#include <linux/module.h>
#include <linux/rmap.h>
#include <linux/security.h>
+#include <linux/acct.h>
#include <linux/backing-dev.h>
+#include <linux/syscalls.h>
#include <asm/pgtable.h>
#include <asm/tlbflush.h>
#include <linux/swapops.h>
-#include <linux/vs_base.h>
#include <linux/vs_memory.h>
-spinlock_t swaplock = SPIN_LOCK_UNLOCKED;
+DEFINE_SPINLOCK(swaplock);
unsigned int nr_swapfiles;
long total_swap_pages;
static int swap_overflow;
set_pte(dir, pte_mkold(mk_pte(page, vma->vm_page_prot)));
page_add_anon_rmap(page, vma, address);
swap_free(entry);
+ acct_update_integrals();
+ update_mem_hiwater();
}
/* vma->vm_mm->page_table_lock is held */
-static unsigned long unuse_pmd(struct vm_area_struct * vma, pmd_t *dir,
- unsigned long address, unsigned long size, unsigned long offset,
+static unsigned long unuse_pmd(struct vm_area_struct *vma, pmd_t *dir,
+ unsigned long address, unsigned long end,
swp_entry_t entry, struct page *page)
{
- pte_t * pte;
- unsigned long end;
+ pte_t *pte;
pte_t swp_pte = swp_entry_to_pte(entry);
if (pmd_none(*dir))
return 0;
}
pte = pte_offset_map(dir, address);
- offset += address & PMD_MASK;
- address &= ~PMD_MASK;
- end = address + size;
- if (end > PMD_SIZE)
- end = PMD_SIZE;
do {
/*
* swapoff spends a _lot_ of time in this loop!
* Test inline before going to call unuse_pte.
*/
if (unlikely(pte_same(*pte, swp_pte))) {
- unuse_pte(vma, offset + address, pte, entry, page);
+ unuse_pte(vma, address, pte, entry, page);
pte_unmap(pte);
/*
activate_page(page);
/* add 1 since address may be 0 */
- return 1 + offset + address;
+ return 1 + address;
}
address += PAGE_SIZE;
pte++;
- } while (address && (address < end));
+ } while (address < end);
pte_unmap(pte - 1);
return 0;
}
/* vma->vm_mm->page_table_lock is held */
-static unsigned long unuse_pgd(struct vm_area_struct * vma, pgd_t *dir,
- unsigned long address, unsigned long size,
+static unsigned long unuse_pud(struct vm_area_struct *vma, pud_t *pud,
+ unsigned long address, unsigned long end,
swp_entry_t entry, struct page *page)
{
- pmd_t * pmd;
- unsigned long offset, end;
+ pmd_t *pmd;
+ unsigned long next;
unsigned long foundaddr;
- if (pgd_none(*dir))
+ if (pud_none(*pud))
return 0;
- if (pgd_bad(*dir)) {
- pgd_ERROR(*dir);
- pgd_clear(dir);
+ if (pud_bad(*pud)) {
+ pud_ERROR(*pud);
+ pud_clear(pud);
return 0;
}
- pmd = pmd_offset(dir, address);
- offset = address & PGDIR_MASK;
- address &= ~PGDIR_MASK;
- end = address + size;
- if (end > PGDIR_SIZE)
- end = PGDIR_SIZE;
- if (address >= end)
- BUG();
+ pmd = pmd_offset(pud, address);
do {
- foundaddr = unuse_pmd(vma, pmd, address, end - address,
- offset, entry, page);
+ next = (address + PMD_SIZE) & PMD_MASK;
+ if (next > end || !next)
+ next = end;
+ foundaddr = unuse_pmd(vma, pmd, address, next, entry, page);
if (foundaddr)
return foundaddr;
- address = (address + PMD_SIZE) & PMD_MASK;
+ address = next;
pmd++;
- } while (address && (address < end));
+ } while (address < end);
+ return 0;
+}
+
+/* vma->vm_mm->page_table_lock is held */
+static unsigned long unuse_pgd(struct vm_area_struct *vma, pgd_t *pgd,
+ unsigned long address, unsigned long end,
+ swp_entry_t entry, struct page *page)
+{
+ pud_t *pud;
+ unsigned long next;
+ unsigned long foundaddr;
+
+ if (pgd_none(*pgd))
+ return 0;
+ if (pgd_bad(*pgd)) {
+ pgd_ERROR(*pgd);
+ pgd_clear(pgd);
+ return 0;
+ }
+ pud = pud_offset(pgd, address);
+ do {
+ next = (address + PUD_SIZE) & PUD_MASK;
+ if (next > end || !next)
+ next = end;
+ foundaddr = unuse_pud(vma, pud, address, next, entry, page);
+ if (foundaddr)
+ return foundaddr;
+ address = next;
+ pud++;
+ } while (address < end);
return 0;
}
/* vma->vm_mm->page_table_lock is held */
-static unsigned long unuse_vma(struct vm_area_struct * vma,
+static unsigned long unuse_vma(struct vm_area_struct *vma,
swp_entry_t entry, struct page *page)
{
- pgd_t *pgdir;
- unsigned long start, end;
+ pgd_t *pgd;
+ unsigned long address, next, end;
unsigned long foundaddr;
if (page->mapping) {
- start = page_address_in_vma(page, vma);
- if (start == -EFAULT)
+ address = page_address_in_vma(page, vma);
+ if (address == -EFAULT)
