[libvirt] [PATCHv7 01/18] docs, util: Refactor schemas and virresctrl to support optional cache

Wang Huaqiang posted 18 patches 5 years, 7 months ago
[libvirt] [PATCHv7 01/18] docs, util: Refactor schemas and virresctrl to support optional cache
Posted by Wang Huaqiang 5 years, 7 months ago
Refactor schemas and virresctrl to support optional <cache> element
in <cachetune>.

Later, the monitor entry will be introduced and to be placed
under <cachetune>. Either cache entry or monitor entry is
an optional element of <cachetune>.

An cachetune has no <cache> element is taking the default resource
allocating policy defined in '/sys/fs/resctrl/schemata'.

Signed-off-by: Wang Huaqiang <huaqiang.wang@intel.com>
---
 docs/formatdomain.html.in     |  4 ++--
 docs/schemas/domaincommon.rng |  4 ++--
 src/util/virresctrl.c         | 28 ++++++++++++++++++++++++++++
 3 files changed, 32 insertions(+), 4 deletions(-)

diff --git a/docs/formatdomain.html.in b/docs/formatdomain.html.in
index 8189959..b1651e3 100644
--- a/docs/formatdomain.html.in
+++ b/docs/formatdomain.html.in
@@ -943,8 +943,8 @@
         <dl>
           <dt><code>cache</code></dt>
           <dd>
-            This element controls the allocation of CPU cache and has the
-            following attributes:
+            This optional element controls the allocation of CPU cache and has
+            the following attributes:
             <dl>
               <dt><code>level</code></dt>
               <dd>
diff --git a/docs/schemas/domaincommon.rng b/docs/schemas/domaincommon.rng
index 099a949..5c533d6 100644
--- a/docs/schemas/domaincommon.rng
+++ b/docs/schemas/domaincommon.rng
@@ -956,7 +956,7 @@
             <attribute name="vcpus">
               <ref name='cpuset'/>
             </attribute>
-            <oneOrMore>
+            <zeroOrMore>
               <element name="cache">
                 <attribute name="id">
                   <ref name='unsignedInt'/>
@@ -980,7 +980,7 @@
                   </attribute>
                 </optional>
               </element>
-            </oneOrMore>
+            </zeroOrMore>
           </element>
         </zeroOrMore>
         <zeroOrMore>
diff --git a/src/util/virresctrl.c b/src/util/virresctrl.c
index 5d811a2..91bd341 100644
--- a/src/util/virresctrl.c
+++ b/src/util/virresctrl.c
@@ -234,6 +234,11 @@ virResctrlInfoMonFree(virResctrlInfoMonPtr mon)
  * in case there is no allocation for that particular cache allocation (level,
  * cache, ...) or memory allocation for particular node).
  *
+ * Allocation corresponding to root directory, /sys/fs/sysctrl/, defines the
+ * default resource allocating policy, which is created immediately after
+ * mounting, and owns all the tasks and cpus in the system. Cache or memory
+ * bandwidth resource will be shared for tasks in this allocation.
+ *
  * =====Cache allocation technology (CAT)=====
  *
  * Since one allocation can be made for caches on different levels, the first
@@ -2215,6 +2220,15 @@ virResctrlAllocDeterminePath(virResctrlAllocPtr alloc,
         return -1;
     }
 
+    /* If the allocation is empty, then the path will be SYSFS_RESCTRL_PATH */
+    if (virResctrlAllocIsEmpty(alloc)) {
+        if (!alloc->path &&
+            VIR_STRDUP(alloc->path, SYSFS_RESCTRL_PATH) < 0)
+            return -1;
+
+        return 0;
+    }
+
     if (!alloc->path &&
         virAsprintf(&alloc->path, "%s/%s-%s",
                     SYSFS_RESCTRL_PATH, machinename, alloc->id) < 0)
@@ -2248,6 +2262,11 @@ virResctrlAllocCreate(virResctrlInfoPtr resctrl,
     if (virResctrlAllocDeterminePath(alloc, machinename) < 0)
         return -1;
 
+    /* If the allocation is empty, then do not create directory in underlying
+     * resctrl file system */
+    if (virResctrlAllocIsEmpty(alloc))
+        return 0;
+
     if (virFileExists(alloc->path)) {
         virReportError(VIR_ERR_INTERNAL_ERROR,
                        _("Path '%s' for resctrl allocation exists"),
@@ -2302,6 +2321,11 @@ virResctrlAllocAddPID(virResctrlAllocPtr alloc,
     char *pidstr = NULL;
     int ret = 0;
 
+    /* If the allocation is empty, then it is impossible to add a PID to
+     * allocation  due to lacking of its 'tasks' file. Just return */
+    if (virResctrlAllocIsEmpty(alloc))
+        return 0;
+
     if (!alloc->path) {
         virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
                        _("Cannot add pid to non-existing resctrl allocation"));
@@ -2334,6 +2358,10 @@ virResctrlAllocRemove(virResctrlAllocPtr alloc)
 {
     int ret = 0;
 
+    /* No directory have ever been created. Just return */
+    if (virResctrlAllocIsEmpty(alloc))
+        return 0;
+
     if (!alloc->path)
         return 0;
 
-- 
2.7.4

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Re: [libvirt] [PATCHv7 01/18] docs, util: Refactor schemas and virresctrl to support optional cache
Posted by John Ferlan 5 years, 7 months ago

On 10/22/18 4:01 AM, Wang Huaqiang wrote:
> Refactor schemas and virresctrl to support optional <cache> element
> in <cachetune>.
> 
> Later, the monitor entry will be introduced and to be placed
> under <cachetune>. Either cache entry or monitor entry is
> an optional element of <cachetune>.
> 
> An cachetune has no <cache> element is taking the default resource
> allocating policy defined in '/sys/fs/resctrl/schemata'.
> 
> Signed-off-by: Wang Huaqiang <huaqiang.wang@intel.com>
> ---
>  docs/formatdomain.html.in     |  4 ++--
>  docs/schemas/domaincommon.rng |  4 ++--
>  src/util/virresctrl.c         | 28 ++++++++++++++++++++++++++++
>  3 files changed, 32 insertions(+), 4 deletions(-)
> 

[...]

> +    /* If the allocation is empty, then the path will be SYSFS_RESCTRL_PATH */
> +    if (virResctrlAllocIsEmpty(alloc)) {
> +        if (!alloc->path &&
> +            VIR_STRDUP(alloc->path, SYSFS_RESCTRL_PATH) < 0)
> +            return -1;
> +
> +        return 0;
> +    }
> +

Because of ...

>      if (!alloc->path &&
>          virAsprintf(&alloc->path, "%s/%s-%s",
>                      SYSFS_RESCTRL_PATH, machinename, alloc->id) < 0)

[...]

> @@ -2334,6 +2358,10 @@ virResctrlAllocRemove(virResctrlAllocPtr alloc)
>  {
>      int ret = 0;
>  
> +    /* No directory have ever been created. Just return */
> +    if (virResctrlAllocIsEmpty(alloc))
> +        return 0;

... the change to virResctrlAllocDeterminePath to fill in alloc->path
when virResctrlAllocIsEmpty to be a default path, this should be:

    if (STREQ_NULLABLE(alloc->path, SYSFS_RESCTRL_PATH))
       return 0;

or moved after the next check and the _NULLABLE removed.

Whether the AllocIsEmpty is true or not shouldn't be the bearing on
whether the directory created because of that

> +
>      if (!alloc->path)
>          return 0;
>  
> 

I can adjust for you, let me know; otherwise, things are fine for the

Reviewed-by: John Ferlan <jferlan@redhat.com>

John

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