[Xen-changelog] [xen master] numa-sched: leave node-affinity alone if not in "auto" mode

[patchbot@xxxxxxx]

commit 67348c3ac700b8bc9147638c719c3035c5ef20f5
Author:     Dario Faggioli <dario.faggioli@xxxxxxxxxx>
AuthorDate: Tue Nov 12 10:54:28 2013 +0100
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Tue Nov 12 10:54:28 2013 +0100

    numa-sched: leave node-affinity alone if not in "auto" mode
    
    If the domain's NUMA node-affinity is being specified by the
    user/toolstack (instead of being automatically computed by Xen),
    we really should stick to that. This means domain_update_node_affinity()
    is wrong when it filters out some stuff from there even in "!auto"
    mode.
    
    This commit fixes that. Of course, this does not mean node-affinity
    is always honoured (e.g., a vcpu won't run on a pcpu of a different
    cpupool) but the necessary logic for taking into account all the
    possible situations lives in the scheduler code, where it belongs.
    
    What could happen without this change is that, under certain
    circumstances, the node-affinity of a domain may change when the
    user modifies the vcpu-affinity of the domain's vcpus. This, even
    if probably not a real bug, is at least something the user does
    not expect, so let's avoid it.
    
    Signed-off-by: Dario Faggioli <dario.faggioli@xxxxxxxxxx>
    Reviewed-by: George Dunlap <george.dunlap@xxxxxxxxxxxxx>
    Acked-by: Keir Fraser <keir@xxxxxxx>
---
 xen/common/domain.c |   28 +++++++++-------------------
 1 files changed, 9 insertions(+), 19 deletions(-)

diff --git a/xen/common/domain.c b/xen/common/domain.c
index 8c9b813..63c47e8 100644
--- a/xen/common/domain.c
+++ b/xen/common/domain.c
@@ -352,7 +352,6 @@ void domain_update_node_affinity(struct domain *d)
     cpumask_var_t cpumask;
     cpumask_var_t online_affinity;
     const cpumask_t *online;
-    nodemask_t nodemask = NODE_MASK_NONE;
     struct vcpu *v;
     unsigned int node;
 
@@ -374,28 +373,19 @@ void domain_update_node_affinity(struct domain *d)
         cpumask_or(cpumask, cpumask, online_affinity);
     }
 
+    /*
+     * If d->auto_node_affinity is true, the domain's node-affinity mask
+     * (d->node_affinity) is automaically computed from all the domain's
+     * vcpus' vcpu-affinity masks (the union of which we have just built
+     * above in cpumask). OTOH, if d->auto_node_affinity is false, we
+     * must leave the node-affinity of the domain alone.
+     */
     if ( d->auto_node_affinity )
     {
-        /* Node-affinity is automaically computed from all vcpu-affinities */
+        nodes_clear(d->node_affinity);
         for_each_online_node ( node )
             if ( cpumask_intersects(&node_to_cpumask(node), cpumask) )
-                node_set(node, nodemask);
-
-        d->node_affinity = nodemask;
-    }
-    else
-    {
-        /* Node-affinity is provided by someone else, just filter out cpus
-         * that are either offline or not in the affinity of any vcpus. */
-        nodemask = d->node_affinity;
-        for_each_node_mask ( node, d->node_affinity )
-            if ( !cpumask_intersects(&node_to_cpumask(node), cpumask) )
-                node_clear(node, nodemask);//d->node_affinity);
-
-        /* Avoid loosing track of node-affinity because of a bad
-         * vcpu-affinity has been specified. */
-        if ( !nodes_empty(nodemask) )
-            d->node_affinity = nodemask;
+                node_set(node, d->node_affinity);
     }
 
     sched_set_node_affinity(d, &d->node_affinity);
--
generated by git-patchbot for /home/xen/git/xen.git#master

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