From cb1894016dbd5a776fcb86a7c0f00a898e7ba023 Mon Sep 17 00:00:00 2001

Message-Id: <cb1894016dbd5a776fcb86a7c0f00a898e7ba023@dist-git>

From: Michal Privoznik <mprivozn@redhat.com>

Date: Thu, 18 Sep 2014 14:39:58 +0200

Subject: [PATCH] qemu: Honor hugepages for UMA domains

https://bugzilla.redhat.com/show_bug.cgi?id=1135396

There are two ways how to tell qemu to use huge pages. The first one

is suitable for domains with NUMA nodes: the path to hugetlbfs mount

is appended to NUMA node definition on the command line. The second

one is suitable for UMA domains: here there's this global '-mem-path'

argument that accepts path to the hugetlbfs mount point. However, the

latter case was not used for all the cases that it should be. For

instance:

  <memoryBacking>

    <hugepages>

      <page size='2048' unit='KiB' nodeset='0'/>

    </hugepages>

  </memoryBacking>

didn't trigger the '-mem-path' so the huge pages - despite being

configured - were not used at all.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>

(cherry picked from commit 281f70013e9d6fff7f2d4b55f5133a837f023190)

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>

---

 src/qemu/qemu_command.c                            | 25 ++++++++++++++---

 .../qemuxml2argv-hugepages-pages5.args             |  7 +++++

 .../qemuxml2argv-hugepages-pages5.xml              | 32 ++++++++++++++++++++++

 tests/qemuxml2argvtest.c                           |  1 +

 4 files changed, 61 insertions(+), 4 deletions(-)

 create mode 100644 tests/qemuxml2argvdata/qemuxml2argv-hugepages-pages5.args

 create mode 100644 tests/qemuxml2argvdata/qemuxml2argv-hugepages-pages5.xml

diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c

index 45667d9..fb9c453 100644

--- a/src/qemu/qemu_command.c

+++ b/src/qemu/qemu_command.c

@@ -7685,7 +7685,7 @@ qemuBuildCommandLine(virConnectPtr conn,

     virCommandAddArg(cmd, "-m");

     def->mem.max_balloon = VIR_DIV_UP(def->mem.max_balloon, 1024) * 1024;

     virCommandAddArgFormat(cmd, "%llu", def->mem.max_balloon / 1024);

-    if (def->mem.nhugepages && !def->mem.hugepages[0].size) {

+    if (def->mem.nhugepages && (!def->cpu || !def->cpu->ncells)) {

         char *mem_path;

         if (!cfg->nhugetlbfs) {

@@ -7701,9 +7701,26 @@ qemuBuildCommandLine(virConnectPtr conn,

             goto error;

         }

-        if (!(mem_path = qemuGetDefaultHugepath(cfg->hugetlbfs,

-                                                cfg->nhugetlbfs)))

-            goto error;

+        if (def->mem.hugepages[0].size) {

+            for (j = 0; j < cfg->nhugetlbfs; j++) {

+                if (cfg->hugetlbfs[j].size == def->mem.hugepages[0].size)

+                    break;

+            }

+

+            if (j == cfg->nhugetlbfs) {

+                virReportError(VIR_ERR_INTERNAL_ERROR,

+                               _("Unable to find any usable hugetlbfs mount for %llu KiB"),

+                               def->mem.hugepages[0].size);

+                goto error;

+            }

+

+            if (!(mem_path = qemuGetHugepagePath(&cfg->hugetlbfs[j])))

+                goto error;

+        } else {

+            if (!(mem_path = qemuGetDefaultHugepath(cfg->hugetlbfs,

+                                                    cfg->nhugetlbfs)))

+                goto error;

+        }

         virCommandAddArgList(cmd, "-mem-prealloc", "-mem-path",

                              mem_path, NULL);

diff --git a/tests/qemuxml2argvdata/qemuxml2argv-hugepages-pages5.args b/tests/qemuxml2argvdata/qemuxml2argv-hugepages-pages5.args

new file mode 100644

index 0000000..0e0f35a

--- /dev/null

+++ b/tests/qemuxml2argvdata/qemuxml2argv-hugepages-pages5.args

@@ -0,0 +1,7 @@

+LC_ALL=C PATH=/bin HOME=/home/test USER=test LOGNAME=test QEMU_AUDIO_DRV=none \

+/usr/bin/qemu -S -M pc -m 1024 \

+-mem-prealloc \

+-mem-path /dev/hugepages2M/libvirt/qemu \

+-smp 2 -nographic \

+-monitor unix:/tmp/test-monitor,server,nowait -no-acpi -boot c -usb \

+-hda /dev/HostVG/QEMUGuest1 -net none -serial none -parallel none

diff --git a/tests/qemuxml2argvdata/qemuxml2argv-hugepages-pages5.xml b/tests/qemuxml2argvdata/qemuxml2argv-hugepages-pages5.xml

new file mode 100644

index 0000000..50a9cd8

--- /dev/null

+++ b/tests/qemuxml2argvdata/qemuxml2argv-hugepages-pages5.xml

@@ -0,0 +1,32 @@

+<domain type='qemu'>

+  <name>SomeDummyHugepagesGuest</name>

+  <uuid>ef1bdff4-27f3-4e85-a807-5fb4d58463cc</uuid>

+  <memory unit='KiB'>1048576</memory>

+  <currentMemory unit='KiB'>1048576</currentMemory>

+  <memoryBacking>

+    <hugepages>

+      <page size='2048' unit='KiB'/>

+    </hugepages>

+  </memoryBacking>

+  <vcpu placement='static'>2</vcpu>

+  <os>

+    <type arch='i686' machine='pc'>hvm</type>

+    <boot dev='hd'/>

+  </os>

+  <clock offset='utc'/>

+  <on_poweroff>destroy</on_poweroff>

+  <on_reboot>restart</on_reboot>

+  <on_crash>destroy</on_crash>

+  <devices>

+    <emulator>/usr/bin/qemu</emulator>

+    <disk type='block' device='disk'>

+      <source dev='/dev/HostVG/QEMUGuest1'/>

+      <target dev='hda' bus='ide'/>

+      <address type='drive' controller='0' bus='0' target='0' unit='0'/>

+    </disk>

+    <controller type='usb' index='0'/>

+    <controller type='ide' index='0'/>

+    <controller type='pci' index='0' model='pci-root'/>

+    <memballoon model='virtio'/>

+  </devices>

+</domain>

diff --git a/tests/qemuxml2argvtest.c b/tests/qemuxml2argvtest.c

index 3b5f31a..68fc01b 100644

--- a/tests/qemuxml2argvtest.c

+++ b/tests/qemuxml2argvtest.c

@@ -688,6 +688,7 @@ mymain(void)

             QEMU_CAPS_OBJECT_MEMORY_FILE);

     DO_TEST_FAILURE("hugepages-pages4", QEMU_CAPS_MEM_PATH,

             QEMU_CAPS_OBJECT_MEMORY_RAM, QEMU_CAPS_OBJECT_MEMORY_FILE);

+    DO_TEST("hugepages-pages5", QEMU_CAPS_MEM_PATH);

     DO_TEST("nosharepages", QEMU_CAPS_MACHINE_OPT, QEMU_CAPS_MEM_MERGE);

     DO_TEST("disk-cdrom", NONE);

     DO_TEST("disk-cdrom-network-http", QEMU_CAPS_KVM, QEMU_CAPS_DEVICE,

-- 

2.1.0