#include <linux/gfp.h>
#include <linux/migrate.h>
#include <linux/string.h>
-#include <linux/dma-debug.h>
#include <linux/debugfs.h>
#include <linux/userfaultfd_k.h>
#include <linux/dax.h>
#include <linux/numa.h>
#include <linux/perf_event.h>
#include <linux/ptrace.h>
+#include <linux/vmalloc.h>
#include <trace/events/kmem.h>
#include <asm/tlb.h>
#include <asm/tlbflush.h>
+#include "pgalloc-track.h"
#include "internal.h"
#if defined(LAST_CPUPID_NOT_IN_PAGE_FLAGS) && !defined(CONFIG_COMPILE_TEST)
* covered by this vma.
*/
-static inline unsigned long
-copy_one_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm,
+static unsigned long
+copy_nonpresent_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm,
pte_t *dst_pte, pte_t *src_pte, struct vm_area_struct *vma,
unsigned long addr, int *rss)
{
unsigned long vm_flags = vma->vm_flags;
pte_t pte = *src_pte;
struct page *page;
+ swp_entry_t entry = pte_to_swp_entry(pte);
+
+ if (likely(!non_swap_entry(entry))) {
+ if (swap_duplicate(entry) < 0)
+ return entry.val;
+
+ /* make sure dst_mm is on swapoff's mmlist. */
+ if (unlikely(list_empty(&dst_mm->mmlist))) {
+ spin_lock(&mmlist_lock);
+ if (list_empty(&dst_mm->mmlist))
+ list_add(&dst_mm->mmlist,
+ &src_mm->mmlist);
+ spin_unlock(&mmlist_lock);
+ }
+ rss[MM_SWAPENTS]++;
+ } else if (is_migration_entry(entry)) {
+ page = migration_entry_to_page(entry);
- /* pte contains position in swap or file, so copy. */
- if (unlikely(!pte_present(pte))) {
- swp_entry_t entry = pte_to_swp_entry(pte);
-
- if (likely(!non_swap_entry(entry))) {
- if (swap_duplicate(entry) < 0)
- return entry.val;
-
- /* make sure dst_mm is on swapoff's mmlist. */
- if (unlikely(list_empty(&dst_mm->mmlist))) {
- spin_lock(&mmlist_lock);
- if (list_empty(&dst_mm->mmlist))
- list_add(&dst_mm->mmlist,
- &src_mm->mmlist);
- spin_unlock(&mmlist_lock);
- }
- rss[MM_SWAPENTS]++;
- } else if (is_migration_entry(entry)) {
- page = migration_entry_to_page(entry);
-
- rss[mm_counter(page)]++;
-
- if (is_write_migration_entry(entry) &&
- is_cow_mapping(vm_flags)) {
- /*
- * COW mappings require pages in both
- * parent and child to be set to read.
- */
- make_migration_entry_read(&entry);
- pte = swp_entry_to_pte(entry);
- if (pte_swp_soft_dirty(*src_pte))
- pte = pte_swp_mksoft_dirty(pte);
- if (pte_swp_uffd_wp(*src_pte))
- pte = pte_swp_mkuffd_wp(pte);
- set_pte_at(src_mm, addr, src_pte, pte);
- }
- } else if (is_device_private_entry(entry)) {
- page = device_private_entry_to_page(entry);
+ rss[mm_counter(page)]++;
+ if (is_write_migration_entry(entry) &&
+ is_cow_mapping(vm_flags)) {
/*
- * Update rss count even for unaddressable pages, as
- * they should treated just like normal pages in this
- * respect.
- *
- * We will likely want to have some new rss counters
- * for unaddressable pages, at some point. But for now
- * keep things as they are.
+ * COW mappings require pages in both
+ * parent and child to be set to read.
