aboutsummaryrefslogtreecommitdiff
path: root/mm
diff options
context:
space:
mode:
authorJeff Garzik <jgarzik@pobox.com>2005-11-29 03:51:15 -0500
committerJeff Garzik <jgarzik@pobox.com>2005-11-29 03:51:15 -0500
commit4ab432677957e0a064bba3690004d3244de8ad6c (patch)
tree4ef5785f20be6f62bfc7fbe4f124e1751c9cabf5 /mm
parent30765528d156e58d41ed07cae8726c9105111b9d (diff)
parent624f54be206adf970cd8eece16446b027913e533 (diff)
Merge branch 'master'
Diffstat (limited to 'mm')
-rw-r--r--mm/Kconfig6
-rw-r--r--mm/fremap.c28
-rw-r--r--mm/hugetlb.c6
-rw-r--r--mm/madvise.c2
-rw-r--r--mm/memory.c213
-rw-r--r--mm/mempolicy.c12
-rw-r--r--mm/mmap.c11
-rw-r--r--mm/mprotect.c8
-rw-r--r--mm/msync.c12
-rw-r--r--mm/nommu.c2
-rw-r--r--mm/page_alloc.c75
-rw-r--r--mm/rmap.c58
-rw-r--r--mm/swap.c3
-rw-r--r--mm/thrash.c10
-rw-r--r--mm/truncate.c6
-rw-r--r--mm/vmscan.c29
16 files changed, 273 insertions, 208 deletions
diff --git a/mm/Kconfig b/mm/Kconfig
index ae9ce6b73e8..21eb51d4da8 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -125,12 +125,10 @@ comment "Memory hotplug is currently incompatible with Software Suspend"
# space can be handled with less contention: split it at this NR_CPUS.
# Default to 4 for wider testing, though 8 might be more appropriate.
# ARM's adjust_pte (unused if VIPT) depends on mm-wide page_table_lock.
-# PA-RISC's debug spinlock_t is too large for the 32-bit struct page.
-# ARM26 and SPARC32 and PPC64 may use one page for multiple page tables.
+# PA-RISC 7xxx's spinlock_t would enlarge struct page from 32 to 44 bytes.
#
config SPLIT_PTLOCK_CPUS
int
default "4096" if ARM && !CPU_CACHE_VIPT
- default "4096" if PARISC && DEBUG_SPINLOCK && !64BIT
- default "4096" if ARM26 || SPARC32 || PPC64
+ default "4096" if PARISC && !PA20
default "4"
diff --git a/mm/fremap.c b/mm/fremap.c
index d862be3bc3e..f851775e09c 100644
--- a/mm/fremap.c
+++ b/mm/fremap.c
@@ -27,24 +27,20 @@ static int zap_pte(struct mm_struct *mm, struct vm_area_struct *vma,
struct page *page = NULL;
if (pte_present(pte)) {
- unsigned long pfn = pte_pfn(pte);
- flush_cache_page(vma, addr, pfn);
+ flush_cache_page(vma, addr, pte_pfn(pte));
pte = ptep_clear_flush(vma, addr, ptep);
- if (unlikely(!pfn_valid(pfn))) {
- print_bad_pte(vma, pte, addr);
- goto out;
+ page = vm_normal_page(vma, addr, pte);
+ if (page) {
+ if (pte_dirty(pte))
+ set_page_dirty(page);
+ page_remove_rmap(page);
+ page_cache_release(page);
}
- page = pfn_to_page(pfn);
- if (pte_dirty(pte))
- set_page_dirty(page);
- page_remove_rmap(page);
- page_cache_release(page);
} else {
if (!pte_file(pte))
free_swap_and_cache(pte_to_swp_entry(pte));
pte_clear(mm, addr, ptep);
}
-out:
return !!page;
}
@@ -65,8 +61,6 @@ int install_page(struct mm_struct *mm, struct vm_area_struct *vma,
pte_t pte_val;
spinlock_t *ptl;
- BUG_ON(vma->vm_flags & VM_RESERVED);
-
pgd = pgd_offset(mm, addr);
pud = pud_alloc(mm, pgd, addr);
if (!pud)
@@ -122,8 +116,6 @@ int install_file_pte(struct mm_struct *mm, struct vm_area_struct *vma,
pte_t pte_val;
spinlock_t *ptl;
- BUG_ON(vma->vm_flags & VM_RESERVED);
-
pgd = pgd_offset(mm, addr);
pud = pud_alloc(mm, pgd, addr);
if (!pud)
@@ -204,12 +196,10 @@ asmlinkage long sys_remap_file_pages(unsigned long start, unsigned long size,
* Make sure the vma is shared, that it supports prefaulting,
* and that the remapped range is valid and fully within
* the single existing vma. vm_private_data is used as a
- * swapout cursor in a VM_NONLINEAR vma (unless VM_RESERVED
- * or VM_LOCKED, but VM_LOCKED could be revoked later on).
+ * swapout cursor in a VM_NONLINEAR vma.
