10:12 a.m.
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(a)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 c84c7c3..26e166f 100644
--- a/src/qemu/qemu_command.c
+++ b/src/qemu/qemu_command.c
@@ -7540,7 +7540,7 @@ 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) {
@@ -7556,9 +7556,26 @@ 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 37aa571..ce109f9 100644
--- a/tests/qemuxml2argvtest.c
+++ b/tests/qemuxml2argvtest.c
@@ -683,6 +683,7 @@ mymain(void)
DO_TEST("hugepages-pages3", QEMU_CAPS_MEM_PATH,
QEMU_CAPS_OBJECT_MEMORY_RAM,
QEMU_CAPS_OBJECT_MEMORY_FILE);
DO_TEST_PARSE_ERROR("hugepages-pages4", NONE);
+ 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,
--
1.8.5.5