*/
- get_page(page);
- rss[mm_counter(page)]++;
- page_dup_rmap(page, false);
+ make_migration_entry_read(&entry);
+ pte = swp_entry_to_pte(entry);
+ if (pte_swp_soft_dirty(*src_pte))
+ pte = pte_swp_mksoft_dirty(pte);
+ if (pte_swp_uffd_wp(*src_pte))
+ pte = pte_swp_mkuffd_wp(pte);
+ set_pte_at(src_mm, addr, src_pte, pte);
+ }
+ } else if (is_device_private_entry(entry)) {
+ page = device_private_entry_to_page(entry);
- /*
- * We do not preserve soft-dirty information, because so
- * far, checkpoint/restore is the only feature that
- * requires that. And checkpoint/restore does not work
- * when a device driver is involved (you cannot easily
- * save and restore device driver state).
- */
- if (is_write_device_private_entry(entry) &&
- is_cow_mapping(vm_flags)) {
- make_device_private_entry_read(&entry);
- pte = swp_entry_to_pte(entry);
- if (pte_swp_uffd_wp(*src_pte))
- pte = pte_swp_mkuffd_wp(pte);
- set_pte_at(src_mm, addr, src_pte, pte);
- }
+ /*
+ * Update rss count even for unaddressable pages, as
+ * they should treated just like normal pages in this
+ * respect.
+ *
+ * We will likely want to have some new rss counters
+ * for unaddressable pages, at some point. But for now
+ * keep things as they are.
+ */
+ get_page(page);
+ rss[mm_counter(page)]++;
+ page_dup_rmap(page, false);
+
+ /*
+ * We do not preserve soft-dirty information, because so
+ * far, checkpoint/restore is the only feature that
+ * requires that. And checkpoint/restore does not work
+ * when a device driver is involved (you cannot easily
+ * save and restore device driver state).
+ */
+ if (is_write_device_private_entry(entry) &&
+ is_cow_mapping(vm_flags)) {
+ make_device_private_entry_read(&entry);
+ pte = swp_entry_to_pte(entry);
+ if (pte_swp_uffd_wp(*src_pte))
+ pte = pte_swp_mkuffd_wp(pte);
+ set_pte_at(src_mm, addr, src_pte, pte);
}
- goto out_set_pte;
+ }
+ set_pte_at(dst_mm, addr, dst_pte, pte);
+ return 0;
+}
+
+/*
+ * Copy a present and normal page if necessary.
+ *
+ * NOTE! The usual case is that this doesn't need to do
+ * anything, and can just return a positive value. That
+ * will let the caller know that it can just increase
+ * the page refcount and re-use the pte the traditional
+ * way.
+ *
+ * But _if_ we need to copy it because it needs to be
+ * pinned in the parent (and the child should get its own
+ * copy rather than just a reference to the same page),
+ * we'll do that here and return zero to let the caller
+ * know we're done.
+ *
+ * And if we need a pre-allocated page but don't yet have
+ * one, return a negative error to let the preallocation
+ * code know so that it can do so outside the page table
+ * lock.
+ */
+static inline int
+copy_present_page(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma,
+ pte_t *dst_pte, pte_t *src_pte, unsigned long addr, int *rss,
+ struct page **prealloc, pte_t pte, struct page *page)
+{
+ struct mm_struct *src_mm = src_vma->vm_mm;
+ struct page *new_page;
+
+ if (!is_cow_mapping(src_vma->vm_flags))
+ return 1;
+
+ /*
+ * What we want to do is to check whether this page may
+ * have been pinned by the parent process. If so,
+ * instead of wrprotect the pte on both sides, we copy
+ * the page immediately so that we'll always guarantee
+ * the pinned page won't be randomly replaced in the
+ * future.
+ *
+ * The page pinning checks are just "has this mm ever
+ * seen pinning", along with the (inexact) check of
+ * the page count. That might give false positives for
+ * for pinning, but it will work correctly.
+ */
+ if (likely(!atomic_read(&src_mm->has_pinned)))
+ return 1;
+ if (likely(!page_maybe_dma_pinned(page)))
+ return 1;
+
+ new_page = *prealloc;
+ if (!new_page)
+ return -EAGAIN;
+
+ /*
+ * We have a prealloc page, all good! Take it
+ * over and copy the page & arm it.
