probability and + * getting the same result twice in a row, given these + * samples are fully independent, is then given by + * P(n)^2, provided our sample period is sufficiently + * short compared to the usage pattern. + * + * This quadric squishes small probabilities, making + * it less likely we act on an unlikely task<->page + * relation. + */ + last_nid = page_xchg_last_nid(page, polnid); + if (last_nid != polnid) + goto out; + } + + if (curnid != polnid) + ret = polnid; +out: + mpol_cond_put(pol); + + return ret; +} + static void sp_delete(struct shared_policy *sp, struct sp_node *n) { pr_debug("deleting %lx-l%lx\n", n->start, n->end); @@ -2305,6 +2486,50 @@ void mpol_free_shared_policy(struct shared_policy *p) mutex_unlock(&p->mutex); } +#ifdef CONFIG_NUMA_BALANCING +static bool __initdata numabalancing_override; + +static void __init check_numabalancing_enable(void) +{ + bool numabalancing_default = false; + + if (IS_ENABLED(CONFIG_NUMA_BALANCING_DEFAULT_ENABLED)) + numabalancing_default = true; + + if (nr_node_ids > 1 && !numabalancing_override) { + printk(KERN_INFO "Enabling automatic NUMA balancing. " + "Configure with numa_balancing= or sysctl"); + set_numabalancing_state(numabalancing_default); + } +} + +static int __init setup_numabalancing(char *str) +{ + int ret = 0; + if (!str) + goto out; + numabalancing_override = true; + + if (!strcmp(str, "enable")) { + set_numabalancing_state(true); + ret = 1; + } else if (!strcmp(str, "disable")) { + set_numabalancing_state(false); + ret = 1; + } +out: + if (!ret) + printk(KERN_WARNING "Unable to parse numa_balancing=\n"); + + return ret; +} +__setup("numa_balancing=", setup_numabalancing); +#else +static inline void __init check_numabalancing_enable(void) +{ +} +#endif /* CONFIG_NUMA_BALANCING */ + /* assumes fs == KERNEL_DS */ void __init numa_policy_init(void) { @@ -2320,6 +2545,15 @@ void __init numa_policy_init(void) sizeof(struct sp_node), 0, SLAB_PANIC, NULL); + for_each_node(nid) { + preferred_node_policy[nid] = (struct mempolicy) { + .refcnt = ATOMIC_INIT(1), + .mode = MPOL_PREFERRED, + .flags = MPOL_F_MOF | MPOL_F_MORON, + .v = { .preferred_node = nid, }, + }; + } + /* * Set interleaving policy for system init. Interleaving is only * enabled across suitably sized nodes (default is >= 16MB), or @@ -2346,6 +2580,8 @@ void __init numa_policy_init(void) if (do_set_mempolicy(MPOL_INTERLEAVE, 0, &interleave_nodes)) printk("numa_policy_init: interleaving failed\n"); + + check_numabalancing_enable(); } /* Reset policy of current process to default */ @@ -2362,14 +2598,13 @@ void numa_default_policy(void) * "local" is pseudo-policy: MPOL_PREFERRED with MPOL_F_LOCAL flag * Used only for mpol_parse_str() and mpol_to_str() */ -#define MPOL_LOCAL MPOL_MAX static const char * const policy_modes[] = { [MPOL_DEFAULT] = "default", [MPOL_PREFERRED] = "prefer", [MPOL_BIND] = "bind", [MPOL_INTERLEAVE] = "interleave", - [MPOL_LOCAL] = "local" + [MPOL_LOCAL] = "local", }; @@ -2415,12 +2650,12 @@ int mpol_parse_str(char *str, struct mempolicy **mpol, int no_context) if (flags) *flags++ = '\0'; /* terminate mode string */ - for (mode = 0; mode <= MPOL_LOCAL; mode++) { + for (mode = 0; mode < MPOL_MAX; mode++) { if (!strcmp(str, policy_modes[mode])) { break; } } - if (mode > MPOL_LOCAL) + if (mode >= MPOL_MAX) goto out; switch (mode) { |