[libvirt] [PATCH] qemu: Allow system pages to <memoryBacking/>
Michal Privoznik
mprivozn at redhat.com
Fri Dec 12 10:05:37 UTC 2014
It occurred to me that OpenStack uses the following XML when not using
regular huge pages:
<memoryBacking>
<hugepages>
<page size='4' unit='KiB'/>
</hugepages>
</memoryBacking>
However, since we are expecting to see huge pages only, we fail to
startup the domain with following error:
libvirtError: internal error: Unable to find any usable hugetlbfs
mount for 4 KiB
While regular system pages are not huge pages technically, our code is
prepared for that and if it helps OpenStack (or other management
applications) we should cope with that.
Signed-off-by: Michal Privoznik <mprivozn at redhat.com>
---
src/qemu/qemu_command.c | 84 +++++++++++++---------
.../qemuxml2argv-hugepages-pages6.args | 4 ++
.../qemuxml2argv-hugepages-pages6.xml | 32 +++++++++
tests/qemuxml2argvtest.c | 1 +
4 files changed, 87 insertions(+), 34 deletions(-)
create mode 100644 tests/qemuxml2argvdata/qemuxml2argv-hugepages-pages6.args
create mode 100644 tests/qemuxml2argvdata/qemuxml2argv-hugepages-pages6.xml
diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c
index 48bdf4e..c44560f 100644
--- a/src/qemu/qemu_command.c
+++ b/src/qemu/qemu_command.c
@@ -6616,6 +6616,7 @@ qemuBuildNumaArgStr(virQEMUDriverConfigPtr cfg,
char *nodemask = NULL;
char *mem_path = NULL;
int ret = -1;
+ const long system_page_size = sysconf(_SC_PAGESIZE);
if (virDomainNumatuneHasPerNodeBinding(def->numatune) &&
!(virQEMUCapsGet(qemuCaps, QEMU_CAPS_OBJECT_MEMORY_RAM) ||
@@ -6626,7 +6627,8 @@ qemuBuildNumaArgStr(virQEMUDriverConfigPtr cfg,
goto cleanup;
}
- if (def->mem.nhugepages && def->mem.hugepages[0].size &&
+ if (def->mem.nhugepages &&
+ def->mem.hugepages[0].size != system_page_size &&
!virQEMUCapsGet(qemuCaps, QEMU_CAPS_OBJECT_MEMORY_FILE)) {
virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
_("huge pages per NUMA node are not "
@@ -6720,6 +6722,13 @@ qemuBuildNumaArgStr(virQEMUDriverConfigPtr cfg,
hugepage = master_hugepage;
}
+ if (hugepage && hugepage->size == system_page_size) {
+ /* However, if user specified to use "huge" page
+ * of regular system page size, it's as if they
+ * hasn't specified any huge pages at all. */
+ hugepage = NULL;
+ }
+
if (hugepage) {
/* Now lets see, if the huge page we want to use is even mounted
* and ready to use */
@@ -7882,44 +7891,51 @@ qemuBuildCommandLine(virConnectPtr conn,
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->cpu || !def->cpu->ncells)) {
- char *mem_path;
+ const long system_page_size = sysconf(_SC_PAGESIZE) / 1024;
+ char *mem_path = NULL;
- if (!cfg->nhugetlbfs) {
- virReportError(VIR_ERR_INTERNAL_ERROR,
- "%s", _("hugetlbfs filesystem is not mounted "
- "or disabled by administrator config"));
- goto error;
- }
- if (!virQEMUCapsGet(qemuCaps, QEMU_CAPS_MEM_PATH)) {
- virReportError(VIR_ERR_INTERNAL_ERROR,
- _("hugepage backing not supported by '%s'"),
- def->emulator);
- 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;
+ if (def->mem.hugepages[0].size == system_page_size) {
+ /* There is one special case: if user specified "huge"
+ * pages of regular system pages size. */
} else {
- if (!(mem_path = qemuGetDefaultHugepath(cfg->hugetlbfs,
- cfg->nhugetlbfs)))
+ if (!cfg->nhugetlbfs) {
+ virReportError(VIR_ERR_INTERNAL_ERROR,
+ "%s", _("hugetlbfs filesystem is not mounted "
+ "or disabled by administrator config"));
goto error;
+ }
+ if (!virQEMUCapsGet(qemuCaps, QEMU_CAPS_MEM_PATH)) {
+ virReportError(VIR_ERR_INTERNAL_ERROR,
+ _("hugepage backing not supported by '%s'"),
+ def->emulator);
+ 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);
+ virCommandAddArg(cmd, "-mem-prealloc");
+ if (mem_path)
+ virCommandAddArgList(cmd, "-mem-path", mem_path, NULL);
VIR_FREE(mem_path);
}
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-hugepages-pages6.args b/tests/qemuxml2argvdata/qemuxml2argv-hugepages-pages6.args
new file mode 100644
index 0000000..4eccb86
--- /dev/null
+++ b/tests/qemuxml2argvdata/qemuxml2argv-hugepages-pages6.args
@@ -0,0 +1,4 @@
+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 -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-pages6.xml b/tests/qemuxml2argvdata/qemuxml2argv-hugepages-pages6.xml
new file mode 100644
index 0000000..4f318fd
--- /dev/null
+++ b/tests/qemuxml2argvdata/qemuxml2argv-hugepages-pages6.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='4' 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 9e39068..bce88a8 100644
--- a/tests/qemuxml2argvtest.c
+++ b/tests/qemuxml2argvtest.c
@@ -713,6 +713,7 @@ mymain(void)
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("hugepages-pages6", NONE);
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,
--
2.0.4
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