+ */
+ *prealloc = NULL;
+ copy_user_highpage(new_page, page, addr, src_vma);
+ __SetPageUptodate(new_page);
+ page_add_new_anon_rmap(new_page, dst_vma, addr, false);
+ lru_cache_add_inactive_or_unevictable(new_page, dst_vma);
+ rss[mm_counter(new_page)]++;
+
+ /* All done, just insert the new page copy in the child */
+ pte = mk_pte(new_page, dst_vma->vm_page_prot);
+ pte = maybe_mkwrite(pte_mkdirty(pte), dst_vma);
+ set_pte_at(dst_vma->vm_mm, addr, dst_pte, pte);
+ return 0;
+}
+
+/*
+ * Copy one pte. Returns 0 if succeeded, or -EAGAIN if one preallocated page
+ * is required to copy this pte.
+ */
+static inline int
+copy_present_pte(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma,
+ pte_t *dst_pte, pte_t *src_pte, unsigned long addr, int *rss,
+ struct page **prealloc)
+{
+ struct mm_struct *src_mm = src_vma->vm_mm;
+ unsigned long vm_flags = src_vma->vm_flags;
+ pte_t pte = *src_pte;
+ struct page *page;
+
+ page = vm_normal_page(src_vma, addr, pte);
+ if (page) {
+ int retval;
+
+ retval = copy_present_page(dst_vma, src_vma, dst_pte, src_pte,
+ addr, rss, prealloc, pte, page);
+ if (retval <= 0)
+ return retval;
+
+ get_page(page);
+ page_dup_rmap(page, false);
+ rss[mm_counter(page)]++;
}
/*
if (!(vm_flags & VM_UFFD_WP))
pte = pte_clear_uffd_wp(pte);
- page = vm_normal_page(vma, addr, pte);
- if (page) {
- get_page(page);
- page_dup_rmap(page, false);
- rss[mm_counter(page)]++;
+ set_pte_at(dst_vma->vm_mm, addr, dst_pte, pte);
+ return 0;
+}
+
+static inline struct page *
+page_copy_prealloc(struct mm_struct *src_mm, struct vm_area_struct *vma,
+ unsigned long addr)
+{
+ struct page *new_page;
+
+ new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, addr);
+ if (!new_page)
+ return NULL;
+
+ if (mem_cgroup_charge(new_page, src_mm, GFP_KERNEL)) {
+ put_page(new_page);
+ return NULL;
}
+ cgroup_throttle_swaprate(new_page, GFP_KERNEL);
-out_set_pte:
- set_pte_at(dst_mm, addr, dst_pte, pte);
- return 0;
+ return new_page;
}
-static int copy_pte_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
- pmd_t *dst_pmd, pmd_t *src_pmd, struct vm_area_struct *vma,
- unsigned long addr, unsigned long end)
+static int
+copy_pte_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma,
+ pmd_t *dst_pmd, pmd_t *src_pmd, unsigned long addr,
+ unsigned long end)
{
+ struct mm_struct *dst_mm = dst_vma->vm_mm;
+ struct mm_struct *src_mm = src_vma->vm_mm;
pte_t *orig_src_pte, *orig_dst_pte;
pte_t *src_pte, *dst_pte;
spinlock_t *src_ptl, *dst_ptl;
- int progress = 0;
+ int progress, ret = 0;
int rss[NR_MM_COUNTERS];
swp_entry_t entry = (swp_entry_t){0};
+ struct page *prealloc = NULL;
again:
+ progress = 0;
init_rss_vec(rss);
dst_pte = pte_alloc_map_lock(dst_mm, dst_pmd, addr, &dst_ptl);
- if (!dst_pte)
- return -ENOMEM;
+ if (!dst_pte) {
+ ret = -ENOMEM;
+ goto out;
+ }
src_pte = pte_offset_map(src_pmd, addr);
src_ptl = pte_lockptr(src_mm, src_pmd);
spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING);
progress++;
continue;
}
- entry.val = copy_one_pte(dst_mm, src_mm, dst_pte, src_pte,
- vma, addr, rss);
- if (entry.val)
+ if (unlikely(!pte_present(*src_pte))) {
+ entry.val = copy_nonpresent_pte(dst_mm, src_mm,
+ dst_pte, src_pte,
+ src_vma, addr, rss);
+ if (entry.val)
+ break;
+ progress += 8;
+ continue;
+ }
+ /* copy_present_pte() will clear `*prealloc' if consumed */
+ ret = copy_present_pte(dst_vma, src_vma, dst_pte, src_pte,
+ addr, rss, &prealloc);
+ /*
+ * If we need a pre-allocated page for this pte, drop the
+ * locks, allocate, and try again.
