lkml.org 
[lkml]   [2018]   [Dec]   [6]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
SubjectRe: [PATCH] mm/alloc: fallback to first node if the wanted node offline
On Thu 06-12-18 11:07:33, Pingfan Liu wrote:
> On Wed, Dec 5, 2018 at 5:40 PM Vlastimil Babka <vbabka@suse.cz> wrote:
> >
> > On 12/5/18 10:29 AM, Pingfan Liu wrote:
> > >> [ 0.007418] Early memory node ranges
> > >> [ 0.007419] node 1: [mem 0x0000000000001000-0x000000000008efff]
> > >> [ 0.007420] node 1: [mem 0x0000000000090000-0x000000000009ffff]
> > >> [ 0.007422] node 1: [mem 0x0000000000100000-0x000000005c3d6fff]
> > >> [ 0.007422] node 1: [mem 0x00000000643df000-0x0000000068ff7fff]
> > >> [ 0.007423] node 1: [mem 0x000000006c528000-0x000000006fffffff]
> > >> [ 0.007424] node 1: [mem 0x0000000100000000-0x000000047fffffff]
> > >> [ 0.007425] node 5: [mem 0x0000000480000000-0x000000087effffff]
> > >>
> > >> There is clearly no node2. Where did the driver get the node2 from?
> >
> > I don't understand these tables too much, but it seems the other nodes
> > exist without them:
> >
> > [ 0.007393] SRAT: PXM 2 -> APIC 0x20 -> Node 2
> >
> > Maybe the nodes are hotplugable or something?
> >
> I also not sure about it, and just have a hurry look at acpi spec. I
> will reply it on another email, and Cced some acpi guys about it
>
> > > Since using nr_cpus=4 , the node2 is not be instanced by x86 initalizing code.
> >
> > Indeed, nr_cpus seems to restrict what nodes we allocate and populate
> > zonelists for.
>
> Yes, in init_cpu_to_node(), since nr_cpus limits the possible cpu,
> which affects the loop for_each_possible_cpu(cpu) and skip the node2
> in this case.

THanks for pointing this out. It made my life easier. So It think the
bug is that we call init_memory_less_node from this path. I suspect
numa_register_memblks is the right place to do this. So I admit I
am not 100% sure but could you give this a try please?

diff --git a/arch/x86/mm/numa.c b/arch/x86/mm/numa.c
index 1308f5408bf7..4575ae4d5449 100644
--- a/arch/x86/mm/numa.c
+++ b/arch/x86/mm/numa.c
@@ -527,6 +527,19 @@ static void __init numa_clear_kernel_node_hotplug(void)
}
}

+static void __init init_memory_less_node(int nid)
+{
+ unsigned long zones_size[MAX_NR_ZONES] = {0};
+ unsigned long zholes_size[MAX_NR_ZONES] = {0};
+
+ free_area_init_node(nid, zones_size, 0, zholes_size);
+
+ /*
+ * All zonelists will be built later in start_kernel() after per cpu
+ * areas are initialized.
+ */
+}
+
static int __init numa_register_memblks(struct numa_meminfo *mi)
{
unsigned long uninitialized_var(pfn_align);
@@ -592,6 +605,8 @@ static int __init numa_register_memblks(struct numa_meminfo *mi)
continue;

alloc_node_data(nid);
+ if (!end)
+ init_memory_less_node(nid);
}

/* Dump memblock with node info and return. */
@@ -721,21 +736,6 @@ void __init x86_numa_init(void)
numa_init(dummy_numa_init);
}

-static void __init init_memory_less_node(int nid)
-{
- unsigned long zones_size[MAX_NR_ZONES] = {0};
- unsigned long zholes_size[MAX_NR_ZONES] = {0};
-
- /* Allocate and initialize node data. Memory-less node is now online.*/
- alloc_node_data(nid);
- free_area_init_node(nid, zones_size, 0, zholes_size);
-
- /*
- * All zonelists will be built later in start_kernel() after per cpu
- * areas are initialized.
- */
-}
-
/*
* Setup early cpu_to_node.
*
@@ -763,9 +763,6 @@ void __init init_cpu_to_node(void)
if (node == NUMA_NO_NODE)
continue;

- if (!node_online(node))
- init_memory_less_node(node);
-
numa_set_node(cpu, node);
}
}
--
Michal Hocko
SUSE Labs
\
 
 \ /
  Last update: 2018-12-06 09:28    [W:0.082 / U:9.016 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site