diff options
| -rw-r--r-- | include/linux/mempolicy.h | 3 | ||||
| -rw-r--r-- | mm/mempolicy.c | 155 |
2 files changed, 138 insertions, 20 deletions
diff --git a/include/linux/mempolicy.h b/include/linux/mempolicy.h index ed00b27..05443a7 100644 --- a/include/linux/mempolicy.h +++ b/include/linux/mempolicy.h @@ -22,6 +22,9 @@ /* Flags for mbind */ #define MPOL_MF_STRICT (1<<0) /* Verify existing pages in the mapping */ +#define MPOL_MF_MOVE (1<<1) /* Move pages owned by this process to conform to mapping */ +#define MPOL_MF_MOVE_ALL (1<<2) /* Move every page to conform to mapping */ +#define MPOL_MF_INTERNAL (1<<3) /* Internal flags start here */ #ifdef __KERNEL__ diff --git a/mm/mempolicy.c b/mm/mempolicy.c index 0f1d2b8..9cc6d96 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -83,9 +83,14 @@ #include <linux/init.h> #include <linux/compat.h> #include <linux/mempolicy.h> +#include <linux/swap.h> + #include <asm/tlbflush.h> #include <asm/uaccess.h> +/* Internal MPOL_MF_xxx flags */ +#define MPOL_MF_DISCONTIG_OK (MPOL_MF_INTERNAL << 0) /* Skip checks for continuous vmas */ + static kmem_cache_t *policy_cache; static kmem_cache_t *sn_cache; @@ -174,9 +179,59 @@ static struct mempolicy *mpol_new(int mode, nodemask_t *nodes) return policy; } +/* Check if we are the only process mapping the page in question */ +static inline int single_mm_mapping(struct mm_struct *mm, + struct address_space *mapping) +{ + struct vm_area_struct *vma; + struct prio_tree_iter iter; + int rc = 1; + + spin_lock(&mapping->i_mmap_lock); + vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, 0, ULONG_MAX) + if (mm != vma->vm_mm) { + rc = 0; + goto out; + } + list_for_each_entry(vma, &mapping->i_mmap_nonlinear, shared.vm_set.list) + if (mm != vma->vm_mm) { + rc = 0; + goto out; + } +out: + spin_unlock(&mapping->i_mmap_lock); + return rc; +} + +/* + * Add a page to be migrated to the pagelist + */ +static void migrate_page_add(struct vm_area_struct *vma, + struct page *page, struct list_head *pagelist, unsigned long flags) +{ + /* + * Avoid migrating a page that is shared by others and not writable. + */ + if ((flags & MPOL_MF_MOVE_ALL) || !page->mapping || PageAnon(page) || + mapping_writably_mapped(page->mapping) || + single_mm_mapping(vma->vm_mm, page->mapping)) { + int rc = isolate_lru_page(page); + + if (rc == 1) + list_add(&page->lru, pagelist); + /* + * If the isolate attempt was not successful then we just + * encountered an unswappable page. Something must be wrong. + */ + WARN_ON(rc == 0); + } +} + /* Ensure all existing pages follow the policy. */ static int check_pte_range(struct vm_area_struct *vma, pmd_t *pmd, - unsigned long addr, unsigned long end, nodemask_t *nodes) + unsigned long addr, unsigned long end, + const nodemask_t *nodes, unsigned long flags, + struct list_head *pagelist) { pte_t *orig_pte; pte_t *pte; @@ -193,15 +248,21 @@ static int check_pte_range(struct vm_area_struct *vma, pmd_t *pmd, if (!page) continue; nid = page_to_nid(page); - if (!node_isset(nid, *nodes)) - break; + if (!node_isset(nid, *nodes)) { + if (pagelist) + migrate_page_add(vma, page, pagelist, flags); + else + break; + } } while (pte++, addr += PAGE_SIZE, addr != end); pte_unmap_unlock(orig_pte, ptl); return addr != end; } static inline int check_pmd_range(struct vm_area_struct *vma, pud_t *pud, - unsigned long addr, unsigned long end, nodemask_t *nodes) + unsigned long addr, unsigned long end, + const nodemask_t *nodes, unsigned long flags, + struct list_head *pagelist) { pmd_t *pmd; unsigned long next; @@ -211,14 +272,17 @@ static inline int check_pmd_range(struct vm_area_struct *vma, pud_t *pud, next = pmd_addr_end(addr, end); if (pmd_none_or_clear_bad(pmd)) continue; - if (check_pte_range(vma, pmd, addr, next, nodes)) + if (check_pte_range(vma, pmd, addr, next, nodes, + flags, pagelist)) return -EIO; } while (pmd++, addr = next, addr != end); return 0; } static inline int check_pud_range(struct vm_area_struct *vma, pgd_t *pgd, - unsigned long addr, unsigned long end, nodemask_t *nodes) + unsigned long addr, unsigned long end, + const nodemask_t *nodes, unsigned long flags, + struct list_head *pagelist) { pud_t *pud; unsigned long next; @@ -228,14 +292,17 @@ static inline int check_pud_range(struct vm_area_struct *vma, pgd_t *pgd, next = pud_addr_end(addr, end); if (pud_none_or_clear_bad(pud)) continue; - if (check_pmd_range(vma, pud, addr, next, nodes)) + if (check_pmd_range(vma, pud, addr, next, nodes, + flags, pagelist)) return -EIO; } while (pud++, addr = next, addr != end); return 0; } static inline int check_pgd_range(struct vm_area_struct *vma, - unsigned long addr, unsigned long end, nodemask_t *nodes) + unsigned long addr, unsigned long end, + const nodemask_t *nodes, unsigned long flags, + struct list_head *pagelist) { pgd_t *pgd; unsigned long next; @@ -245,16 +312,31 @@ static inline int check_pgd_range(struct vm_area_struct *vma, next = pgd_addr_end(addr, end); if (pgd_none_or_clear_bad(pgd)) continue; - if (check_pud_range(vma, pgd, addr, next, nodes)) + if (check_pud_range(vma, pgd, addr, next, nodes, + flags, pagelist)) return -EIO; } while (pgd++, addr = next, addr != end); return 0; } -/* Step 1: check the range */ +/* Check if a vma is migratable */ +static inline int vma_migratable(struct vm_area_struct *vma) +{ + if (vma->vm_flags & ( + VM_LOCKED|VM_IO|VM_HUGETLB|VM_PFNMAP)) + return 0; + return 1; +} + +/* + * Check if all pages in a range are on a set of nodes. + * If pagelist != NULL then isolate pages from the LRU and + * put them on the pagelist. + */ static struct vm_area_struct * check_range(struct mm_struct *mm, unsigned long start, unsigned long end, - nodemask_t *nodes, unsigned long flags) + const nodemask_t *nodes, unsigned long flags, + struct list_head *pagelist) { int err; struct vm_area_struct *first, *vma, *prev; @@ -264,17 +346,24 @@ 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) { - 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 ((flags & MPOL_MF_STRICT) && !is_vm_hugetlb_page(vma)) { + 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) || + ((flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)) && + vma_migratable(vma)))) { unsigned long endvma = vma->vm_end; + if (endvma > end) endvma = end; if (vma->vm_start > start) start = vma->vm_start; - err = check_pgd_range(vma, start, endvma, nodes); + err = check_pgd_range(vma, start, endvma, nodes, + flags, pagelist); if (err) { first = ERR_PTR(err); break; @@ -348,33 +437,59 @@ long do_mbind(unsigned long start, unsigned long len, struct mempolicy *new; unsigned long end; int err; + LIST_HEAD(pagelist); - if ((flags & ~(unsigned long)(MPOL_MF_STRICT)) || mode > MPOL_MAX) + if ((flags & ~(unsigned long)(MPOL_MF_STRICT|MPOL_MF_MOVE|MPOL_MF_MOVE_ALL)) + || mode > MPOL_MAX) return -EINVAL; + if ((flags & MPOL_MF_MOVE_ALL) && !capable(CAP_SYS_RESOURCE)) + return -EPERM; + if (start & ~PAGE_MASK) return -EINVAL; + if (mode == MPOL_DEFAULT) flags &= ~MPOL_MF_STRICT; + len = (len + PAGE_SIZE - 1) & PAGE_MASK; end = start + len; + if (end < start) return -EINVAL; if (end == start) return 0; + if (mpol_check_policy(mode, nmask)) return -EINVAL; + new = mpol_new(mode, nmask); if (IS_ERR(new)) return PTR_ERR(new); + /* + * If we are using the default policy then operation + * on discontinuous address spaces is okay after all + */ + if (!new) + flags |= MPOL_MF_DISCONTIG_OK; + PDprintk("mbind %lx-%lx mode:%ld nodes:%lx\n",start,start+len, mode,nodes_addr(nodes)[0]); down_write(&mm->mmap_sem); - vma = check_range(mm, start, end, nmask, flags); + vma = check_range(mm, start, end, nmask, flags, + (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)) ? &pagelist : NULL); err = PTR_ERR(vma); - if (!IS_ERR(vma)) + if (!IS_ERR(vma)) { err = mbind_range(vma, start, end, new); + if (!list_empty(&pagelist)) + migrate_pages(&pagelist, NULL); + if (!err && !list_empty(&pagelist) && (flags & MPOL_MF_STRICT)) + err = -EIO; + } + if (!list_empty(&pagelist)) + putback_lru_pages(&pagelist); + up_write(&mm->mmap_sem); mpol_free(new); return err; |
