From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755143AbZFSIT4 (ORCPT ); Fri, 19 Jun 2009 04:19:56 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751547AbZFSITl (ORCPT ); Fri, 19 Jun 2009 04:19:41 -0400 Received: from hera.kernel.org ([140.211.167.34]:42349 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751498AbZFSITk (ORCPT ); Fri, 19 Jun 2009 04:19:40 -0400 Message-ID: <4A3B49BA.40100@kernel.org> Date: Fri, 19 Jun 2009 01:18:02 -0700 From: Yinghai Lu User-Agent: Thunderbird 2.0.0.19 (X11/20081227) MIME-Version: 1.0 To: Nathan Lynch CC: Christoph Lameter , Andrew Morton , mingo@elte.hu, mel@csn.ul.ie, tglx@linutronix.de, hpa@zytor.com, suresh.b.siddha@intel.com, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk, rusty@rustcorp.com.au, steiner@sgi.com, rientjes@google.com, containers@lists.linux-foundation.org Subject: Re: [PATCH] mm: clear N_HIGH_MEMORY map before se set it again -v4 References: <4A05269D.8000701@kernel.org> <20090512111623.GG25923@csn.ul.ie> <4A0A64FB.4080504@kernel.org> <20090513145950.GB28097@csn.ul.ie> <4A0C4910.7090508@kernel.org> <4A0C4A2A.6080009@kernel.org> <20090514095414.ba8356e5.akpm@linux-foundation.org> <4A0C4F67.5080802@kernel.org> <20090514102554.b3a36f19.akpm@linux-foundation.org> <4A0C563A.3020100@kernel.org> <4A2758CB.9090404@kernel.org> <4A27FAD4.2010104@kernel.org> <4A2803D1.4070001@kernel.org> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Nathan Lynch wrote: > Yinghai Lu writes: >> SRAT tables may contains nodes of very small size. The arch code may >> decide to not activate such a node. However, currently the early boot code >> sets N_HIGH_MEMORY for such nodes. These nodes therefore seem to be active >> although these nodes have no present pages. >> >> for 64bit N_HIGH_MEMORY == N_NORMAL_MEMORY, so that works for 64 bit too >> >> v4: update description according to Christoph >> >> Signed-off-by: Yinghai Lu >> Tested-by: Jack Steiner >> Acked-by: Christoph Lameter >> >> --- >> mm/page_alloc.c | 5 +++++ >> 1 file changed, 5 insertions(+) >> >> Index: linux-2.6/mm/page_alloc.c >> =================================================================== >> --- linux-2.6.orig/mm/page_alloc.c >> +++ linux-2.6/mm/page_alloc.c >> @@ -4041,6 +4041,11 @@ void __init free_area_init_nodes(unsigne >> early_node_map[i].start_pfn, >> early_node_map[i].end_pfn); >> >> + /* >> + * find_zone_movable_pfns_for_nodes/early_calculate_totalpages init >> + * that node_mask, clear it at first >> + */ >> + nodes_clear(node_states[N_HIGH_MEMORY]); >> /* Initialise every node */ >> mminit_verify_pageflags_layout(); >> setup_nr_node_ids(); > > This patch breaks the cpuset.mems cgroup attribute on an i386 kvm guest. > > With v2.6.30: > > # uname -r > 2.6.30 > # cat /cgroup/cpuset.mems > 0 > # mkdir /cgroup/test > # for i in cpus mems ; do cat /cgroup/cpuset.$i > /cgroup/test/cpuset.$i ; done > # echo $$ > /cgroup/test/tasks > # echo $? > 0 > > With a pulled-today Linus tree: > > # uname -r > 2.6.30-06725-g1d89b30 > # cat /cgroup/cpuset.mems > > # mkdir /cgroup/test > # for i in cpus mems ; do cat /cgroup/cpuset.$i > /cgroup/test/cpuset.$i ; done > # echo $$ > /cgroup/test/tasks > -bash: echo: write error: No space left on device > > (Note that in addition to the ENOSPC error, /cgroup/cpuset.mems is empty > rather than '0' in the second test.) > > I bisected to the commit containing this change. Reverting fixes the > problem. > can you use following patch to see what happens to that nodemask? YH diff --git a/mm/page_alloc.c b/mm/page_alloc.c index a5f3c27..eb89e8b 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -4189,6 +4189,7 @@ void __init free_area_init_nodes(unsigned long *max_zone_pfn) { unsigned long nid; int i; + char buf[512]; /* Sort early_node_map as initialisation assumes it is sorted */ sort_node_map(); @@ -4244,6 +4245,9 @@ void __init free_area_init_nodes(unsigned long *max_zone_pfn) * find_zone_movable_pfns_for_nodes/early_calculate_totalpages init * that node_mask, clear it at first */ + memset(buf, 0, 512); + nodemask_scnprintf(buf, 512, node_states[N_HIGH_MEMORY]); + printk(KERN_DEBUG "before clear: node_states [%d]: %s\n", N_HIGH_MEMORY, buf); nodes_clear(node_states[N_HIGH_MEMORY]); /* Initialise every node */ mminit_verify_pageflags_layout(); @@ -4258,6 +4262,9 @@ void __init free_area_init_nodes(unsigned long *max_zone_pfn) node_set_state(nid, N_HIGH_MEMORY); check_for_regular_memory(pgdat); } + memset(buf, 0, 512); + nodemask_scnprintf(buf, 512, node_states[N_HIGH_MEMORY]); + printk(KERN_DEBUG "after online check: node_states [%d]: %s\n", N_HIGH_MEMORY, buf); } static int __init cmdline_parse_core(char *p, unsigned long *core)