Il 09/05/2014 19:54, Eduardo Habkost ha scritto:
On Fri, May 09, 2014 at 04:29:49PM +0800, Hu Tao wrote:
On Thu, May 08, 2014 at 04:51:56PM +0200, Paolo Bonzini wrote:
Il 06/05/2014 11:27, Hu Tao ha scritto:
This series includes work on QOMifying the memory backends.
the idea is to delegate all properties of the memory backend to
a new QOM class hierarchy, in which the concrete classes
are hostmem-ram and hostmem-file. The backend is passed to the
machine via "-numa node,memdev=foo" where "foo" is the id of the
backend object.
Hello,
I noticed now that if you have the host-nodes property set Linux
requires you to set a policy other than "default" too. If you don't,
the mbind system call fails.
What about squashing something like this?
Paolo
diff --git a/backends/hostmem.c b/backends/hostmem.c
index d3f8476..a0a3111 100644
--- a/backends/hostmem.c
+++ b/backends/hostmem.c
@@ -299,12 +299,23 @@ host_memory_backend_memory_init(UserCreatable *uc, Error
**errp)
#ifdef CONFIG_NUMA
unsigned long maxnode = find_last_bit(backend->host_nodes, MAX_NODES);
+ unsigned policy = backend->policy;
+
+ /* Linux does not accept MPOL_DEFAULT with nonzero bitmap, but
+ * "-object memory-ram,size=128M,hostnodes=0,policy=bind" is a
+ * bit of a mouthful. So if the host_nodes bitmap is nonzero,
+ * pick the BIND policy.
Are we sure MPOL_BIND is a better default than MPOL_INTERLEAVE or
MPOL_PREFERRED?
Better than MPOL_PREFERRED, yes. Better than MPOL_INTERLEAVE, I am not
sure.
* If policy=default is set, it is always going to be MPOL_DEFAULT.
* If policy=bind is set, it is always going to be MPOL_BIND.
* if policy=preferred is set, it is always going to be MPOL_PREFERRED.
* If policy is omitted, it will be be MPOL_DEFAULT is host-nodes is
unset, and MPOL_BIND if host_nodes is set.
That's possible. Or we can just detect the case in
host_memory_backend_memory_init and provide a better error message than
just "Invalid argument" (aka EINVAL). We're always free to take an
error situation and make it non-error in the future, but the reverse
would be hard to do.
Paolo