*/
if (vma && (vma->vm_flags & VM_SHARED) &&
- (!vma->vm_private_data ||
- (vma->vm_flags & (VM_NONLINEAR|VM_RESERVED))) &&
+ (!vma->vm_private_data || (vma->vm_flags & VM_NONLINEAR)) &&
vma->vm_ops && vma->vm_ops->populate &&
end > start && start >= vma->vm_start &&
end <= vma->vm_end) {
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 728e9bda12e..3e52df7c471 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -22,6 +22,10 @@ unsigned long max_huge_pages;
static struct list_head hugepage_freelists[MAX_NUMNODES];
static unsigned int nr_huge_pages_node[MAX_NUMNODES];
static unsigned int free_huge_pages_node[MAX_NUMNODES];
+
+/*
+ * Protects updates to hugepage_freelists, nr_huge_pages, and free_huge_pages
+ */
static DEFINE_SPINLOCK(hugetlb_lock);
static void enqueue_huge_page(struct page *page)
@@ -61,8 +65,10 @@ static struct page *alloc_fresh_huge_page(void)
HUGETLB_PAGE_ORDER);
nid = (nid + 1) % num_online_nodes();
if (page) {
+ spin_lock(&hugetlb_lock);
nr_huge_pages++;
nr_huge_pages_node[page_to_nid(page)]++;
+ spin_unlock(&hugetlb_lock);
}
return page;
}
diff --git a/mm/madvise.c b/mm/madvise.c
index 17aaf3e1644..2b7cf0400a2 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -126,7 +126,7 @@ static long madvise_dontneed(struct vm_area_struct * vma,
unsigned long start, unsigned long end)
{
*prev = vma;
- if (vma->vm_flags & (VM_LOCKED|VM_HUGETLB|VM_RESERVED))
+ if (vma->vm_flags & (VM_LOCKED|VM_HUGETLB|VM_PFNMAP))
return -EINVAL;
if (unlikely(vma->vm_flags & VM_NONLINEAR)) {
diff --git a/mm/memory.c b/mm/memory.c
index 2998cfc12f5..9ab206b829a 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -333,9 +333,9 @@ static inline void add_mm_rss(struct mm_struct *mm, int file_rss, int anon_rss)
}
/*
- * This function is called to print an error when a pte in a
- * !VM_RESERVED region is found pointing to an invalid pfn (which
- * is an error.
+ * This function is called to print an error when a bad pte
+ * is found. For example, we might have a PFN-mapped pte in
+ * a region that doesn't allow it.
*
* The calling function must still handle the error.
*/
@@ -350,6 +350,59 @@ void print_bad_pte(struct vm_area_struct *vma, pte_t pte, unsigned long vaddr)
}
/*
+ * This function gets the "struct page" associated with a pte.
+ *
+ * NOTE! Some mappings do not have "struct pages". A raw PFN mapping
+ * will have each page table entry just pointing to a raw page frame
+ * number, and as far as the VM layer is concerned, those do not have
+ * pages associated with them - even if the PFN might point to memory
+ * that otherwise is perfectly fine and has a "struct page".
+ *
+ * The way we recognize those mappings is through the rules set up
+ * by "remap_pfn_range()": the vma will have the VM_PFNMAP bit set,
+ * and the vm_pgoff will point to the first PFN mapped: thus every
+ * page that is a raw mapping will always honor the rule
+ *
+ * pfn_of_page == vma->vm_pgoff + ((addr - vma->vm_start) >> PAGE_SHIFT)
+ *
+ * and if that isn't true, the page has been COW'ed (in which case it
+ * _does_ have a "struct page" associated with it even if it is in a
+ * VM_PFNMAP range).
+ */
+struct page *vm_normal_page(struct vm_area_struct *vma, unsigned long addr, pte_t pte)
+{
+ unsigned long pfn = pte_pfn(pte);
+
+ if (vma->vm_flags & VM_PFNMAP) {
+ unsigned long off = (addr - vma->vm_start) >> PAGE_SHIFT;
+ if (pfn == vma->vm_pgoff + off)
+ return NULL;
+ }
+
+ /*
+ * Add some anal sanity checks for now. Eventually,
+ * we should just do "return pfn_to_page(pfn)", but
+ * in the meantime we check that we get a valid pfn,
+ * and that the resulting page looks ok.
+ *
+ * Remove this test eventually!
+ */
+ if (unlikely(!pfn_valid(pfn))) {
+ print_bad_pte(vma, pte, addr);
+ return NULL;
+ }
+
+ /*
+ * NOTE! We still have PageReserved() pages in the page
+ * tables.
+ *
+ * The PAGE_ZERO() pages and various VDSO mappings can
+ * cause them to exist.
+ */
+ return pfn_to_page(pfn);
+}
+
+/*
* copy one vm_area from one task to the other. Assumes the page tables
* already present in the new task to be cleared in the whole range
* covered by this vma.
@@ -363,7 +416,6 @@ copy_one_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm,
unsigned long vm_flags = vma->vm_flags;
pte_t pte = *src_pte;
struct page *page;
- unsigned long pfn;
/* pte contains position in swap or file, so copy. */
if (unlikely(!pte_present(pte))) {
@@ -381,23 +433,6 @@ copy_one_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm,
goto out_set_pte;
}
- /* If the region is VM_RESERVED, the mapping is not
- * mapped via rmap - duplicate the pte as is.
- */
- if (vm_flags & VM_RESERVED)
- goto out_set_pte;
-
- pfn = pte_pfn(pte);
- /* If the pte points outside of valid memory but
- * the region is not VM_RESERVED, we have a problem.
- */
- if (unlikely(!pfn_valid(pfn))) {
- print_bad_pte(vma, pte, addr);
- goto out_set_pte; /* try to do something sane */
- }
-
- page = pfn_to_page(pfn);
-
/*
* If it's a COW mapping, write protect it both
* in the parent and the child
@@ -414,9 +449,13 @@ copy_one_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm,
if (vm_flags & VM_SHARED)
pte = pte_mkclean(pte);
pte = pte_mkold(pte);
- get_page(page);
- page_dup_rmap(page);
- rss[!!PageAnon(page)]++;
+
+ page = vm_normal_page(vma, addr, pte);
+ if (page) {
+ get_page(page);
+ page_dup_rmap(page);
+ rss[!!PageAnon(page)]++;
+ }
out_set_pte:
set_pte_at(dst_mm, addr, dst_pte, pte);
@@ -528,7 +567,7 @@ int copy_page_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
* readonly mappings. The tradeoff is that copy_page_range is more
* efficient than faulting.
