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[Qemu-devel] [PATCH v5 1/1] numa: Print warning if no node is assigned t
From: |
Eduardo Habkost |
Subject: |
[Qemu-devel] [PATCH v5 1/1] numa: Print warning if no node is assigned to a CPU |
Date: |
Thu, 19 Mar 2015 16:21:15 -0300 |
We need all possible CPUs (including hotplug ones) to be present in the
SRAT when QEMU starts. QEMU already does that correctly today, the only
problem is that when a CPU is omitted from the NUMA configuration, it is
silently assigned to node 0.
Check if all CPUs up to max_cpus are present in the NUMA configuration
and warn about missing CPUs.
Make it just a warning, to allow management software to be updated if
necessary. In the future we may make it a fatal error instead.
Command-line examples:
* Correct, no warning:
$ qemu-system-x86_64 -smp 2,maxcpus=4
$ qemu-system-x86_64 -smp 2,maxcpus=4 -numa node,cpus=0-3
* Incomplete, with warnings:
$ qemu-system-x86_64 -smp 2,maxcpus=4 -numa node,cpus=0
qemu-system-x86_64: warning: CPU(s) not present in any NUMA nodes: 1 2 3
qemu-system-x86_64: warning: All CPU(s) up to maxcpus should be described in
NUMA config
$ qemu-system-x86_64 -smp 2,maxcpus=4 -numa node,cpus=0-2
qemu-system-x86_64: warning: CPU(s) not present in any NUMA nodes: 3
qemu-system-x86_64: warning: All CPU(s) up to maxcpus should be described in
NUMA config
Signed-off-by: Eduardo Habkost <address@hidden>
---
v1 -> v2: (no changes)
v2 -> v3:
* Use enumerate_cpus() and error_report() for error message
* Simplify logic using bitmap_full()
v3 -> v4:
* Clarify error message, mention that all CPUs up to
maxcpus need to be described in NUMA config
v4 -> v5:
* Commit log update, to make problem description clearer
---
numa.c | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/numa.c b/numa.c
index fe74e1e..c975fb2 100644
--- a/numa.c
+++ b/numa.c
@@ -200,6 +200,16 @@ static void validate_numa_cpus(void)
bitmap_or(seen_cpus, seen_cpus,
numa_info[i].node_cpu, MAX_CPUMASK_BITS);
}
+
+ if (!bitmap_full(seen_cpus, max_cpus)) {
+ char *msg;
+ bitmap_complement(seen_cpus, seen_cpus, max_cpus);
+ msg = enumerate_cpus(seen_cpus, max_cpus);
+ error_report("warning: CPU(s) not present in any NUMA nodes: %s", msg);
+ error_report("warning: All CPU(s) up to maxcpus should be described "
+ "in NUMA config");
+ g_free(msg);
+ }
}
void parse_numa_opts(MachineClass *mc)
--
2.1.0