On 2/21/23 9:21 PM, Philippe Mathieu-Daudé wrote:
On 21/2/23 10:21, Gavin Shan wrote:
On 2/21/23 8:15 PM, Philippe Mathieu-Daudé wrote:
On 21/2/23 09:53, Gavin Shan wrote:
Linux kernel guest reports warning when two CPUs in one socket have
been associated with different NUMA nodes, using the following command
lines.
-smp 6,maxcpus=6,sockets=2,clusters=1,cores=3,threads=1 \
-numa node,nodeid=0,cpus=0-1,memdev=ram0 \
-numa node,nodeid=1,cpus=2-3,memdev=ram1 \
-numa node,nodeid=2,cpus=4-5,memdev=ram2 \
------------[ cut here ]------------
WARNING: CPU: 0 PID: 1 at kernel/sched/topology.c:2271
build_sched_domains+0x284/0x910
Modules linked in:
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.14.0-268.el9.aarch64 #1
pstate: 00400005 (nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : build_sched_domains+0x284/0x910
lr : build_sched_domains+0x184/0x910
sp : ffff80000804bd50
x29: ffff80000804bd50 x28: 0000000000000002 x27: 0000000000000000
x26: ffff800009cf9a80 x25: 0000000000000000 x24: ffff800009cbf840
x23: ffff000080325000 x22: ffff0000005df800 x21: ffff80000a4ce508
x20: 0000000000000000 x19: ffff000080324440 x18: 0000000000000014
x17: 00000000388925c0 x16: 000000005386a066 x15: 000000009c10cc2e
x14: 00000000000001c0 x13: 0000000000000001 x12: ffff00007fffb1a0
x11: ffff00007fffb180 x10: ffff80000a4ce508 x9 : 0000000000000041
x8 : ffff80000a4ce500 x7 : ffff80000a4cf920 x6 : 0000000000000001
x5 : 0000000000000001 x4 : 0000000000000007 x3 : 0000000000000002
x2 : 0000000000001000 x1 : ffff80000a4cf928 x0 : 0000000000000001
Call trace:
build_sched_domains+0x284/0x910
sched_init_domains+0xac/0xe0
sched_init_smp+0x48/0xc8
kernel_init_freeable+0x140/0x1ac
kernel_init+0x28/0x140
ret_from_fork+0x10/0x20
Fix it by preventing mutiple CPUs in one socket to be associated with
different NUMA nodes.
Reported-by: Yihuang Yu <yi...@redhat.com>
Signed-off-by: Gavin Shan <gs...@redhat.com>
---
hw/arm/virt.c | 37 +++++++++++++++++++++++++++++++++++++
1 file changed, 37 insertions(+)
diff --git a/hw/arm/virt.c b/hw/arm/virt.c
index ac626b3bef..e0af267c77 100644
--- a/hw/arm/virt.c
+++ b/hw/arm/virt.c
@@ -230,6 +230,39 @@ static bool cpu_type_valid(const char *cpu)
return false;
}
+static bool numa_state_valid(MachineState *ms)
+{
+ MachineClass *mc = MACHINE_GET_CLASS(ms);
+ NumaState *state = ms->numa_state;
+ const CPUArchIdList *possible_cpus = mc->possible_cpu_arch_ids(ms);
+ const CPUArchId *cpus = possible_cpus->cpus;
+ int len = possible_cpus->len, i, j;
+
+ if (!state || state->num_nodes <= 1 || len <= 1) {
+ return true;
+ }
+
+ for (i = 0; i < len; i++) {
+ for (j = i + 1; j < len; j++) {
+ if (cpus[i].props.has_socket_id &&
+ cpus[i].props.has_node_id &&
+ cpus[j].props.has_socket_id &&
+ cpus[j].props.has_node_id &&
+ cpus[i].props.socket_id == cpus[j].props.socket_id &&
+ cpus[i].props.node_id != cpus[j].props.node_id) {
+ error_report("CPU-%d and CPU-%d in socket-%ld have been "
+ "associated with node-%ld and node-%ld",
+ i, j, cpus[i].props.socket_id,
+ cpus[i].props.node_id,
+ cpus[j].props.node_id);
+ return false;
+ }
+ }
+ }
+
+ return true;
+}
+
static void create_randomness(MachineState *ms, const char *node)
{
struct {
@@ -2040,6 +2073,10 @@ static void machvirt_init(MachineState *machine)
exit(1);
}
+ if (!numa_state_valid(machine)) {
+ exit(1);
+ }
Why restrict to the virt machine?
We tried x86 machines and virt machine, but the issue isn't reproducible on x86
machines.
So I think it's machine or architecture specific issue. However, I believe
RiscV should
have similar issue because linux/drivers/base/arch_topology.c is shared by
ARM64 and RiscV.
x86 doesn't use the driver to populate its CPU topology.
Oh, I haven't thought about the other archs, I meant this seem a generic
issue which affects all (ARM) machines, so why restrict to the (ARM)
virt machine?
[Ccing Igor for comments]
Well, virt machine is the only concern to us for now. You're right that all
ARM64 and ARM machines
need this check and limitation. So the check needs to be done in the generic
path. The best way
I can figure out is like something below. The idea is to introduce a switch to
'struct NumaState'
and do the check in the generic path. The switch is turned on by individual
machines. Please let me
know if you have better ideas
- Add 'bool struct NumaState::has_strict_socket_mapping', which is 'false' by
default until
machine specific initialization function calls helper
set_numa_strict_socket_mapping(), for
example in hw/arm/virt.c::virt_instance_init().
- In numa_complete_configuration(), do the check to make sure the socket
doesn't cross over
the NUMA node boundary if 'bool struct NumaState::has_strict_socket_mapping'
is true.
Thanks,
Gavin