*/
- if (!(vma->vm_flags & (VM_HUGETLB|VM_NONLINEAR|VM_RESERVED))) {
+ if (!(vma->vm_flags & (VM_HUGETLB|VM_NONLINEAR|VM_PFNMAP))) {
if (!vma->anon_vma)
return 0;
}
@@ -568,17 +607,11 @@ static unsigned long zap_pte_range(struct mmu_gather *tlb,
continue;
}
if (pte_present(ptent)) {
- struct page *page = NULL;
+ struct page *page;
(*zap_work) -= PAGE_SIZE;
- if (!(vma->vm_flags & VM_RESERVED)) {
- unsigned long pfn = pte_pfn(ptent);
- if (unlikely(!pfn_valid(pfn)))
- print_bad_pte(vma, ptent, addr);
- else
- page = pfn_to_page(pfn);
- }
+ page = vm_normal_page(vma, addr, ptent);
if (unlikely(details) && page) {
/*
* unmap_shared_mapping_pages() wants to
@@ -834,7 +867,7 @@ unsigned long zap_page_range(struct vm_area_struct *vma, unsigned long address,
/*
* Do a quick page-table lookup for a single page.
*/
-struct page *follow_page(struct mm_struct *mm, unsigned long address,
+struct page *follow_page(struct vm_area_struct *vma, unsigned long address,
unsigned int flags)
{
pgd_t *pgd;
@@ -842,8 +875,8 @@ struct page *follow_page(struct mm_struct *mm, unsigned long address,
pmd_t *pmd;
pte_t *ptep, pte;
spinlock_t *ptl;
- unsigned long pfn;
struct page *page;
+ struct mm_struct *mm = vma->vm_mm;
page = follow_huge_addr(mm, address, flags & FOLL_WRITE);
if (!IS_ERR(page)) {
@@ -879,11 +912,10 @@ struct page *follow_page(struct mm_struct *mm, unsigned long address,
goto unlock;
if ((flags & FOLL_WRITE) && !pte_write(pte))
goto unlock;
- pfn = pte_pfn(pte);
- if (!pfn_valid(pfn))
+ page = vm_normal_page(vma, address, pte);
+ if (unlikely(!page))
goto unlock;
- page = pfn_to_page(pfn);
if (flags & FOLL_GET)
get_page(page);
if (flags & FOLL_TOUCH) {
@@ -956,8 +988,10 @@ int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
return i ? : -EFAULT;
}
if (pages) {
- pages[i] = pte_page(*pte);
- get_page(pages[i]);
+ struct page *page = vm_normal_page(vma, start, *pte);
+ pages[i] = page;
+ if (page)
+ get_page(page);
}
pte_unmap(pte);
if (vmas)
@@ -968,7 +1002,7 @@ int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
continue;
}
- if (!vma || (vma->vm_flags & (VM_IO | VM_RESERVED))
+ if (!vma || (vma->vm_flags & VM_IO)
|| !(vm_flags & vma->vm_flags))
return i ? : -EFAULT;
@@ -992,7 +1026,7 @@ int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
foll_flags |= FOLL_WRITE;
cond_resched();
- while (!(page = follow_page(mm, start, foll_flags))) {
+ while (!(page = follow_page(vma, start, foll_flags))) {
int ret;
ret = __handle_mm_fault(mm, vma, start,
foll_flags & FOLL_WRITE);
@@ -1191,10 +1225,17 @@ int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr,
* rest of the world about it:
* VM_IO tells people not to look at these pages
* (accesses can have side effects).
- * VM_RESERVED tells the core MM not to "manage" these pages
- * (e.g. refcount, mapcount, try to swap them out).
+ * VM_RESERVED is specified all over the place, because
+ * in 2.4 it kept swapout's vma scan off this vma; but
+ * in 2.6 the LRU scan won't even find its pages, so this
+ * flag means no more than count its pages in reserved_vm,
+ * and omit it from core dump, even when VM_IO turned off.
+ * VM_PFNMAP tells the core MM that the base pages are just
+ * raw PFN mappings, and do not have a "struct page" associated
+ * with them.
*/
- vma->vm_flags |= VM_IO | VM_RESERVED;
+ vma->vm_flags |= VM_IO | VM_RESERVED | VM_PFNMAP;
+ vma->vm_pgoff = pfn;
BUG_ON(addr >= end);
pfn -= addr >> PAGE_SHIFT;
@@ -1249,6 +1290,26 @@ static inline pte_t maybe_mkwrite(pte_t pte, struct vm_area_struct *vma)
return pte;
}
+static inline void cow_user_page(struct page *dst, struct page *src, unsigned long va)
+{
+ /*
+ * If the source page was a PFN mapping, we don't have
+ * a "struct page" for it. We do a best-effort copy by
+ * just copying from the original user address. If that
+ * fails, we just zero-fill it. Live with it.
+ */
+ if (unlikely(!src)) {
+ void *kaddr = kmap_atomic(dst, KM_USER0);
+ unsigned long left = __copy_from_user_inatomic(kaddr, (void __user *)va, PAGE_SIZE);
+ if (left)
+ memset(kaddr, 0, PAGE_SIZE);
+ kunmap_atomic(kaddr, KM_USER0);
+ return;
+
+ }
+ copy_user_highpage(dst, src, va);
+}
+
/*
* This routine handles present pages, when users try to write
* to a shared page. It is done by copying the page to a new address
@@ -1271,22 +1332,14 @@ static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
unsigned long address, pte_t *page_table, pmd_t *pmd,
spinlock_t *ptl, pte_t orig_pte)
{
- struct page *old_page, *new_page;
- unsigned long pfn = pte_pfn(orig_pte);
+ struct page *old_page, *src_page, *new_page;
pte_t entry;
int ret = VM_FAULT_MINOR;
- BUG_ON(vma->vm_flags & VM_RESERVED);
-
- if (unlikely(!pfn_valid(pfn))) {
- /*
- * Page table corrupted: show pte and kill process.
- */
- print_bad_pte(vma, orig_pte, address);
- ret = VM_FAULT_OOM;
- goto unlock;
- }
- old_page = pfn_to_page(pfn);
+ old_page = vm_normal_page(vma, address, orig_pte);
+ src_page = old_page;
+ if (!old_page)
+ goto gotten;
if (PageAnon(old_page) && !TestSetPageLocked(old_page)) {
int reuse = can_share_swap_page(old_page);
@@ -1307,11 +1360,12 @@ static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
* Ok, we need to copy. Oh, well..
