Add support for locking domain's memory pages

The following XML configuration can be used to request all domain's
memory pages to be kept locked in host's memory (i.e., domain's memory
pages will not be swapped out):

      <memoryBacking>
        <locked/>
      </memoryBacking>

diff --git a/docs/formatdomain.html.in b/docs/formatdomain.html.in
index c6c0728a4fcc8d9a6684eba25c976b055553306e..a71c4846715e75396b781425c1ca9d05e5c85158 100644 (file)
--- a/docs/formatdomain.html.in
+++ b/docs/formatdomain.html.in
@@ -595,22 +595,28 @@
   <memoryBacking>
     <hugepages/>
     <nosharepages/>
+    <locked/>
   </memoryBacking>
   ...
 </domain>
 </pre>
 
+    <p>The optional <code>memoryBacking</code> element may contain several
+      elements that influence how virtual memory pages are backed by host
+      pages.</p>
+
     <dl>
-      <dt><code>memoryBacking</code></dt>
-      <dd>The optional <code>memoryBacking</code> element has two
-        optional elements. The element <code>hugepages</code> tells
-        the hypervisor that the guest should have its memory allocated
-        using hugepages instead of the normal native page size. And the
-        optional element <code>nosharepages</code>
-        (<span class="since">since 1.0.6</span>) tells the hypervisor
-        that share pages (memory merge, KSM) should be disabled on guest
-        startup.
-      </dd>
+      <dt><code>hugepages</code></dt>
+      <dd>This tells the hypervisor that the guest should have its memory
+        allocated using hugepages instead of the normal native page size.</dd>
+      <dt><code>nosharepages</code></dt>
+      <dd>Instructs hypervisor to disable shared pages (memory merge, KSM) for
+        this domain. <span class="since">Since 1.0.6</span></dd>
+      <dt><code>locked</code></dt>
+      <dd>When set and supported by the hypervisor, memory pages belonging
+        to the domain will be locked in host's memory and the host will not
+        be allowed to swap them out.
+        <span class="since">Since 1.0.6</span></dd>
     </dl>
 
 

diff --git a/docs/schemas/domaincommon.rng b/docs/schemas/domaincommon.rng
index 8c7c1bcf016bc7bb4d6b0b346ffa5bb06aee02bd..018ca0b6beb99f674eff4270ea7d08b9cb134a0a 100644 (file)
--- a/docs/schemas/domaincommon.rng
+++ b/docs/schemas/domaincommon.rng
@@ -501,6 +501,11 @@
                 <empty/>
               </element>
             </optional>
+            <optional>
+              <element name="locked">
+                <empty/>
+              </element>
+            </optional>
           </interleave>
         </element>
       </optional>

diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c
index 11978dbe2e6efcfa40d540b5dcc53a5dc897a69c..b5e5d4d050d84e6393fb98f3bcf01cd44e43b6ac 100644 (file)
--- a/src/conf/domain_conf.c
+++ b/src/conf/domain_conf.c
@@ -10411,6 +10411,9 @@ virDomainDefParseXML(xmlDocPtr xml,
     if ((node = virXPathNode("./memoryBacking/nosharepages", ctxt)))
         def->mem.nosharepages = true;
 
+    if (virXPathBoolean("boolean(./memoryBacking/locked)", ctxt))
+        def->mem.locked = true;
+
     /* Extract blkio cgroup tunables */
     if (virXPathUInt("string(./blkiotune/weight)", ctxt,
                      &def->blkio.weight) < 0)
@@ -15766,17 +15769,16 @@ virDomainDefFormatInternal(virDomainDefPtr def,
         def->mem.swap_hard_limit)
         virBufferAddLit(buf, "  </memtune>\n");
 
-    if (def->mem.hugepage_backed || def->mem.nosharepages)
+    if (def->mem.hugepage_backed || def->mem.nosharepages || def->mem.locked) {
         virBufferAddLit(buf, "  <memoryBacking>\n");
-
-    if (def->mem.hugepage_backed)
-        virBufferAddLit(buf, "    <hugepages/>\n");
-
-    if (def->mem.nosharepages)
-        virBufferAddLit(buf, "    <nosharepages/>\n");
-
-    if (def->mem.hugepage_backed || def->mem.nosharepages)
+        if (def->mem.hugepage_backed)
+            virBufferAddLit(buf, "    <hugepages/>\n");
+        if (def->mem.nosharepages)
+            virBufferAddLit(buf, "    <nosharepages/>\n");
+        if (def->mem.locked)
+            virBufferAddLit(buf, "    <locked/>\n");
         virBufferAddLit(buf, "  </memoryBacking>\n");
+    }
 
     virBufferAddLit(buf, "  <vcpu");
     virBufferAsprintf(buf, " placement='%s'",

diff --git a/src/conf/domain_conf.h b/src/conf/domain_conf.h
index f40bfc64d3de27a110d1ab74d246303c8fdedf57..a10b2abd33e626e29a4e966ef7f586434056ea7b 100644 (file)
--- a/src/conf/domain_conf.h
+++ b/src/conf/domain_conf.h
@@ -1863,6 +1863,7 @@ struct _virDomainDef {
         unsigned long long cur_balloon; /* in kibibytes */
         bool hugepage_backed;
         bool nosharepages;
+        bool locked;
         int dump_core; /* enum virDomainMemDump */
         unsigned long long hard_limit; /* in kibibytes */
         unsigned long long soft_limit; /* in kibibytes */