+ */
+ if (unlikely(ret == -EAGAIN))
break;
+ if (unlikely(prealloc)) {
+ /*
+ * pre-alloc page cannot be reused by next time so as
+ * to strictly follow mempolicy (e.g., alloc_page_vma()
+ * will allocate page according to address). This
+ * could only happen if one pinned pte changed.
+ */
+ put_page(prealloc);
+ prealloc = NULL;
+ }
progress += 8;
} while (dst_pte++, src_pte++, addr += PAGE_SIZE, addr != end);
cond_resched();
if (entry.val) {
- if (add_swap_count_continuation(entry, GFP_KERNEL) < 0)
+ if (add_swap_count_continuation(entry, GFP_KERNEL) < 0) {
+ ret = -ENOMEM;
+ goto out;
+ }
+ entry.val = 0;
+ } else if (ret) {
+ WARN_ON_ONCE(ret != -EAGAIN);
+ prealloc = page_copy_prealloc(src_mm, src_vma, addr);
+ if (!prealloc)
return -ENOMEM;
- progress = 0;
+ /* We've captured and resolved the error. Reset, try again. */
+ ret = 0;
}
if (addr != end)
goto again;
- return 0;
+out:
+ if (unlikely(prealloc))
+ put_page(prealloc);
+ return ret;
}
-static inline int copy_pmd_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
- pud_t *dst_pud, pud_t *src_pud, struct vm_area_struct *vma,
- unsigned long addr, unsigned long end)
+static inline int
+copy_pmd_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma,
+ pud_t *dst_pud, pud_t *src_pud, unsigned long addr,
+ unsigned long end)
{
+ struct mm_struct *dst_mm = dst_vma->vm_mm;
+ struct mm_struct *src_mm = src_vma->vm_mm;
pmd_t *src_pmd, *dst_pmd;
unsigned long next;
if (is_swap_pmd(*src_pmd) || pmd_trans_huge(*src_pmd)
|| pmd_devmap(*src_pmd)) {
int err;
- VM_BUG_ON_VMA(next-addr != HPAGE_PMD_SIZE, vma);
+ VM_BUG_ON_VMA(next-addr != HPAGE_PMD_SIZE, src_vma);
err = copy_huge_pmd(dst_mm, src_mm,
- dst_pmd, src_pmd, addr, vma);
+ dst_pmd, src_pmd, addr, src_vma);
if (err == -ENOMEM)
return -ENOMEM;
if (!err)
}
if (pmd_none_or_clear_bad(src_pmd))
continue;
- if (copy_pte_range(dst_mm, src_mm, dst_pmd, src_pmd,
- vma, addr, next))
+ if (copy_pte_range(dst_vma, src_vma, dst_pmd, src_pmd,
+ addr, next))
return -ENOMEM;
} while (dst_pmd++, src_pmd++, addr = next, addr != end);
return 0;
}
-static inline int copy_pud_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
- p4d_t *dst_p4d, p4d_t *src_p4d, struct vm_area_struct *vma,
- unsigned long addr, unsigned long end)
+static inline int
+copy_pud_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma,
+ p4d_t *dst_p4d, p4d_t *src_p4d, unsigned long addr,
+ unsigned long end)
{
+ struct mm_struct *dst_mm = dst_vma->vm_mm;
+ struct mm_struct *src_mm = src_vma->vm_mm;
pud_t *src_pud, *dst_pud;
unsigned long next;
if (pud_trans_huge(*src_pud) || pud_devmap(*src_pud)) {
int err;
- VM_BUG_ON_VMA(next-addr != HPAGE_PUD_SIZE, vma);
+ VM_BUG_ON_VMA(next-addr != HPAGE_PUD_SIZE, src_vma);
err = copy_huge_pud(dst_mm, src_mm,
- dst_pud, src_pud, addr, vma);
+ dst_pud, src_pud, addr, src_vma);
if (err == -ENOMEM)
return -ENOMEM;
if (!err)
}
if (pud_none_or_clear_bad(src_pud))
continue;
- if (copy_pmd_range(dst_mm, src_mm, dst_pud, src_pud,
- vma, addr, next))
+ if (copy_pmd_range(dst_vma, src_vma, dst_pud, src_pud,