*/
page_cache_get(old_page);
+gotten:
pte_unmap_unlock(page_table, ptl);
if (unlikely(anon_vma_prepare(vma)))
goto oom;
- if (old_page == ZERO_PAGE(address)) {
+ if (src_page == ZERO_PAGE(address)) {
new_page = alloc_zeroed_user_highpage(vma, address);
if (!new_page)
goto oom;
@@ -1319,7 +1373,7 @@ static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
new_page = alloc_page_vma(GFP_HIGHUSER, vma, address);
if (!new_page)
goto oom;
- copy_user_highpage(new_page, old_page, address);
+ cow_user_page(new_page, src_page, address);
}
/*
@@ -1327,11 +1381,14 @@ static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
*/
page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
if (likely(pte_same(*page_table, orig_pte))) {
- page_remove_rmap(old_page);
- if (!PageAnon(old_page)) {
+ if (old_page) {
+ page_remove_rmap(old_page);
+ if (!PageAnon(old_page)) {
+ dec_mm_counter(mm, file_rss);
+ inc_mm_counter(mm, anon_rss);
+ }
+ } else
inc_mm_counter(mm, anon_rss);
- dec_mm_counter(mm, file_rss);
- }
flush_cache_page(vma, address, pfn);
entry = mk_pte(new_page, vma->vm_page_prot);
entry = maybe_mkwrite(pte_mkdirty(entry), vma);
@@ -1345,13 +1402,16 @@ static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
new_page = old_page;
ret |= VM_FAULT_WRITE;
}
- page_cache_release(new_page);
- page_cache_release(old_page);
+ if (new_page)
+ page_cache_release(new_page);
+ if (old_page)
+ page_cache_release(old_page);
unlock:
pte_unmap_unlock(page_table, ptl);
return ret;
oom:
- page_cache_release(old_page);
+ if (old_page)
+ page_cache_release(old_page);
return VM_FAULT_OOM;
}
@@ -1849,7 +1909,6 @@ static int do_no_page(struct mm_struct *mm, struct vm_area_struct *vma,
int anon = 0;
pte_unmap(page_table);
-
if (vma->vm_file) {
mapping = vma->vm_file->f_mapping;
sequence = mapping->truncate_count;
@@ -1882,7 +1941,7 @@ retry:
page = alloc_page_vma(GFP_HIGHUSER, vma, address);
if (!page)
goto oom;
- copy_user_highpage(page, new_page, address);
+ cow_user_page(page, new_page, address);
page_cache_release(new_page);
new_page = page;
anon = 1;
@@ -1924,7 +1983,7 @@ retry:
inc_mm_counter(mm, anon_rss);
lru_cache_add_active(new_page);
page_add_anon_rmap(new_page, vma, address);
- } else if (!(vma->vm_flags & VM_RESERVED)) {
+ } else {
inc_mm_counter(mm, file_rss);
page_add_file_rmap(new_page);
}
@@ -2101,6 +2160,12 @@ int __pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address)
spin_unlock(&mm->page_table_lock);
return 0;
}
+#else
+/* Workaround for gcc 2.96 */
+int __pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address)
+{
+ return 0;
+}
#endif /* __PAGETABLE_PUD_FOLDED */
#ifndef __PAGETABLE_PMD_FOLDED
@@ -2129,6 +2194,12 @@ int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address)
spin_unlock(&mm->page_table_lock);
return 0;
}
+#else
+/* Workaround for gcc 2.96 */
+int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address)
+{
+ return 0;
+}
#endif /* __PAGETABLE_PMD_FOLDED */
int make_pages_present(unsigned long addr, unsigned long end)
@@ -2203,7 +2274,7 @@ static int __init gate_vma_init(void)
gate_vma.vm_start = FIXADDR_USER_START;
gate_vma.vm_end = FIXADDR_USER_END;
gate_vma.vm_page_prot = PAGE_READONLY;
- gate_vma.vm_flags = VM_RESERVED;
+ gate_vma.vm_flags = 0;
return 0;
}
__initcall(gate_vma_init);
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 5abc57c2b8b..bec88c81244 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -189,17 +189,15 @@ static int check_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
orig_pte = pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
do {
- unsigned long pfn;
+ struct page *page;
unsigned int nid;
if (!pte_present(*pte))
continue;
- pfn = pte_pfn(*pte);
- if (!pfn_valid(pfn)) {
- print_bad_pte(vma, *pte, addr);
+ page = vm_normal_page(vma, addr, *pte);
+ if (!page)
continue;
- }
- nid = pfn_to_nid(pfn);
+ nid = page_to_nid(page);
if (!node_isset(nid, *nodes))
break;
} while (pte++, addr += PAGE_SIZE, addr != end);
@@ -269,8 +267,6 @@ check_range(struct mm_struct *mm, unsigned long start, unsigned long end,
first = find_vma(mm, start);
if (!first)
return ERR_PTR(-EFAULT);
- if (first->vm_flags & VM_RESERVED)
- return ERR_PTR(-EACCES);
prev = NULL;
for (vma = first; vma && vma->vm_start < end; vma = vma->vm_next) {
if (!vma->vm_next && vma->vm_end < end)
diff --git a/mm/mmap.c b/mm/mmap.c
index 4f8def03428..11ca5927d5f 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1076,17 +1076,6 @@ munmap_back:
error = file->f_op->mmap(file, vma);
if (error)
goto unmap_and_free_vma;
- if ((vma->vm_flags & (VM_SHARED | VM_WRITE | VM_RESERVED))
- == (VM_WRITE | VM_RESERVED)) {
- printk(KERN_WARNING "program %s is using MAP_PRIVATE, "
- "PROT_WRITE mmap of VM_RESERVED memory, which "
- "is deprecated. Please report this to "
- "linux-kernel@vger.kernel.org\n",current->comm);
- if (vma->vm_ops && vma->vm_ops->close)
- vma->vm_ops->close(vma);
- error = -EACCES;
- goto unmap_and_free_vma;
- }
} else if (vm_flags & VM_SHARED) {
error = shmem_zero_setup(vma);
if (error)
diff --git a/mm/mprotect.c b/mm/mprotect.c
index 17a2b52b753..653b8571c1e 100644
--- a/mm/mprotect.c
+++ b/mm/mprotect.c
@@ -124,14 +124,6 @@ mprotect_fixup(struct vm_area_struct *vma, struct vm_area_struct **pprev,
* a MAP_NORESERVE private mapping to writable will now reserve.
