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-rw-r--r--include/linux/mempolicy.h3
-rw-r--r--mm/mempolicy.c155
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;
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