From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752445Ab2LTBo1 (ORCPT ); Wed, 19 Dec 2012 20:44:27 -0500 Received: from mail-da0-f53.google.com ([209.85.210.53]:47595 "EHLO mail-da0-f53.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752129Ab2LTBoV (ORCPT ); Wed, 19 Dec 2012 20:44:21 -0500 Date: Wed, 19 Dec 2012 17:44:29 -0800 (PST) From: Hugh Dickins X-X-Sender: hugh@eggly.anvils To: Mel Gorman cc: Linus Torvalds , Andrew Morton , Ingo Molnar , Sasha Levin , Petr Holasek , linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: [PATCH] ksm: make rmap walks more scalable In-Reply-To: Message-ID: References: User-Agent: Alpine 2.00 (LNX 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The rmap walks in ksm.c are like those in rmap.c: they can safely be done with anon_vma_lock_read(). Signed-off-by: Hugh Dickins --- mm/ksm.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) --- 3.7+git/mm/ksm.c 2012-12-16 16:35:08.752441527 -0800 +++ linux/mm/ksm.c 2012-12-19 16:58:05.292145790 -0800 @@ -1624,7 +1624,7 @@ again: struct anon_vma_chain *vmac; struct vm_area_struct *vma; - anon_vma_lock_write(anon_vma); + anon_vma_lock_read(anon_vma); anon_vma_interval_tree_foreach(vmac, &anon_vma->rb_root, 0, ULONG_MAX) { vma = vmac->vma; @@ -1648,7 +1648,7 @@ again: if (!search_new_forks || !mapcount) break; } - anon_vma_unlock(anon_vma); + anon_vma_unlock_read(anon_vma); if (!mapcount) goto out; } @@ -1678,7 +1678,7 @@ again: struct anon_vma_chain *vmac; struct vm_area_struct *vma; - anon_vma_lock_write(anon_vma); + anon_vma_lock_read(anon_vma); anon_vma_interval_tree_foreach(vmac, &anon_vma->rb_root, 0, ULONG_MAX) { vma = vmac->vma; @@ -1697,11 +1697,11 @@ again: ret = try_to_unmap_one(page, vma, rmap_item->address, flags); if (ret != SWAP_AGAIN || !page_mapped(page)) { - anon_vma_unlock(anon_vma); + anon_vma_unlock_read(anon_vma); goto out; } } - anon_vma_unlock(anon_vma); + anon_vma_unlock_read(anon_vma); } if (!search_new_forks++) goto again; @@ -1731,7 +1731,7 @@ again: struct anon_vma_chain *vmac; struct vm_area_struct *vma; - anon_vma_lock_write(anon_vma); + anon_vma_lock_read(anon_vma); anon_vma_interval_tree_foreach(vmac, &anon_vma->rb_root, 0, ULONG_MAX) { vma = vmac->vma; @@ -1749,11 +1749,11 @@ again: ret = rmap_one(page, vma, rmap_item->address, arg); if (ret != SWAP_AGAIN) { - anon_vma_unlock(anon_vma); + anon_vma_unlock_read(anon_vma); goto out; } } - anon_vma_unlock(anon_vma); + anon_vma_unlock_read(anon_vma); } if (!search_new_forks++) goto again;