*/
if (newflags & VM_WRITE) {
- if (oldflags & VM_RESERVED) {
- BUG_ON(oldflags & VM_WRITE);
- printk(KERN_WARNING "program %s is using MAP_PRIVATE, "
- "PROT_WRITE mprotect of VM_RESERVED memory, "
- "which is deprecated. Please report this to "
- "linux-kernel@vger.kernel.org\n",current->comm);
- return -EACCES;
- }
if (!(oldflags & (VM_ACCOUNT|VM_WRITE|VM_SHARED|VM_HUGETLB))) {
charged = nrpages;
if (security_vm_enough_memory(charged))
diff --git a/mm/msync.c b/mm/msync.c
index 0e040e9c39d..1b5b6f662dc 100644
--- a/mm/msync.c
+++ b/mm/msync.c
@@ -27,7 +27,6 @@ static void msync_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
again:
pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
do {
- unsigned long pfn;
struct page *page;
if (progress >= 64) {
@@ -40,13 +39,9 @@ again:
continue;
if (!pte_maybe_dirty(*pte))
continue;
- pfn = pte_pfn(*pte);
- if (unlikely(!pfn_valid(pfn))) {
- print_bad_pte(vma, *pte, addr);
+ page = vm_normal_page(vma, addr, *pte);
+ if (!page)
continue;
- }
- page = pfn_to_page(pfn);
-
if (ptep_clear_flush_dirty(vma, addr, pte) ||
page_test_and_clear_dirty(page))
set_page_dirty(page);
@@ -97,9 +92,8 @@ static void msync_page_range(struct vm_area_struct *vma,
/* For hugepages we can't go walking the page table normally,
* but that's ok, hugetlbfs is memory based, so we don't need
* to do anything more on an msync().
- * Can't do anything with VM_RESERVED regions either.
*/
- if (vma->vm_flags & (VM_HUGETLB|VM_RESERVED))
+ if (vma->vm_flags & VM_HUGETLB)
return;
BUG_ON(addr >= end);
diff --git a/mm/nommu.c b/mm/nommu.c
index 6deb6ab3d6a..c1196812876 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -1045,7 +1045,7 @@ struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr)
EXPORT_SYMBOL(find_vma);
-struct page *follow_page(struct mm_struct *mm, unsigned long address,
+struct page *follow_page(struct vm_area_struct *vma, unsigned long address,
unsigned int foll_flags)
{
return NULL;
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index bd4de592dc2..b257720edfc 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -140,18 +140,13 @@ static void bad_page(const char *function, struct page *page)
1 << PG_reclaim |
1 << PG_slab |
1 << PG_swapcache |
- 1 << PG_writeback |
- 1 << PG_reserved );
+ 1 << PG_writeback );
set_page_count(page, 0);
reset_page_mapcount(page);
page->mapping = NULL;
add_taint(TAINT_BAD_PAGE);
}
-#ifndef CONFIG_HUGETLB_PAGE
-#define prep_compound_page(page, order) do { } while (0)
-#define destroy_compound_page(page, order) do { } while (0)
-#else
/*
* Higher-order pages are called "compound pages". They are structured thusly:
*
@@ -205,7 +200,6 @@ static void destroy_compound_page(struct page *page, unsigned long order)
ClearPageCompound(p);
}
}
-#endif /* CONFIG_HUGETLB_PAGE */
/*
* function for dealing with page's order in buddy system.
@@ -340,7 +334,7 @@ static inline void __free_pages_bulk (struct page *page,
zone->free_area[order].nr_free++;
}
-static inline void free_pages_check(const char *function, struct page *page)
+static inline int free_pages_check(const char *function, struct page *page)
{
if ( page_mapcount(page) ||
page->mapping != NULL ||
@@ -358,6 +352,12 @@ static inline void free_pages_check(const char *function, struct page *page)
bad_page(function, page);
if (PageDirty(page))
__ClearPageDirty(page);
+ /*
+ * For now, we report if PG_reserved was found set, but do not
+ * clear it, and do not free the page. But we shall soon need
+ * to do more, for when the ZERO_PAGE count wraps negative.
+ */
+ return PageReserved(page);
}
/*
@@ -397,11 +397,10 @@ void __free_pages_ok(struct page *page, unsigned int order)
{
LIST_HEAD(list);
int i;
+ int reserved = 0;
arch_free_page(page, order);
- mod_page_state(pgfree, 1 << order);
-
#ifndef CONFIG_MMU
if (order > 0)
for (i = 1 ; i < (1 << order) ; ++i)
@@ -409,8 +408,12 @@ void __free_pages_ok(struct page *page, unsigned int order)
#endif
for (i = 0 ; i < (1 << order) ; ++i)
- free_pages_check(__FUNCTION__, page + i);
+ reserved += free_pages_check(__FUNCTION__, page + i);
+ if (reserved)
+ return;
+
list_add(&page->lru, &list);
+ mod_page_state(pgfree, 1 << order);
kernel_map_pages(page, 1<<order, 0);
free_pages_bulk(page_zone(page), 1, &list, order);
}
@@ -468,7 +471,7 @@ void set_page_refs(struct page *page, int order)
/*
* This page is about to be returned from the page allocator
*/
-static void prep_new_page(struct page *page, int order)
+static int prep_new_page(struct page *page, int order)
{
if ( page_mapcount(page) ||
page->mapping != NULL ||
@@ -486,12 +489,20 @@ static void prep_new_page(struct page *page, int order)
1 << PG_reserved )))
bad_page(__FUNCTION__, page);
+ /*
+ * For now, we report if PG_reserved was found set, but do not
+ * clear it, and do not allocate the page: as a safety net.