+ addr, next))
return -ENOMEM;
} while (dst_pud++, src_pud++, addr = next, addr != end);
return 0;
}
-static inline int copy_p4d_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
- pgd_t *dst_pgd, pgd_t *src_pgd, struct vm_area_struct *vma,
- unsigned long addr, unsigned long end)
+static inline int
+copy_p4d_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma,
+ pgd_t *dst_pgd, pgd_t *src_pgd, unsigned long addr,
+ unsigned long end)
{
+ struct mm_struct *dst_mm = dst_vma->vm_mm;
p4d_t *src_p4d, *dst_p4d;
unsigned long next;
next = p4d_addr_end(addr, end);
if (p4d_none_or_clear_bad(src_p4d))
continue;
- if (copy_pud_range(dst_mm, src_mm, dst_p4d, src_p4d,
- vma, addr, next))
+ if (copy_pud_range(dst_vma, src_vma, dst_p4d, src_p4d,
+ addr, next))
return -ENOMEM;
} while (dst_p4d++, src_p4d++, addr = next, addr != end);
return 0;
}
-int copy_page_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
- struct vm_area_struct *vma)
+int
+copy_page_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma)
{
pgd_t *src_pgd, *dst_pgd;
unsigned long next;
- unsigned long addr = vma->vm_start;
- unsigned long end = vma->vm_end;
+ unsigned long addr = src_vma->vm_start;
+ unsigned long end = src_vma->vm_end;
+ struct mm_struct *dst_mm = dst_vma->vm_mm;
+ struct mm_struct *src_mm = src_vma->vm_mm;
struct mmu_notifier_range range;
bool is_cow;
int ret;
* readonly mappings. The tradeoff is that copy_page_range is more
* efficient than faulting.
*/
- if (!(vma->vm_flags & (VM_HUGETLB | VM_PFNMAP | VM_MIXEDMAP)) &&
- !vma->anon_vma)
+ if (!(src_vma->vm_flags & (VM_HUGETLB | VM_PFNMAP | VM_MIXEDMAP)) &&
+ !src_vma->anon_vma)
return 0;
- if (is_vm_hugetlb_page(vma))
- return copy_hugetlb_page_range(dst_mm, src_mm, vma);
+ if (is_vm_hugetlb_page(src_vma))
+ return copy_hugetlb_page_range(dst_mm, src_mm, src_vma);
- if (unlikely(vma->vm_flags & VM_PFNMAP)) {
+ if (unlikely(src_vma->vm_flags & VM_PFNMAP)) {
/*
* We do not free on error cases below as remove_vma
* gets called on error from higher level routine
*/
- ret = track_pfn_copy(vma);
+ ret = track_pfn_copy(src_vma);
if (ret)
return ret;
}
* parent mm. And a permission downgrade will only happen if
* is_cow_mapping() returns true.
*/
- is_cow = is_cow_mapping(vma->vm_flags);
+ is_cow = is_cow_mapping(src_vma->vm_flags);
if (is_cow) {
mmu_notifier_range_init(&range, MMU_NOTIFY_PROTECTION_PAGE,
- 0, vma, src_mm, addr, end);
+ 0, src_vma, src_mm, addr, end);
mmu_notifier_invalidate_range_start(&range);
}
next = pgd_addr_end(addr, end);
if (pgd_none_or_clear_bad(src_pgd))
continue;
- if (unlikely(copy_p4d_range(dst_mm, src_mm, dst_pgd, src_pgd,
- vma, addr, next))) {
+ if (unlikely(copy_p4d_range(dst_vma, src_vma, dst_pgd, src_pgd,
+ addr, next))) {
ret = -ENOMEM;
break;
}
static int apply_to_pte_range(struct mm_struct *mm, pmd_t *pmd,
unsigned long addr, unsigned long end,
- pte_fn_t fn, void *data, bool create)
+ pte_fn_t fn, void *data, bool create,
+ pgtbl_mod_mask *mask)
{
pte_t *pte;
int err = 0;
if (create) {
pte = (mm == &init_mm) ?
