diff options
| -rw-r--r-- | include/linux/mempolicy.h | 8 | ||||
| -rw-r--r-- | include/uapi/linux/mempolicy.h | 1 | ||||
| -rw-r--r-- | mm/mempolicy.c | 76 |
3 files changed, 85 insertions, 0 deletions
diff --git a/include/linux/mempolicy.h b/include/linux/mempolicy.h index e5ccb9ddd90e..c511e2523560 100644 --- a/include/linux/mempolicy.h +++ b/include/linux/mempolicy.h @@ -198,6 +198,8 @@ static inline int vma_migratable(struct vm_area_struct *vma) return 1; } +extern int mpol_misplaced(struct page *, struct vm_area_struct *, unsigned long); + #else struct mempolicy {}; @@ -323,5 +325,11 @@ static inline int mpol_to_str(char *buffer, int maxlen, struct mempolicy *pol, return 0; } +static inline int mpol_misplaced(struct page *page, struct vm_area_struct *vma, + unsigned long address) +{ + return -1; /* no node preference */ +} + #endif /* CONFIG_NUMA */ #endif diff --git a/include/uapi/linux/mempolicy.h b/include/uapi/linux/mempolicy.h index d23dca8367cc..472de8a5d37e 100644 --- a/include/uapi/linux/mempolicy.h +++ b/include/uapi/linux/mempolicy.h @@ -61,6 +61,7 @@ enum mpol_rebind_step { #define MPOL_F_SHARED (1 << 0) /* identify shared policies */ #define MPOL_F_LOCAL (1 << 1) /* preferred local allocation */ #define MPOL_F_REBINDING (1 << 2) /* identify policies in rebinding */ +#define MPOL_F_MOF (1 << 3) /* this policy wants migrate on fault */ #endif /* _UAPI_LINUX_MEMPOLICY_H */ diff --git a/mm/mempolicy.c b/mm/mempolicy.c index c21e91477c4f..df1466d3d2d8 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -2181,6 +2181,82 @@ 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(); + } + 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); |