+ */
+ if (PageReserved(page))
+ return 1;
+
page->flags &= ~(1 << PG_uptodate | 1 << PG_error |
1 << PG_referenced | 1 << PG_arch_1 |
1 << PG_checked | 1 << PG_mappedtodisk);
set_page_private(page, 0);
set_page_refs(page, order);
kernel_map_pages(page, 1 << order, 1);
+ return 0;
}
/*
@@ -674,11 +685,14 @@ static void fastcall free_hot_cold_page(struct page *page, int cold)
arch_free_page(page, 0);
- kernel_map_pages(page, 1, 0);
- inc_page_state(pgfree);
if (PageAnon(page))
page->mapping = NULL;
- free_pages_check(__FUNCTION__, page);
+ if (free_pages_check(__FUNCTION__, page))
+ return;
+
+ inc_page_state(pgfree);
+ kernel_map_pages(page, 1, 0);
+
pcp = &zone_pcp(zone, get_cpu())->pcp[cold];
local_irq_save(flags);
list_add(&page->lru, &pcp->list);
@@ -717,12 +731,14 @@ static struct page *
buffered_rmqueue(struct zone *zone, int order, gfp_t gfp_flags)
{
unsigned long flags;
- struct page *page = NULL;
+ struct page *page;
int cold = !!(gfp_flags & __GFP_COLD);
+again:
if (order == 0) {
struct per_cpu_pages *pcp;
+ page = NULL;
pcp = &zone_pcp(zone, get_cpu())->pcp[cold];
local_irq_save(flags);
if (pcp->count <= pcp->low)
@@ -744,7 +760,8 @@ buffered_rmqueue(struct zone *zone, int order, gfp_t gfp_flags)
if (page != NULL) {
BUG_ON(bad_range(zone, page));
mod_page_state_zone(zone, pgalloc, 1 << order);
- prep_new_page(page, order);
+ if (prep_new_page(page, order))
+ goto again;
if (gfp_flags & __GFP_ZERO)
prep_zero_page(page, order, gfp_flags);
@@ -756,9 +773,12 @@ buffered_rmqueue(struct zone *zone, int order, gfp_t gfp_flags)
}
#define ALLOC_NO_WATERMARKS 0x01 /* don't check watermarks at all */
-#define ALLOC_HARDER 0x02 /* try to alloc harder */
-#define ALLOC_HIGH 0x04 /* __GFP_HIGH set */
-#define ALLOC_CPUSET 0x08 /* check for correct cpuset */
+#define ALLOC_WMARK_MIN 0x02 /* use pages_min watermark */
+#define ALLOC_WMARK_LOW 0x04 /* use pages_low watermark */
+#define ALLOC_WMARK_HIGH 0x08 /* use pages_high watermark */
+#define ALLOC_HARDER 0x10 /* try to alloc harder */
+#define ALLOC_HIGH 0x20 /* __GFP_HIGH set */
+#define ALLOC_CPUSET 0x40 /* check for correct cpuset */
/*
* Return 1 if free pages are above 'mark'. This takes into account the order
@@ -813,7 +833,14 @@ get_page_from_freelist(gfp_t gfp_mask, unsigned int order,
continue;
if (!(alloc_flags & ALLOC_NO_WATERMARKS)) {
- if (!zone_watermark_ok(*z, order, (*z)->pages_low,
+ unsigned long mark;
+ if (alloc_flags & ALLOC_WMARK_MIN)
+ mark = (*z)->pages_min;
+ else if (alloc_flags & ALLOC_WMARK_LOW)
+ mark = (*z)->pages_low;
+ else
+ mark = (*z)->pages_high;
+ if (!zone_watermark_ok(*z, order, mark,
classzone_idx, alloc_flags))
continue;
}
@@ -854,7 +881,7 @@ restart:
}
page = get_page_from_freelist(gfp_mask|__GFP_HARDWALL, order,
- zonelist, ALLOC_CPUSET);
+ zonelist, ALLOC_WMARK_LOW|ALLOC_CPUSET);
if (page)
goto got_pg;
@@ -871,7 +898,7 @@ restart:
* cannot run direct reclaim, or if the caller has realtime scheduling
* policy.
*/
- alloc_flags = 0;
+ alloc_flags = ALLOC_WMARK_MIN;
if ((unlikely(rt_task(p)) && !in_interrupt()) || !wait)
alloc_flags |= ALLOC_HARDER;
if (gfp_mask & __GFP_HIGH)
@@ -942,7 +969,7 @@ rebalance:
* under heavy pressure.
*/
page = get_page_from_freelist(gfp_mask|__GFP_HARDWALL, order,
- zonelist, ALLOC_CPUSET);
+ zonelist, ALLOC_WMARK_HIGH|ALLOC_CPUSET);
if (page)
goto got_pg;
diff --git a/mm/rmap.c b/mm/rmap.c
index 914d04b98be..491ac350048 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -225,7 +225,7 @@ vma_address(struct page *page, struct vm_area_struct *vma)
/*
* At what user virtual address is page expected in vma? checking that the
- * page matches the vma: currently only used by unuse_process, on anon pages.
+ * page matches the vma: currently only used on anon pages, by unuse_vma;
*/
unsigned long page_address_in_vma(struct page *page, struct vm_area_struct *vma)
{
@@ -234,7 +234,8 @@ unsigned long page_address_in_vma(struct page *page, struct vm_area_struct *vma)
(void *)page->mapping - PAGE_MAPPING_ANON)
return -EFAULT;
} else if (page->mapping && !(vma->vm_flags & VM_NONLINEAR)) {
- if (vma->vm_file->f_mapping != page->mapping)
+ if (!vma->vm_file ||
+ vma->vm_file->f_mapping != page->mapping)
return -EFAULT;
} else
return -EFAULT;
@@ -289,7 +290,7 @@ pte_t *page_check_address(struct page *page, struct mm_struct *mm,
* repeatedly from either page_referenced_anon or page_referenced_file.
