On 2017/12/11 20:03, Michal Hocko wrote:
> On Fri 01-12-17 18:13:52, zhong jiang wrote:
>> The acpi table are very much like user input. it is likely to
>> introduce some unreasonable node in some architecture. but
>> they do not ingore the node and bail out in time. it will result
>> in unnecessary print.
>> e.g x86: start is equal to end is a unreasonable node.
>> numa_blk_memblk will fails but return 0.
>>
>> meanwhile, Arm64 node will double set it to "numa_node_parsed"
>> after NUMA adds a memblk successfully. but X86 is not. because
>> numa_add_memblk is not set in X86.
> I am sorry but I still fail to understand wht the actual problem is.
> You said that x86 will print a message. Alright at least you know that
> the platform provides a nonsense ACPI/SRAT? tables and you can complain.
> But does the kernel misbehave? In what way?
From the view of the following code , we should expect that the node is
reasonable.
otherwise, if we only want to complain, it should bail out in time after
printing the
unreasonable message.
node_set(node, numa_nodes_parsed);
pr_info("SRAT: Node %u PXM %u [mem %#010Lx-%#010Lx]%s%s\n",
node, pxm,
(unsigned long long) start, (unsigned long long) end - 1,
hotpluggable ? " hotplug" : "",
ma->flags & ACPI_SRAT_MEM_NON_VOLATILE ? " non-volatile" : "");
/* Mark hotplug range in memblock. */
if (hotpluggable && memblock_mark_hotplug(start, ma->length))
pr_warn("SRAT: Failed to mark hotplug range [mem
%#010Lx-%#010Lx] in memblock\n",
(unsigned long long)start, (unsigned long long)end - 1);
max_possible_pfn = max(max_possible_pfn, PFN_UP(end - 1));
return 0;
out_err_bad_srat:
bad_srat();
In addition. Arm64 will double set node to numa_nodes_parsed after add a
memblk
successfully. Because numa_add_memblk will perform node_set(*, *).
if (numa_add_memblk(node, start, end) < 0) {
pr_err("SRAT: Failed to add memblk to node %u [mem
%#010Lx-%#010Lx]\n",
node, (unsigned long long) start,
(unsigned long long) end - 1);
goto out_err_bad_srat;
}
node_set(node, numa_nodes_parsed);
Thanks
zhong jiang
>> In view of the above problems. I think it need a better improvement.
>> we add a check here for bypassing the invalid memblk node.
>>
>> Signed-off-by: zhong jiang <zhongji...@huawei.com>
>> ---
>> arch/x86/mm/amdtopology.c | 1 -
>> arch/x86/mm/numa.c | 3 ++-
>> drivers/acpi/numa.c | 5 ++++-
>> 3 files changed, 6 insertions(+), 3 deletions(-)
>>
>> diff --git a/arch/x86/mm/amdtopology.c b/arch/x86/mm/amdtopology.c
>> index 91f501b..7657042 100644
>> --- a/arch/x86/mm/amdtopology.c
>> +++ b/arch/x86/mm/amdtopology.c
>> @@ -151,7 +151,6 @@ int __init amd_numa_init(void)
>>
>> prevbase = base;
>> numa_add_memblk(nodeid, base, limit);
>> - node_set(nodeid, numa_nodes_parsed);
>> }
>>
>> if (!nodes_weight(numa_nodes_parsed))
>> diff --git a/arch/x86/mm/numa.c b/arch/x86/mm/numa.c
>> index 25504d5..8f87f26 100644
>> --- a/arch/x86/mm/numa.c
>> +++ b/arch/x86/mm/numa.c
>> @@ -150,6 +150,8 @@ static int __init numa_add_memblk_to(int nid, u64 start,
>> u64 end,
>> mi->blk[mi->nr_blks].end = end;
>> mi->blk[mi->nr_blks].nid = nid;
>> mi->nr_blks++;
>> +
>> + node_set(nid, numa_nodes_parsed);
>> return 0;
>> }
>>
>> @@ -693,7 +695,6 @@ static int __init dummy_numa_init(void)
>> printk(KERN_INFO "Faking a node at [mem %#018Lx-%#018Lx]\n",
>> 0LLU, PFN_PHYS(max_pfn) - 1);
>>
>> - node_set(0, numa_nodes_parsed);
>> numa_add_memblk(0, 0, PFN_PHYS(max_pfn));
>>
>> return 0;
>> diff --git a/drivers/acpi/numa.c b/drivers/acpi/numa.c
>> index 917f1cc..f2e33cb 100644
>> --- a/drivers/acpi/numa.c
>> +++ b/drivers/acpi/numa.c
>> @@ -294,7 +294,9 @@ void __init acpi_numa_slit_init(struct acpi_table_slit
>> *slit)
>> goto out_err_bad_srat;
>> }
>>
>> - node_set(node, numa_nodes_parsed);
>> + /* some architecture is likely to ignore a unreasonable node */
>> + if (!node_isset(node, numa_nodes_parsed))
>> + goto out;
>>
>> pr_info("SRAT: Node %u PXM %u [mem %#010Lx-%#010Lx]%s%s\n",
>> node, pxm,
>> @@ -309,6 +311,7 @@ void __init acpi_numa_slit_init(struct acpi_table_slit
>> *slit)
>>
>> max_possible_pfn = max(max_possible_pfn, PFN_UP(end - 1));
>>
>> +out:
>> return 0;
>> out_err_bad_srat:
>> bad_srat();
>> --
>> 1.8.3.1
