From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Tue, 18 Apr 2006 09:42:12 +0900 From: KAMEZAWA Hiroyuki Subject: Re: [PATCH 5/5] Swapless V2: Revise main migration logic Message-Id: <20060418094212.3ece222f.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: References: <20060413235406.15398.42233.sendpatchset@schroedinger.engr.sgi.com> <20060413235432.15398.23912.sendpatchset@schroedinger.engr.sgi.com> <20060414101959.d59ac82d.kamezawa.hiroyu@jp.fujitsu.com> <20060414113455.15fd5162.kamezawa.hiroyu@jp.fujitsu.com> <20060415090639.dde469e8.kamezawa.hiroyu@jp.fujitsu.com> <20060417091830.bca60006.kamezawa.hiroyu@jp.fujitsu.com> <20060418090439.3e2f0df4.kamezawa.hiroyu@jp.fujitsu.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Christoph Lameter Cc: akpm@osdl.org, hugh@veritas.com, linux-kernel@vger.kernel.org, lee.schermerhorn@hp.com, linux-mm@kvack.org, taka@valinux.co.jp, marcelo.tosatti@cyclades.com List-ID: On Mon, 17 Apr 2006 17:27:48 -0700 (PDT) Christoph Lameter wrote: > 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. > I think okay. BTW, when copying mm, mm->mmap_sem is held. Is mm->mmap_sem is not held while page migraion now ? I'm sorry I can't catch up all changes. or Is this needed for lazy migration (migration-on-fault) ? -Kame > > > 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 > Signed-off-by: Christoph Lameter > > 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, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org