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: Fri, 7 Dec 2018 16:56:27 +0100	[thread overview]
Message-ID: <20181207155627.GG1286@dhcp22.suse.cz> (raw)
In-Reply-To: <CAFgQCTuu54oZWKq_ppEvZFb4Mz31gVmsa37gTap+e9KbE=T0aQ@mail.gmail.com>

On Fri 07-12-18 22:27:13, Pingfan Liu wrote:
[...]
> diff --git a/arch/x86/mm/numa.c b/arch/x86/mm/numa.c
> index 1308f54..4dc497d 100644
> --- a/arch/x86/mm/numa.c
> +++ b/arch/x86/mm/numa.c
> @@ -754,18 +754,23 @@ void __init init_cpu_to_node(void)
>  {
>         int cpu;
>         u16 *cpu_to_apicid = early_per_cpu_ptr(x86_cpu_to_apicid);
> +       int node, nr;
> 
>         BUG_ON(cpu_to_apicid == NULL);
> +       nr = cpumask_weight(cpu_possible_mask);
> +
> +       /* bring up all possible node, since dev->numa_node */
> +       //should check acpi works for node possible,
> +       for_each_node(node)
> +               if (!node_online(node))
> +                       init_memory_less_node(node);

I suspect there is no change if you replace for_each_node by
	for_each_node_mask(nid, node_possible_map)

here. If that is the case then we are probably calling
free_area_init_node too early. I do not see it yet though.
-- 
Michal Hocko
SUSE Labs