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From: Vlastimil Babka <vbabka@suse.cz>
To: Srikar Dronamraju <srikar@linux.vnet.ibm.com>,
	Joonsoo Kim <js1304@gmail.com>
Cc: Sachin Sant <sachinp@linux.vnet.ibm.com>,
	Michal Hocko <mhocko@kernel.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Linux Memory Management List <linux-mm@kvack.org>,
	Mel Gorman <mgorman@suse.de>,
	"Kirill A. Shutemov" <kirill@shutemov.name>,
	Andrew Morton <akpm@linux-foundation.org>,
	linuxppc-dev <linuxppc-dev@lists.ozlabs.org>,
	Christopher Lameter <cl@linux.com>,
	Joonsoo Kim <iamjoonsoo.kim@lge.com>,
	Kirill Tkhai <ktkhai@virtuozzo.com>,
	Michael Ellerman <mpe@ellerman.id.au>
Subject: Re: [PATCH 1/3] powerpc/numa: Set numa_node for all possible cpus
Date: Fri, 13 Mar 2020 12:38:45 +0100
Message-ID: <06be5908-9af6-2892-0333-e9558b2cf474@suse.cz> (raw)
In-Reply-To: <20200313110440.GA25144@linux.vnet.ibm.com>

On 3/13/20 12:04 PM, Srikar Dronamraju wrote:
>> I lost all the memory about it. :)
>> Anyway, how about this?
>> 
>> 1. make node_present_pages() safer
>> static inline node_present_pages(nid)
>> {
>> if (!node_online(nid)) return 0;
>> return (NODE_DATA(nid)->node_present_pages);
>> }
>> 
> 
> Yes this would help.

Looks good, yeah.

>> 2. make node_to_mem_node() safer for all cases
>> In ppc arch's mem_topology_setup(void)
>> for_each_present_cpu(cpu) {
>>  numa_setup_cpu(cpu);
>>  mem_node = node_to_mem_node(numa_mem_id());
>>  if (!node_present_pages(mem_node)) {
>>   _node_numa_mem_[numa_mem_id()] = first_online_node;
>>  }
>> }
>> 
> 
> But here as discussed above, we miss the case of possible but not present nodes.
> For such nodes, the above change may not update, resulting in they still
> having 0. And node 0 can be only possible but not present.

So is there other way to do the setup so that node_to_mem_node() returns an
online+present node when called for any possible node?


  reply index

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-11 11:02 [PATCH 0/3] Offline memoryless cpuless node 0 Srikar Dronamraju
2020-03-11 11:02 ` [PATCH 1/3] powerpc/numa: Set numa_node for all possible cpus Srikar Dronamraju
2020-03-11 11:57   ` Michal Hocko
2020-03-12  5:27     ` Srikar Dronamraju
2020-03-12  8:23       ` Sachin Sant
2020-03-12  9:30         ` Vlastimil Babka
2020-03-12 13:14           ` Srikar Dronamraju
2020-03-12 13:51             ` Vlastimil Babka
2020-03-12 16:13               ` Srikar Dronamraju
2020-03-12 16:41                 ` Vlastimil Babka
2020-03-13  9:47                   ` Joonsoo Kim
2020-03-13 11:04                     ` Srikar Dronamraju
2020-03-13 11:38                       ` Vlastimil Babka [this message]
2020-03-16  8:15                         ` Joonsoo Kim
2020-03-13 11:22                   ` Srikar Dronamraju
2020-03-16  9:06                   ` Michal Hocko
2020-03-17 13:44                     ` Vlastimil Babka
2020-03-17 14:01                       ` Michal Hocko
2020-03-11 11:02 ` [PATCH 2/3] powerpc/numa: Prefer node id queried from vphn Srikar Dronamraju
2020-03-11 11:02 ` [PATCH 3/3] mm/page_alloc: Keep memoryless cpuless node 0 offline Srikar Dronamraju
2020-03-15 14:20   ` Christopher Lameter
2020-03-16  8:54     ` Michal Hocko
2020-03-18  7:50       ` Srikar Dronamraju
2020-03-18 18:57       ` Christopher Lameter

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