diff options
| -rw-r--r-- | include/linux/mempolicy.h | 4 | ||||
| -rw-r--r-- | mm/hugetlb.c | 4 | ||||
| -rw-r--r-- | mm/mempolicy.c | 79 |
3 files changed, 75 insertions, 12 deletions
diff --git a/include/linux/mempolicy.h b/include/linux/mempolicy.h index 5bdd656e88c..a020eb2d4e2 100644 --- a/include/linux/mempolicy.h +++ b/include/linux/mempolicy.h @@ -159,7 +159,7 @@ extern void mpol_fix_fork_child_flag(struct task_struct *p); extern struct mempolicy default_policy; extern struct zonelist *huge_zonelist(struct vm_area_struct *vma, - unsigned long addr, gfp_t gfp_flags); + unsigned long addr, gfp_t gfp_flags, struct mempolicy **mpol); extern unsigned slab_node(struct mempolicy *policy); extern enum zone_type policy_zone; @@ -256,7 +256,7 @@ static inline void mpol_fix_fork_child_flag(struct task_struct *p) #define set_cpuset_being_rebound(x) do {} while (0) static inline struct zonelist *huge_zonelist(struct vm_area_struct *vma, - unsigned long addr, gfp_t gfp_flags) + unsigned long addr, gfp_t gfp_flags, struct mempolicy **mpol) { return NODE_DATA(0)->node_zonelists + gfp_zone(gfp_flags); } diff --git a/mm/hugetlb.c b/mm/hugetlb.c index de4cf458d6e..84c795ee2d6 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -71,8 +71,9 @@ static struct page *dequeue_huge_page(struct vm_area_struct *vma, { int nid; struct page *page = NULL; + struct mempolicy *mpol; struct zonelist *zonelist = huge_zonelist(vma, address, - htlb_alloc_mask); + htlb_alloc_mask, &mpol); struct zone **z; for (z = zonelist->zones; *z; z++) { @@ -87,6 +88,7 @@ static struct page *dequeue_huge_page(struct vm_area_struct *vma, break; } } + mpol_free(mpol); /* unref if mpol !NULL */ return page; } diff --git a/mm/mempolicy.c b/mm/mempolicy.c index bb54b88c3d5..3d6ac9505d0 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -1077,21 +1077,37 @@ asmlinkage long compat_sys_mbind(compat_ulong_t start, compat_ulong_t len, #endif -/* Return effective policy for a VMA */ +/* + * get_vma_policy(@task, @vma, @addr) + * @task - task for fallback if vma policy == default + * @vma - virtual memory area whose policy is sought + * @addr - address in @vma for shared policy lookup + * + * Returns effective policy for a VMA at specified address. + * Falls back to @task or system default policy, as necessary. + * Returned policy has extra reference count if shared, vma, + * or some other task's policy [show_numa_maps() can pass + * @task != current]. It is the caller's responsibility to + * free the reference in these cases. + */ static struct mempolicy * get_vma_policy(struct task_struct *task, struct vm_area_struct *vma, unsigned long addr) { struct mempolicy *pol = task->mempolicy; + int shared_pol = 0; if (vma) { - if (vma->vm_ops && vma->vm_ops->get_policy) + if (vma->vm_ops && vma->vm_ops->get_policy) { pol = vma->vm_ops->get_policy(vma, addr); - else if (vma->vm_policy && + shared_pol = 1; /* if pol non-NULL, add ref below */ + } else if (vma->vm_policy && vma->vm_policy->policy != MPOL_DEFAULT) pol = vma->vm_policy; } if (!pol) pol = &default_policy; + else if (!shared_pol && pol != current->mempolicy) + mpol_get(pol); /* vma or other task's policy */ return pol; } @@ -1207,19 +1223,45 @@ static inline unsigned interleave_nid(struct mempolicy *pol, } #ifdef CONFIG_HUGETLBFS -/* Return a zonelist suitable for a huge page allocation. */ +/* + * huge_zonelist(@vma, @addr, @gfp_flags, @mpol) + * @vma = virtual memory area whose policy is sought + * @addr = address in @vma for shared policy lookup and interleave policy + * @gfp_flags = for requested zone + * @mpol = pointer to mempolicy pointer for reference counted 'BIND policy + * + * Returns a zonelist suitable for a huge page allocation. + * If the effective policy is 'BIND, returns pointer to policy's zonelist. + * If it is also a policy for which get_vma_policy() returns an extra + * reference, we must hold that reference until after allocation. + * In that case, return policy via @mpol so hugetlb allocation can drop + * the reference. For non-'BIND referenced policies, we can/do drop the + * reference here, so the caller doesn't need to know about the special case + * for default and current task policy. + */ struct zonelist *huge_zonelist(struct vm_area_struct *vma, unsigned long addr, - gfp_t gfp_flags) + gfp_t gfp_flags, struct mempolicy **mpol) { struct mempolicy *pol = get_vma_policy(current, vma, addr); + struct zonelist *zl; + *mpol = NULL; /* probably no unref needed */ if (pol->policy == MPOL_INTERLEAVE) { unsigned nid; nid = interleave_nid(pol, vma, addr, HPAGE_SHIFT); + __mpol_free(pol); /* finished with pol */ return NODE_DATA(nid)->node_zonelists + gfp_zone(gfp_flags); } - return zonelist_policy(GFP_HIGHUSER, pol); + + zl = zonelist_policy(GFP_HIGHUSER, pol); + if (unlikely(pol != &default_policy && pol != current->mempolicy)) { + if (pol->policy != MPOL_BIND) + __mpol_free(pol); /* finished with pol */ + else + *mpol = pol; /* unref needed after allocation */ + } + return zl; } #endif @@ -1264,6 +1306,7 @@ struct page * alloc_page_vma(gfp_t gfp, struct vm_area_struct *vma, unsigned long addr) { struct mempolicy *pol = get_vma_policy(current, vma, addr); + struct zonelist *zl; cpuset_update_task_memory_state(); @@ -1273,7 +1316,19 @@ alloc_page_vma(gfp_t gfp, struct vm_area_struct *vma, unsigned long addr) nid = interleave_nid(pol, vma, addr, PAGE_SHIFT); return alloc_page_interleave(gfp, 0, nid); } - return __alloc_pages(gfp, 0, zonelist_policy(gfp, pol)); + zl = zonelist_policy(gfp, pol); + if (pol != &default_policy && pol != current->mempolicy) { + /* + * slow path: ref counted policy -- shared or vma + */ + struct page *page = __alloc_pages(gfp, 0, zl); + __mpol_free(pol); + return page; + } + /* + * fast path: default or task policy + */ + return __alloc_pages(gfp, 0, zl); } /** @@ -1872,6 +1927,7 @@ int show_numa_map(struct seq_file *m, void *v) struct numa_maps *md; struct file *file = vma->vm_file; struct mm_struct *mm = vma->vm_mm; + struct mempolicy *pol; int n; char buffer[50]; @@ -1882,8 +1938,13 @@ int show_numa_map(struct seq_file *m, void *v) if (!md) return 0; - mpol_to_str(buffer, sizeof(buffer), - get_vma_policy(priv->task, vma, vma->vm_start)); + pol = get_vma_policy(priv->task, vma, vma->vm_start); + mpol_to_str(buffer, sizeof(buffer), pol); + /* + * unref shared or other task's mempolicy + */ + if (pol != &default_policy && pol != current->mempolicy) + __mpol_free(pol); seq_printf(m, "%08lx %s", vma->vm_start, buffer); |