pr_debug("setting mode %d flags %d nodes[0] %lx\n",
mode, flags, nodes ? nodes_addr(*nodes)[0] : -1);
- if (mode == MPOL_DEFAULT) {
+ if (mode == MPOL_DEFAULT || mode == MPOL_NOOP) {
if (nodes && !nodes_empty(*nodes))
return ERR_PTR(-EINVAL);
- return NULL; /* simply delete any existing policy */
+ return NULL;
}
VM_BUG_ON(!nodes);
(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);
pmd = pmd_offset(pud, addr);
do {
next = pmd_addr_end(addr, end);
- split_huge_page_pmd(vma->vm_mm, pmd);
+ split_huge_page_pmd(vma, addr, pmd);
if (pmd_none_or_trans_huge_or_clear_bad(pmd))
continue;
if (check_pte_range(vma, pmd, addr, next, nodes,
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_none(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) {
break;
}
}
+next:
prev = vma;
}
return first;
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;
if (start & ~PAGE_MASK)
return -EINVAL;
- if (mode == MPOL_DEFAULT)
+ if (mode == MPOL_DEFAULT || mode == MPOL_NOOP)
flags &= ~MPOL_MF_STRICT;
len = (len + PAGE_SIZE - 1) & PAGE_MASK;
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
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) && mode != MPOL_NOOP)
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);
+ (unsigned long)vma,
+ false, MIGRATE_SYNC);
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);
unsigned long addr, int node)
{
struct mempolicy *pol;
- struct zonelist *zl;
struct page *page;
unsigned int cpuset_mems_cookie;
return page;
}
- zl = policy_zonelist(gfp, pol, node);
- if (unlikely(mpol_needs_cond_ref(pol))) {
- /*
- * slow path: ref counted shared policy
- */
- struct page *page = __alloc_pages_nodemask(gfp, order,
- zl, policy_nodemask(gfp, pol));
- __mpol_put(pol);
- if (unlikely(!put_mems_allowed(cpuset_mems_cookie) && !page))
- goto retry_cpuset;
- return page;
- }
- /*
- * fast path: default or task policy
- */
- page = __alloc_pages_nodemask(gfp, order, zl,
+ page = __alloc_pages_nodemask(gfp, order,
+ policy_zonelist(gfp, pol, node),
policy_nodemask(gfp, pol));
+ if (unlikely(mpol_needs_cond_ref(pol)))
+ __mpol_put(pol);
if (unlikely(!put_mems_allowed(cpuset_mems_cookie) && !page))
goto retry_cpuset;
return page;
kmem_cache_free(sn_cache, n);
}
+/*
+ * 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 then 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.
+ *
+ * Return the best node ID this page should be on, or -1 if it should
+ * stay where it is.
+ */
+static int
+numa_migration_target(struct page *page, int page_nid,
+ struct task_struct *p, int this_cpu,
+ int cpu_last_access)
+{
+ int nid_last_access;
+ int this_nid;
+
+ if (task_numa_shared(p) < 0)
+ return -1;
+
+ /*
+ * Possibly migrate towards the current node, depends on
+ * task_numa_placement() and access details.
+ */
+ nid_last_access = cpu_to_node(cpu_last_access);
+ this_nid = cpu_to_node(this_cpu);
+
+ if (nid_last_access != this_nid) {
+ /*
+ * 'Access miss': the page got last accessed from a remote node.
+ */
+ return -1;
+ }
+ /*
+ * 'Access hit': the page got last accessed from our node.
+ *
+ * Migrate the page if needed.
+ */
+
+ /* The page is already on this node: */
+ if (page_nid == this_nid)
+ return -1;
+
+ return this_nid;
+}
+
+/**
+ * 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
+ * @multi - use multi-stage node binding
+ *
+ * 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)
+{
+ int best_nid = -1, page_nid;
+ int cpu_last_access, this_cpu;
+ struct mempolicy *pol;
+ unsigned long pgoff;
+ struct zone *zone;
+
+ BUG_ON(!vma);
+
+ this_cpu = raw_smp_processor_id();
+ page_nid = page_to_nid(page);
+
+ cpu_last_access = page_xchg_last_cpu(page, this_cpu);
+
+ pol = get_vma_policy(current, vma, addr);
+ if (!(pol->flags & MPOL_F_MOF) && !(task_numa_shared(current) >= 0))
+ goto out_keep_page;
+
+ 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;
+ best_nid = offset_il_node(pol, vma, pgoff);
+ break;
+
+ case MPOL_PREFERRED:
+ if (pol->flags & MPOL_F_LOCAL)
+ best_nid = numa_node_id();
+ else
+ best_nid = 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(page_nid, pol->v.nodes))
+ goto out_keep_page;
+ (void)first_zones_zonelist(
+ node_zonelist(numa_node_id(), GFP_HIGHUSER),
+ gfp_zone(GFP_HIGHUSER),
+ &pol->v.nodes, &zone);
+ best_nid = zone->node;
+ break;
+
+ default:
+ BUG();
+ }
+
+ best_nid = numa_migration_target(page, page_nid, current, this_cpu, cpu_last_access);
+
+out_keep_page:
+ mpol_cond_put(pol);
+
+ return best_nid;
+}
+
static void sp_delete(struct shared_policy *sp, struct sp_node *n)
{
pr_debug("deleting %lx-l%lx\n", n->start, n->end);
* "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",
+ [MPOL_NOOP] = "noop", /* should not actually be used */
};
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 || mode == MPOL_NOOP)
goto out;
switch (mode) {
projects / karo-tx-linux.git / blobdiff