- pte_alloc_kernel(pmd, addr) :
+ pte_alloc_kernel_track(pmd, addr, mask) :
pte_alloc_map_lock(mm, pmd, addr, &ptl);
if (!pte)
return -ENOMEM;
break;
}
} while (addr += PAGE_SIZE, addr != end);
+ *mask |= PGTBL_PTE_MODIFIED;
arch_leave_lazy_mmu_mode();
static int apply_to_pmd_range(struct mm_struct *mm, pud_t *pud,
unsigned long addr, unsigned long end,
- pte_fn_t fn, void *data, bool create)
+ pte_fn_t fn, void *data, bool create,
+ pgtbl_mod_mask *mask)
{
pmd_t *pmd;
unsigned long next;
BUG_ON(pud_huge(*pud));
if (create) {
- pmd = pmd_alloc(mm, pud, addr);
+ pmd = pmd_alloc_track(mm, pud, addr, mask);
if (!pmd)
return -ENOMEM;
} else {
next = pmd_addr_end(addr, end);
if (create || !pmd_none_or_clear_bad(pmd)) {
err = apply_to_pte_range(mm, pmd, addr, next, fn, data,
- create);
+ create, mask);
if (err)
break;
}
static int apply_to_pud_range(struct mm_struct *mm, p4d_t *p4d,
unsigned long addr, unsigned long end,
- pte_fn_t fn, void *data, bool create)
+ pte_fn_t fn, void *data, bool create,
+ pgtbl_mod_mask *mask)
{
pud_t *pud;
unsigned long next;
int err = 0;
if (create) {
- pud = pud_alloc(mm, p4d, addr);
+ pud = pud_alloc_track(mm, p4d, addr, mask);
if (!pud)
return -ENOMEM;
} else {
next = pud_addr_end(addr, end);
if (create || !pud_none_or_clear_bad(pud)) {
err = apply_to_pmd_range(mm, pud, addr, next, fn, data,
- create);
+ create, mask);
if (err)
break;
}
static int apply_to_p4d_range(struct mm_struct *mm, pgd_t *pgd,
unsigned long addr, unsigned long end,
- pte_fn_t fn, void *data, bool create)
+ pte_fn_t fn, void *data, bool create,
+ pgtbl_mod_mask *mask)
{
p4d_t *p4d;
unsigned long next;
int err = 0;
if (create) {
- p4d = p4d_alloc(mm, pgd, addr);
+ p4d = p4d_alloc_track(mm, pgd, addr, mask);
if (!p4d)
return -ENOMEM;
} else {
next = p4d_addr_end(addr, end);
if (create || !p4d_none_or_clear_bad(p4d)) {
err = apply_to_pud_range(mm, p4d, addr, next, fn, data,
- create);
+ create, mask);
if (err)
break;
}
void *data, bool create)
{
pgd_t *pgd;
- unsigned long next;
+ unsigned long start = addr, next;
unsigned long end = addr + size;
+ pgtbl_mod_mask mask = 0;
int err = 0;
if (WARN_ON(addr >= end))
next = pgd_addr_end(addr, end);
if (!create && pgd_none_or_clear_bad(pgd))
continue;
- err = apply_to_p4d_range(mm, pgd, addr, next, fn, data, create);
+ err = apply_to_p4d_range(mm, pgd, addr, next, fn, data, create, &mask);
if (err)
break;
} while (pgd++, addr = next, addr != end);
+ if (mask & ARCH_PAGE_TABLE_SYNC_MASK)
+ arch_sync_kernel_mappings(start, start + size);
+
return err;
}
if (ptep_set_access_flags(vma, vmf->address, vmf->pte, entry, 1))
update_mmu_cache(vma, vmf->address, vmf->pte);
pte_unmap_unlock(vmf->pte, vmf->ptl);
+ count_vm_event(PGREUSE);
}
/*
* not dirty accountable.
