From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail144.messagelabs.com (mail144.messagelabs.com [216.82.254.51]) by kanga.kvack.org (Postfix) with ESMTP id 9F9746B0012 for ; Tue, 7 Jun 2011 06:19:05 -0400 (EDT) Date: Tue, 7 Jun 2011 11:18:57 +0100 From: Mel Gorman Subject: Re: [Bugme-new] [Bug 36192] New: Kernel panic when boot the 2.6.39+ kernel based off of 2.6.32 kernel Message-ID: <20110607101857.GM5247@suse.de> References: <20110530162904.b78bf354.kamezawa.hiroyu@jp.fujitsu.com> <20110530165453.845bba09.kamezawa.hiroyu@jp.fujitsu.com> <20110530175140.3644b3bf.kamezawa.hiroyu@jp.fujitsu.com> <20110606125421.GB30184@cmpxchg.org> <20110606144519.1e2e7d86.akpm@linux-foundation.org> <20110607084530.8ee571aa.kamezawa.hiroyu@jp.fujitsu.com> <20110607084530.GI5247@suse.de> <20110607174355.fde99297.kamezawa.hiroyu@jp.fujitsu.com> <20110607090900.GK5247@suse.de> <20110607183302.666115f1.kamezawa.hiroyu@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <20110607183302.666115f1.kamezawa.hiroyu@jp.fujitsu.com> Sender: owner-linux-mm@kvack.org List-ID: To: KAMEZAWA Hiroyuki Cc: Andrew Morton , Johannes Weiner , linux-mm@kvack.org, bugzilla-daemon@bugzilla.kernel.org, bugme-daemon@bugzilla.kernel.org, qcui@redhat.com, Daisuke Nishimura , Li Zefan On Tue, Jun 07, 2011 at 06:33:02PM +0900, KAMEZAWA Hiroyuki wrote: > On Tue, 7 Jun 2011 10:09:00 +0100 > Mel Gorman wrote: > > > I should have said "nodes" even though the end result is the same. The > > problem at the moment is cgroup initialisation is checking PFNs outside > > node boundaries. It should be ensuring that the start and end PFNs it > > uses are within boundaries. > > > Maybe you like this kind of fix. Yes, this can fix the problem on bugzilla. > My concern is this will not work for ARM. > > This patch (and all other patch) works on my test host. > == > make sparsemem's page_cgroup_init to be node aware. > > With sparsemem, page_cgroup_init scans pfn from 0 to max_pfn. > But this may scan a pfn which is not on any node and can access > memmap which is not initialized. > > This makes page_cgroup_init() for SPARSEMEM node aware. > > Signed-off-by: KAMEZAWA Hiroyuki > --- > mm/page_cgroup.c | 26 ++++++++++++++++++++++---- > 1 file changed, 22 insertions(+), 4 deletions(-) > > Index: linux-3.0-rc1/mm/page_cgroup.c > =================================================================== > --- linux-3.0-rc1.orig/mm/page_cgroup.c > +++ linux-3.0-rc1/mm/page_cgroup.c > @@ -285,14 +285,32 @@ void __init page_cgroup_init(void) > { > unsigned long pfn; > int fail = 0; > + int node; > > if (mem_cgroup_disabled()) > return; > > - for (pfn = 0; !fail && pfn < max_pfn; pfn += PAGES_PER_SECTION) { > - if (!pfn_present(pfn)) > - continue; > - fail = init_section_page_cgroup(pfn); > + for_each_node_state(node, N_HIGH_MEMORY) { > + unsigned long start_pfn, end_pfn; > + > + start_pfn = NODE_DATA(node)->node_start_pfn; > + end_pfn = start_pfn + NODE_DATA(node)->node_spanned_pages; > + /* > + * This calculation makes sure that this nid detection for > + * section can work even if node->start_pfn is not aligned to > + * section. For sections on not-node-boundary, we see head > + * page of sections. > + */ > + for (pfn = start_pfn; > + !fail & (pfn < end_pfn); && instead of & there? > + pfn = ALIGN(pfn + PAGES_PER_SECTION, PAGES_PER_SECTION)) { > + if (!pfn_present(pfn)) > + continue; > + /* Nodes can be overlapped */ > + if (pfn_to_nid(pfn) != node) > + continue; > + fail = init_section_page_cgroup(pfn); > + } So this is finding the first valid PFN in a node. Even the overlapping problem should not be an issue here as unless node memory initialisation is overwriting flags belonging to other nodes. The paranoia does not hurt. I also don't think the ARM punching holes in the memmap is a problem because we'd at least expect the start of the node to be valid. -- Mel Gorman SUSE Labs -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org