From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Tue, 28 Oct 2008 09:25:31 -0500 (CDT) From: Christoph Lameter Subject: Re: [RFC][PATCH] lru_add_drain_all() don't use schedule_on_each_cpu() In-Reply-To: <20081027145509.ebffcf0e.akpm@linux-foundation.org> Message-ID: References: <2f11576a0810210851g6e0d86benef5d801871886dd7@mail.gmail.com> <2f11576a0810211018g5166c1byc182f1194cfdd45d@mail.gmail.com> <20081023235425.9C40.KOSAKI.MOTOHIRO@jp.fujitsu.com> <20081027145509.ebffcf0e.akpm@linux-foundation.org> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Sender: owner-linux-mm@kvack.org Return-Path: To: Andrew Morton Cc: KOSAKI Motohiro , heiko.carstens@de.ibm.com, npiggin@suse.de, linux-kernel@vger.kernel.org, hugh@veritas.com, torvalds@linux-foundation.org, riel@redhat.com, lee.schermerhorn@hp.com, linux-mm@kvack.org List-ID: On Mon, 27 Oct 2008, Andrew Morton wrote: > Can we fix that instead? How about this fix? Subject: Move migrate_prep out from under mmap_sem Move the migrate_prep outside the mmap_sem for the following system calls 1. sys_move_pages 2. sys_migrate_pages 3. sys_mbind() It really does not matter when we flush the lru. The system is free to add pages onto the lru even during migration which will make the page migration either skip the page (mbind, migrate_pages) or return a busy state (move_pages). Signed-off-by: Christoph Lameter Index: linux-2.6/mm/mempolicy.c =================================================================== --- linux-2.6.orig/mm/mempolicy.c 2008-10-28 09:16:18.475514878 -0500 +++ linux-2.6/mm/mempolicy.c 2008-10-28 09:22:46.486773874 -0500 @@ -489,12 +489,6 @@ int err; struct vm_area_struct *first, *vma, *prev; - if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)) { - - err = migrate_prep(); - if (err) - return ERR_PTR(err); - } first = find_vma(mm, start); if (!first) @@ -809,9 +803,13 @@ const nodemask_t *from_nodes, const nodemask_t *to_nodes, int flags) { int busy = 0; - int err = 0; + int err; nodemask_t tmp; + err = migrate_prep(); + if (err) + return err; + down_read(&mm->mmap_sem); err = migrate_vmas(mm, from_nodes, to_nodes, flags); @@ -974,6 +972,12 @@ start, start + len, mode, mode_flags, nmask ? nodes_addr(*nmask)[0] : -1); + if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)) { + + err = migrate_prep(); + if (err) + return err; + } down_write(&mm->mmap_sem); vma = check_range(mm, start, end, nmask, flags | MPOL_MF_INVERT, &pagelist); Index: linux-2.6/mm/migrate.c =================================================================== --- linux-2.6.orig/mm/migrate.c 2008-10-28 09:15:46.578013464 -0500 +++ linux-2.6/mm/migrate.c 2008-10-28 09:16:14.038014180 -0500 @@ -841,12 +841,12 @@ struct page_to_node *pp; LIST_HEAD(pagelist); + migrate_prep(); down_read(&mm->mmap_sem); /* * Build a list of pages to migrate */ - migrate_prep(); for (pp = pm; pp->node != MAX_NUMNODES; pp++) { struct vm_area_struct *vma; struct page *page; -- 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