*/
if (PageAnon(vmf->page)) {
- int total_map_swapcount;
- if (PageKsm(vmf->page) && (PageSwapCache(vmf->page) ||
- page_count(vmf->page) != 1))
+ struct page *page = vmf->page;
+
+ /* PageKsm() doesn't necessarily raise the page refcount */
+ if (PageKsm(page) || page_count(page) != 1)
+ goto copy;
+ if (!trylock_page(page))
+ goto copy;
+ if (PageKsm(page) || page_mapcount(page) != 1 || page_count(page) != 1) {
+ unlock_page(page);
goto copy;
- if (!trylock_page(vmf->page)) {
- get_page(vmf->page);
- pte_unmap_unlock(vmf->pte, vmf->ptl);
- lock_page(vmf->page);
- vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd,
- vmf->address, &vmf->ptl);
- if (!pte_same(*vmf->pte, vmf->orig_pte)) {
- update_mmu_tlb(vma, vmf->address, vmf->pte);
- unlock_page(vmf->page);
- pte_unmap_unlock(vmf->pte, vmf->ptl);
- put_page(vmf->page);
- return 0;
- }
- put_page(vmf->page);
- }
- if (PageKsm(vmf->page)) {
- bool reused = reuse_ksm_page(vmf->page, vmf->vma,
- vmf->address);
- unlock_page(vmf->page);
- if (!reused)
- goto copy;
- wp_page_reuse(vmf);
- return VM_FAULT_WRITE;
- }
- if (reuse_swap_page(vmf->page, &total_map_swapcount)) {
- if (total_map_swapcount == 1) {
- /*
- * The page is all ours. Move it to
- * our anon_vma so the rmap code will
- * not search our parent or siblings.
- * Protected against the rmap code by
- * the page lock.
- */
- page_move_anon_rmap(vmf->page, vma);
- }
- unlock_page(vmf->page);
- wp_page_reuse(vmf);
- return VM_FAULT_WRITE;
}
- unlock_page(vmf->page);
+ /*
+ * Ok, we've got the only map reference, and the only
+ * page count reference, and the page is locked,
+ * it's dark out, and we're wearing sunglasses. Hit it.
+ */
+ unlock_page(page);
+ wp_page_reuse(vmf);
+ return VM_FAULT_WRITE;
} else if (unlikely((vma->vm_flags & (VM_WRITE|VM_SHARED)) ==
(VM_WRITE|VM_SHARED))) {
return wp_page_shared(vmf);
* unlock_page(A)
* lock_page(B)
* lock_page(B)
- * pte_alloc_pne
+ * pte_alloc_one
* shrink_page_list
* wait_on_page_writeback(A)
* SetPageWriteback(B)
* # flush A, B to clear the writeback
*/
if (pmd_none(*vmf->pmd) && !vmf->prealloc_pte) {
- vmf->prealloc_pte = pte_alloc_one(vmf->vma->vm_mm);
+ vmf->prealloc_pte = pte_alloc_one(vma->vm_mm);
if (!vmf->prealloc_pte)
return VM_FAULT_OOM;
smp_wmb(); /* See comment in __pte_alloc() */
unsigned long haddr = vmf->address & HPAGE_PMD_MASK;
pmd_t entry;
int i;
- vm_fault_t ret;
+ vm_fault_t ret = VM_FAULT_FALLBACK;
if (!transhuge_vma_suitable(vma, haddr))
- return VM_FAULT_FALLBACK;
+ return ret;
- ret = VM_FAULT_FALLBACK;
page = compound_head(page);
+ if (compound_order(page) != HPAGE_PMD_ORDER)
+ return ret;
/*
* Archs like ppc64 need additonal space to store information
/**
* alloc_set_pte - setup new PTE entry for given page and add reverse page
- * mapping. If needed, the fucntion allocates page table or use pre-allocated.
+ * mapping. If needed, the function allocates page table or use pre-allocated.
*
* @vmf: fault environment
* @page: page to map
projects / linux-2.6-microblaze.git / blobdiff