On Tue, 18 Apr 2006, KAMEZAWA Hiroyuki wrote:
> Then,
>
> if (is_migration_entry(entry)) {
> change_to_read_migration_entry(entry);
> copy_entry(entry);
> }
>
> is sane.
Hmmm... Looks like I need to do the patch. Is the following okay? This
will also only work on cow mappings.
Read/Write migration entries: Implement correct behavior in copy_one_pte
Migration entries with write permission must become SWP_MIGRATION_READ
entries if a COW mapping is processed. The migration entries from which
the copy is being made must also become SWP_MIGRATION_READ. This mimicks
the copying of pte for an anonymous page.
Signed-off-by: KAMEZAWA Hiroyuki <[email protected]>
Signed-off-by: Christoph Lameter <[email protected]>
Index: linux-2.6.17-rc1-mm2/mm/memory.c
===================================================================
--- linux-2.6.17-rc1-mm2.orig/mm/memory.c 2006-04-17 16:23:50.000000000 -0700
+++ linux-2.6.17-rc1-mm2/mm/memory.c 2006-04-17 17:25:50.000000000 -0700
@@ -434,7 +434,9 @@ copy_one_pte(struct mm_struct *dst_mm, s
/* pte contains position in swap or file, so copy. */
if (unlikely(!pte_present(pte))) {
if (!pte_file(pte)) {
- swap_duplicate(pte_to_swp_entry(pte));
+ swp_entry_t entry = pte_to_swp_entry(pte);
+
+ swap_duplicate(entry);
/* make sure dst_mm is on swapoff's mmlist. */
if (unlikely(list_empty(&dst_mm->mmlist))) {
spin_lock(&mmlist_lock);
@@ -443,6 +445,19 @@ copy_one_pte(struct mm_struct *dst_mm, s
&src_mm->mmlist);
spin_unlock(&mmlist_lock);
}
+ if (is_migration_entry(entry) &&
+ is_cow_mapping(vm_flags)) {
+ page = migration_entry_to_page(entry);
+
+ /*
+ * COW mappings require pages in both parent
+ * and child to be set to read.
+ */
+ entry = make_migration_entry(page,
+ ` SWP_MIGRATION_READ);
+ pte = swp_entry_to_pte(entry);
+ set_pte_at(src_mm, addr, src_pte, pte);
+ }
}
goto out_set_pte;
}
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Stuff]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
[Linux Resources]
