Re: [PATCH] mm/alloc: fallback to first node if the wanted node offline

From: Michal Hocko <mhocko@kernel.org>
To: Pingfan Liu <kernelfans@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	Andrew Morton <akpm@linux-foundation.org>,
	Mike Rapoport <rppt@linux.vnet.ibm.com>,
	Bjorn Helgaas <bhelgaas@google.com>,
	Jonathan Cameron <Jonathan.Cameron@huawei.com>
Subject: Re: [PATCH] mm/alloc: fallback to first node if the wanted node offline
Date: Thu, 20 Dec 2018 10:19:34 +0100	[thread overview]
Message-ID: <20181220091934.GC14234@dhcp22.suse.cz> (raw)
In-Reply-To: <CAFgQCTubm9B1_zM+oc1GLfOChu+XY9N4OcjyeDgk6ggObRtMKg@mail.gmail.com>

On Thu 20-12-18 15:19:39, Pingfan Liu wrote:
> Hi Michal,
> 
> WIth this patch applied on the old one, I got the following message.
> Please get it from attachment.
[...]
> [    0.409637] NUMA: Node 1 [mem 0x00000000-0x0009ffff] + [mem 0x00100000-0x7fffffff] -> [mem 0x00000000-0x7fffffff]
> [    0.419858] NUMA: Node 1 [mem 0x00000000-0x7fffffff] + [mem 0x100000000-0x47fffffff] -> [mem 0x00000000-0x47fffffff]
> [    0.430356] NODE_DATA(0) allocated [mem 0x87efd4000-0x87effefff]
> [    0.436325]     NODE_DATA(0) on node 5
> [    0.440092] Initmem setup node 0 [mem 0x0000000000000000-0x0000000000000000]
> [    0.447078] node[0] zonelist: 
> [    0.450106] NODE_DATA(1) allocated [mem 0x47ffd5000-0x47fffffff]
> [    0.456114] NODE_DATA(2) allocated [mem 0x87efa9000-0x87efd3fff]
> [    0.462064]     NODE_DATA(2) on node 5
> [    0.465852] Initmem setup node 2 [mem 0x0000000000000000-0x0000000000000000]
> [    0.472813] node[2] zonelist: 
> [    0.475846] NODE_DATA(3) allocated [mem 0x87ef7e000-0x87efa8fff]
> [    0.481827]     NODE_DATA(3) on node 5
> [    0.485590] Initmem setup node 3 [mem 0x0000000000000000-0x0000000000000000]
> [    0.492575] node[3] zonelist: 
> [    0.495608] NODE_DATA(4) allocated [mem 0x87ef53000-0x87ef7dfff]
> [    0.501587]     NODE_DATA(4) on node 5
> [    0.505349] Initmem setup node 4 [mem 0x0000000000000000-0x0000000000000000]
> [    0.512334] node[4] zonelist: 
> [    0.515370] NODE_DATA(5) allocated [mem 0x87ef28000-0x87ef52fff]
> [    0.521384] NODE_DATA(6) allocated [mem 0x87eefd000-0x87ef27fff]
> [    0.527329]     NODE_DATA(6) on node 5
> [    0.531091] Initmem setup node 6 [mem 0x0000000000000000-0x0000000000000000]
> [    0.538076] node[6] zonelist: 
> [    0.541109] NODE_DATA(7) allocated [mem 0x87eed2000-0x87eefcfff]
> [    0.547090]     NODE_DATA(7) on node 5
> [    0.550851] Initmem setup node 7 [mem 0x0000000000000000-0x0000000000000000]
> [    0.557836] node[7] zonelist: 

OK, so it is clear that building zonelists this early is not going to
fly. We do not have the complete information yet. I am not sure when do
we get that at this moment but I suspect the we either need to move that
initialization to a sooner stage or we have to reconsider whether the
phase when we build zonelists really needs to consider only online numa
nodes.

[...]
> [    1.067658] percpu: Embedded 46 pages/cpu @(____ptrval____) s151552 r8192 d28672 u262144
> [    1.075692] node[1] zonelist: 1:Normal 1:DMA32 1:DMA 5:Normal 
> [    1.081376] node[5] zonelist: 5:Normal 1:Normal 1:DMA32 1:DMA 

I hope to get to this before I leave for christmas vacation, if not I
will stare into it after then.

Thanks!
-- 
Michal Hocko
SUSE Labs