Messages in this thread Patch in this message | | | Date | Mon, 17 Apr 2006 17:27:48 -0700 (PDT) | From | Christoph Lameter <> | Subject | Re: [PATCH 5/5] Swapless V2: Revise main migration logic |
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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 <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Christoph Lameter <clameter@sgi.com>
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 majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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