[Xen-devel] [PATCH v4 7/7] libxl/vcpu-set - allow to decrease vcpu count on overcommitted guests (v5)

[Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>]

We have a check to warn the user if they are overcommitting.
But the check only checks the hosts CPU amount and does
not take into account the case when the user is trying to fix
the overcommit. That is - they want to limit the amount of
online VCPUs.

This fix allows the user to offline vCPUs without any
warnings when they are running an overcommitted guest.

Also fix the extra space in the message.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>

---
[v2: Remove crud code as spotted by Boris]
[v3: Moved crud code removal to another patch]
[v4: Remove the fprintf as it is done in libxl_domain_info]
[v5: Fix memory leak]
---
 tools/libxl/xl_cmdimpl.c | 17 +++++++++++++----
 1 file changed, 13 insertions(+), 4 deletions(-)

diff --git a/tools/libxl/xl_cmdimpl.c b/tools/libxl/xl_cmdimpl.c
index b121d75..648ca08 100644
--- a/tools/libxl/xl_cmdimpl.c
+++ b/tools/libxl/xl_cmdimpl.c
@@ -5238,12 +5238,21 @@ static int vcpuset(uint32_t domid, const char* 
nr_vcpus, int check_host)
      */
     if (check_host) {
         unsigned int host_cpu = libxl_get_max_cpus(ctx);
-        if (max_vcpus > host_cpu) {
-            fprintf(stderr, "You are overcommmitting! You have %d physical " \
-                    " CPUs and want %d vCPUs! Aborting, use --ignore-host to " 
\
-                    " continue\n", host_cpu, max_vcpus);
+        libxl_dominfo dominfo;
+
+        rc = libxl_domain_info(ctx, &dominfo, domid);
+        if (rc)
             return 1;
+
+        if (max_vcpus > dominfo.vcpu_online && max_vcpus > host_cpu) {
+            fprintf(stderr, "You are overcommmitting! You have %d physical" \
+                    " CPUs and want %d vCPUs! Aborting, use --ignore-host to" \
+                    " continue\n", host_cpu, max_vcpus);
+            rc = 1;
         }
+        libxl_dominfo_dispose(&dominfo);
+        if (rc)
+            return 1;
     }
     rc = libxl_cpu_bitmap_alloc(ctx, &cpumap, max_vcpus);
     if (rc) {
-- 
2.1.0


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