From mboxrd@z Thu Jan 1 00:00:00 1970 From: Johannes Weiner Subject: Re: mmotm 2015-01-22-15-04: qemu failure due to 'mm: memcontrol: remove unnecessary soft limit tree node test' Date: Fri, 23 Jan 2015 09:18:17 -0500 Message-ID: <20150123141817.GA22926@phnom.home.cmpxchg.org> References: <54c1822d.RtdGfWPekQVAw8Ly%akpm@linux-foundation.org> <20150123050802.GB22751@roeck-us.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: akpm@linux-foundation.org, mm-commits@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-next@vger.kernel.org, sfr@canb.auug.org.au, mhocko@suse.cz, cl@linux.com To: Guenter Roeck Return-path: Content-Disposition: inline In-Reply-To: <20150123050802.GB22751@roeck-us.net> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org Hi Guenter, CC'ing Christoph for slub-stuff: On Thu, Jan 22, 2015 at 09:08:02PM -0800, Guenter Roeck wrote: > On Thu, Jan 22, 2015 at 03:05:17PM -0800, akpm@linux-foundation.org wrote: > > The mm-of-the-moment snapshot 2015-01-22-15-04 has been uploaded to > > > > http://www.ozlabs.org/~akpm/mmotm/ > > > qemu test for ppc64 fails with > > Unable to handle kernel paging request for data at address 0x0000af50 > Faulting instruction address: 0xc00000000089d5d4 > Oops: Kernel access of bad area, sig: 11 [#1] > > with the following call stack: > > Call Trace: > [c00000003d32f920] [c00000000089d588] .__slab_alloc.isra.44+0x7c/0x6f4 > (unreliable) > [c00000003d32fa90] [c00000000020cf8c] .kmem_cache_alloc_node_trace+0x12c/0x3b0 > [c00000003d32fb60] [c000000000bceeb4] .mem_cgroup_init+0x128/0x1b0 > [c00000003d32fbf0] [c00000000000a2b4] .do_one_initcall+0xd4/0x260 > [c00000003d32fce0] [c000000000ba26a8] .kernel_init_freeable+0x244/0x32c > [c00000003d32fdb0] [c00000000000ac24] .kernel_init+0x24/0x140 > [c00000003d32fe30] [c000000000009564] .ret_from_kernel_thread+0x58/0x74 > > bisect log: [...] > # first bad commit: [a40d0d2cf21e2714e9a6c842085148c938bf36ab] mm: memcontrol: remove unnecessary soft limit tree node test The change in question is this: mm: memcontrol: remove unnecessary soft limit tree node test kzalloc_node() automatically falls back to nodes with suitable memory. Signed-off-by: Johannes Weiner Acked-by: Michal Hocko Reviewed-by: Vladimir Davydov Signed-off-by: Andrew Morton diff --git a/mm/memcontrol.c b/mm/memcontrol.c index fb9788af4a3e..10db4a654d68 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -4539,13 +4539,10 @@ static void __init mem_cgroup_soft_limit_tree_init(void) { struct mem_cgroup_tree_per_node *rtpn; struct mem_cgroup_tree_per_zone *rtpz; - int tmp, node, zone; + int node, zone; for_each_node(node) { - tmp = node; - if (!node_state(node, N_NORMAL_MEMORY)) - tmp = -1; - rtpn = kzalloc_node(sizeof(*rtpn), GFP_KERNEL, tmp); + rtpn = kzalloc_node(sizeof(*rtpn), GFP_KERNEL, node); BUG_ON(!rtpn); soft_limit_tree.rb_tree_per_node[node] = rtpn; -- Is the assumption of this patch wrong? Does the specified node have to be online for the fallback to work? Thanks