*/
static int page_referenced_one(struct page *page,
- struct vm_area_struct *vma, unsigned int *mapcount, int ignore_token)
+ struct vm_area_struct *vma, unsigned int *mapcount)
{
struct mm_struct *mm = vma->vm_mm;
unsigned long address;
@@ -310,7 +311,7 @@ static int page_referenced_one(struct page *page,
/* Pretend the page is referenced if the task has the
swap token and is in the middle of a page fault. */
- if (mm != current->mm && !ignore_token && has_swap_token(mm) &&
+ if (mm != current->mm && has_swap_token(mm) &&
rwsem_is_locked(&mm->mmap_sem))
referenced++;
@@ -320,7 +321,7 @@ out:
return referenced;
}
-static int page_referenced_anon(struct page *page, int ignore_token)
+static int page_referenced_anon(struct page *page)
{
unsigned int mapcount;
struct anon_vma *anon_vma;
@@ -333,8 +334,7 @@ static int page_referenced_anon(struct page *page, int ignore_token)
mapcount = page_mapcount(page);
list_for_each_entry(vma, &anon_vma->head, anon_vma_node) {
- referenced += page_referenced_one(page, vma, &mapcount,
- ignore_token);
+ referenced += page_referenced_one(page, vma, &mapcount);
if (!mapcount)
break;
}
@@ -353,7 +353,7 @@ static int page_referenced_anon(struct page *page, int ignore_token)
*
* This function is only called from page_referenced for object-based pages.
*/
-static int page_referenced_file(struct page *page, int ignore_token)
+static int page_referenced_file(struct page *page)
{
unsigned int mapcount;
struct address_space *mapping = page->mapping;
@@ -391,8 +391,7 @@ static int page_referenced_file(struct page *page, int ignore_token)
referenced++;
break;
}
- referenced += page_referenced_one(page, vma, &mapcount,
- ignore_token);
+ referenced += page_referenced_one(page, vma, &mapcount);
if (!mapcount)
break;
}
@@ -409,13 +408,10 @@ static int page_referenced_file(struct page *page, int ignore_token)
* Quick test_and_clear_referenced for all mappings to a page,
* returns the number of ptes which referenced the page.
*/
-int page_referenced(struct page *page, int is_locked, int ignore_token)
+int page_referenced(struct page *page, int is_locked)
{
int referenced = 0;
- if (!swap_token_default_timeout)
- ignore_token = 1;
-
if (page_test_and_clear_young(page))
referenced++;
@@ -424,15 +420,14 @@ int page_referenced(struct page *page, int is_locked, int ignore_token)
if (page_mapped(page) && page->mapping) {
if (PageAnon(page))
- referenced += page_referenced_anon(page, ignore_token);
+ referenced += page_referenced_anon(page);
else if (is_locked)
- referenced += page_referenced_file(page, ignore_token);
+ referenced += page_referenced_file(page);
else if (TestSetPageLocked(page))
referenced++;
else {
if (page->mapping)
- referenced += page_referenced_file(page,
- ignore_token);
+ referenced += page_referenced_file(page);
unlock_page(page);
}
}
@@ -529,10 +524,8 @@ static int try_to_unmap_one(struct page *page, struct vm_area_struct *vma)
* If the page is mlock()d, we cannot swap it out.
* If it's recently referenced (perhaps page_referenced
* skipped over this mm) then we should reactivate it.
- *
- * Pages belonging to VM_RESERVED regions should not happen here.
*/
- if ((vma->vm_flags & (VM_LOCKED|VM_RESERVED)) ||
+ if ((vma->vm_flags & VM_LOCKED) ||
ptep_clear_flush_young(vma, address, pte)) {
ret = SWAP_FAIL;
goto out_unmap;
@@ -613,7 +606,6 @@ static void try_to_unmap_cluster(unsigned long cursor,
struct page *page;
unsigned long address;
unsigned long end;
- unsigned long pfn;
address = (vma->vm_start + cursor) & CLUSTER_MASK;
end = address + CLUSTER_SIZE;
@@ -642,15 +634,8 @@ static void try_to_unmap_cluster(unsigned long cursor,
for (; address < end; pte++, address += PAGE_SIZE) {
if (!pte_present(*pte))
continue;
-
- pfn = pte_pfn(*pte);
- if (unlikely(!pfn_valid(pfn))) {
- print_bad_pte(vma, *pte, address);
- continue;
- }
-
- page = pfn_to_page(pfn);
- BUG_ON(PageAnon(page));
+ page = vm_normal_page(vma, address, *pte);
+ BUG_ON(!page || PageAnon(page));
if (ptep_clear_flush_young(vma, address, pte))
continue;
@@ -727,7 +712,7 @@ static int try_to_unmap_file(struct page *page)
list_for_each_entry(vma, &mapping->i_mmap_nonlinear,
shared.vm_set.list) {
- if (vma->vm_flags & (VM_LOCKED|VM_RESERVED))
+ if (vma->vm_flags & VM_LOCKED)
continue;
cursor = (unsigned long) vma->vm_private_data;
if (cursor > max_nl_cursor)
@@ -761,7 +746,7 @@ static int try_to_unmap_file(struct page *page)
do {
list_for_each_entry(vma, &mapping->i_mmap_nonlinear,
shared.vm_set.list) {
- if (vma->vm_flags & (VM_LOCKED|VM_RESERVED))
+ if (vma->vm_flags & VM_LOCKED)
continue;
cursor = (unsigned long) vma->vm_private_data;
while ( cursor < max_nl_cursor &&
@@ -783,11 +768,8 @@ static int try_to_unmap_file(struct page *page)
* in locked vmas). Reset cursor on all unreserved nonlinear
* vmas, now forgetting on which ones it had fallen behind.