return 0;
else
- end = start + PAGE_SIZE;
+ end = address + PAGE_SIZE;
} else {
- start = vma->vm_start;
+ address = vma->vm_start;
end = vma->vm_end;
}
- pgdir = pgd_offset(vma->vm_mm, start);
+ pgd = pgd_offset(vma->vm_mm, address);
do {
- foundaddr = unuse_pgd(vma, pgdir, start, end - start,
- entry, page);
+ next = (address + PGDIR_SIZE) & PGDIR_MASK;
+ if (next > end || !next)
+ next = end;
+ foundaddr = unuse_pgd(vma, pgd, address, next, entry, page);
if (foundaddr)
return foundaddr;
- start = (start + PGDIR_SIZE) & PGDIR_MASK;
- pgdir++;
- } while (start && (start < end));
+ address = next;
+ pgd++;
+ } while (address < end);
return 0;
}
*
* A simpler strategy would be to start at the last mm we
* freed the previous entry from; but that would take less
- * advantage of mmlist ordering (now preserved by swap_out()),
- * which clusters forked address spaces together, most recent
- * child immediately after parent. If we race with dup_mmap(),
- * we very much want to resolve parent before child, otherwise
- * we may miss some entries: using last mm would invert that.
+ * advantage of mmlist ordering, which clusters forked mms
+ * together, child after parent. If we race with dup_mmap(), we
+ * prefer to resolve parent before child, lest we miss entries
+ * duplicated after we scanned child: using last mm would invert
+ * that. Though it's only a serious concern when an overflowed
+ * swap count is reset from SWAP_MAP_MAX, preventing a rescan.
*/
start_mm = &init_mm;
atomic_inc(&init_mm.mm_users);
/*
* Keep on scanning until all entries have gone. Usually,
* one pass through swap_map is enough, but not necessarily:
- * mmput() removes mm from mmlist before exit_mmap() and its
- * zap_page_range(). That's not too bad, those entries are
- * on their way out, and handled faster there than here.
- * do_munmap() behaves similarly, taking the range out of mm's
- * vma list before zap_page_range(). But unfortunately, when
- * unmapping a part of a vma, it takes the whole out first,
- * then reinserts what's left after (might even reschedule if
- * open() method called) - so swap entries may be invisible
- * to swapoff for a while, then reappear - but that is rare.
+ * there are races when an instance of an entry might be missed.
*/
while ((i = find_next_to_unuse(si, i)) != 0) {
if (signal_pending(current)) {
wait_on_page_writeback(page);
/*
- * Remove all references to entry, without blocking.
+ * Remove all references to entry.
* Whenever we reach init_mm, there's no address space
* to search, but use it as a reminder to search shmem.
*/
while (*swap_map > 1 && !retval &&
(p = p->next) != &start_mm->mmlist) {
mm = list_entry(p, struct mm_struct, mmlist);
- atomic_inc(&mm->mm_users);
+ if (atomic_inc_return(&mm->mm_users) == 1) {
+ atomic_dec(&mm->mm_users);
+ continue;
+ }
spin_unlock(&mmlist_lock);
mmput(prev_mm);
prev_mm = mm;
return retval;
}
+/*
+ * After a successful try_to_unuse, if no swap is now in use, we know we
+ * can empty the mmlist. swap_list_lock must be held on entry and exit.
+ * Note that mmlist_lock nests inside swap_list_lock, and an mm must be
+ * added to the mmlist just after page_duplicate - before would be racy.
+ */
+static void drain_mmlist(void)
+{
+ struct list_head *p, *next;
+ unsigned int i;
+
+ for (i = 0; i < nr_swapfiles; i++)
+ if (swap_info[i].inuse_pages)
+ return;
+ spin_lock(&mmlist_lock);
+ list_for_each_safe(p, next, &init_mm.mmlist)
+ list_del_init(p);
+ spin_unlock(&mmlist_lock);
+}
+
/*
* Use this swapdev's extent info to locate the (PAGE_SIZE) block which
* corresponds to page offset `offset'.
}
down(&swapon_sem);
swap_list_lock();
+ drain_mmlist();
swap_device_lock(p);
swap_file = p->swap_file;
p->swap_file = NULL;
p->highest_bit = 0;
p->cluster_nr = 0;
p->inuse_pages = 0;
- p->sdev_lock = SPIN_LOCK_UNLOCKED;
+ spin_lock_init(&p->sdev_lock);
p->next = -1;
if (swap_flags & SWAP_FLAG_PREFER) {
p->prio =
++least_priority;
swap_list_unlock();
destroy_swap_extents(p);
- if (swap_map)
- vfree(swap_map);
+ vfree(swap_map);
if (swap_file)
filp_close(swap_file, NULL);
out:
git://git.onelab.eu / linux-2.6.git / blobdiff