*/
- list_for_each_entry(vma, &mapping->i_mmap_nonlinear,
- shared.vm_set.list) {
- if (!(vma->vm_flags & VM_RESERVED))
- vma->vm_private_data = NULL;
- }
+ list_for_each_entry(vma, &mapping->i_mmap_nonlinear, shared.vm_set.list)
+ vma->vm_private_data = NULL;
out:
spin_unlock(&mapping->i_mmap_lock);
return ret;
diff --git a/mm/swap.c b/mm/swap.c
index d09cf7f03e7..73d351439ef 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -34,8 +34,6 @@
/* How many pages do we try to swap or page in/out together? */
int page_cluster;
-#ifdef CONFIG_HUGETLB_PAGE
-
void put_page(struct page *page)
{
if (unlikely(PageCompound(page))) {
@@ -52,7 +50,6 @@ void put_page(struct page *page)
__page_cache_release(page);
}
EXPORT_SYMBOL(put_page);
-#endif
/*
* Writeback is about to end against a page which has been marked for immediate
diff --git a/mm/thrash.c b/mm/thrash.c
index eff3c18c33a..f4c560b4a2b 100644
--- a/mm/thrash.c
+++ b/mm/thrash.c
@@ -57,14 +57,17 @@ void grab_swap_token(void)
/* We have the token. Let others know we still need it. */
if (has_swap_token(current->mm)) {
current->mm->recent_pagein = 1;
+ if (unlikely(!swap_token_default_timeout))
+ disable_swap_token();
return;
}
if (time_after(jiffies, swap_token_check)) {
- /* Can't get swapout protection if we exceed our RSS limit. */
- // if (current->mm->rss > current->mm->rlimit_rss)
- // return;
+ if (!swap_token_default_timeout) {
+ swap_token_check = jiffies + SWAP_TOKEN_CHECK_INTERVAL;
+ return;
+ }
/* ... or if we recently held the token. */
if (time_before(jiffies, current->mm->swap_token_time))
@@ -95,6 +98,7 @@ void __put_swap_token(struct mm_struct *mm)
{
spin_lock(&swap_token_lock);
if (likely(mm == swap_token_mm)) {
+ mm->swap_token_time = jiffies + SWAP_TOKEN_CHECK_INTERVAL;
swap_token_mm = &init_mm;
swap_token_check = jiffies;
}
diff --git a/mm/truncate.c b/mm/truncate.c
index 29c18f68dc3..9173ab50060 100644
--- a/mm/truncate.c
+++ b/mm/truncate.c
@@ -282,8 +282,8 @@ int invalidate_inode_pages2_range(struct address_space *mapping,
* Zap the rest of the file in one hit.
*/
unmap_mapping_range(mapping,
- page_index << PAGE_CACHE_SHIFT,
- (end - page_index + 1)
+ (loff_t)page_index<<PAGE_CACHE_SHIFT,
+ (loff_t)(end - page_index + 1)
<< PAGE_CACHE_SHIFT,
0);
did_range_unmap = 1;
@@ -292,7 +292,7 @@ int invalidate_inode_pages2_range(struct address_space *mapping,
* Just zap this page
*/
unmap_mapping_range(mapping,
- page_index << PAGE_CACHE_SHIFT,
+ (loff_t)page_index<<PAGE_CACHE_SHIFT,
PAGE_CACHE_SIZE, 0);
}
}
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 28130541270..b0cd81c32de 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -201,13 +201,25 @@ static int shrink_slab(unsigned long scanned, gfp_t gfp_mask,
list_for_each_entry(shrinker, &shrinker_list, list) {
unsigned long long delta;
unsigned long total_scan;
+ unsigned long max_pass = (*shrinker->shrinker)(0, gfp_mask);
delta = (4 * scanned) / shrinker->seeks;
- delta *= (*shrinker->shrinker)(0, gfp_mask);
+ delta *= max_pass;
do_div(delta, lru_pages + 1);
shrinker->nr += delta;
- if (shrinker->nr < 0)
- shrinker->nr = LONG_MAX; /* It wrapped! */
+ if (shrinker->nr < 0) {
+ printk(KERN_ERR "%s: nr=%ld\n",
+ __FUNCTION__, shrinker->nr);
+ shrinker->nr = max_pass;
+ }
+
+ /*
+ * Avoid risking looping forever due to too large nr value:
+ * never try to free more than twice the estimate number of
+ * freeable entries.
+ */
+ if (shrinker->nr > max_pass * 2)
+ shrinker->nr = max_pass * 2;
total_scan = shrinker->nr;
shrinker->nr = 0;
@@ -407,7 +419,7 @@ static int shrink_list(struct list_head *page_list, struct scan_control *sc)
if (PageWriteback(page))
goto keep_locked;
- referenced = page_referenced(page, 1, sc->priority <= 0);
+ referenced = page_referenced(page, 1);
/* In active use or really unfreeable? Activate it. */
if (referenced && page_mapping_inuse(page))
goto activate_locked;
@@ -756,7 +768,7 @@ refill_inactive_zone(struct zone *zone, struct scan_control *sc)
if (page_mapped(page)) {
if (!reclaim_mapped ||
(total_swap_pages == 0 && PageAnon(page)) ||
- page_referenced(page, 0, sc->priority <= 0)) {
+ page_referenced(page, 0)) {
list_add(&page->lru, &l_active);
continue;
}
@@ -960,6 +972,8 @@ int try_to_free_pages(struct zone **zones, gfp_t gfp_mask)
sc.nr_reclaimed = 0;
sc.priority = priority;
sc.swap_cluster_max = SWAP_CLUSTER_MAX;
+ if (!priority)
+ disable_swap_token();
shrink_caches(zones, &sc);
shrink_slab(sc.nr_scanned, gfp_mask, lru_pages);
if (reclaim_state) {
@@ -1056,6 +1070,10 @@ loop_again:
int end_zone = 0; /* Inclusive. 0 = ZONE_DMA */
unsigned long lru_pages = 0;
+ /* The swap token gets in the way of swapout... */
+ if (!priority)
+ disable_swap_token();
+
all_zones_ok = 1;
if (nr_pages == 0) {
@@ -1360,6 +1378,7 @@ int zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order)
sc.nr_reclaimed = 0;
/* scan at the highest priority */
sc.priority = 0;
+ disable_swap_token();
if (nr_pages > SWAP_CLUSTER_MAX)
sc.swap_cluster_max = nr_pages;