This patch introduced a bug and broke the 'resctrl' feature.
It introduced a 'divide by zero' error if you defined any 'resctrl'
allocation group through <cputune/cachetune/cache>.
Reason is 'caps->resctrl' is fully initialized through two steps,
'virResctrlInfoNew'
invokes 'virResctrlGetInfo' completes the first step, later,
'virResctrlInfoGetCache'
accomplishes the filling of
'caps->resctrl->levels->types->control.granularity'.
The simplest way to fix the bug is drawback this patch, but still have
the undesirable
overhead.
Another way to fix but not that simple is moving the 'caps->host.cache'
object
into 'virresctrl'. If no one takes this task, I can do it and need some
days for it.
Br
Huaqiang
[PATCH 29/30] qemu: directly create virResctrlInfo ignoring
capabilities
From: Daniel P. Berrangé <berrange redhat com>
To: libvir-list redhat com
Subject: [PATCH 29/30] qemu: directly create virResctrlInfo
ignoring capabilities
Date: Wed, 4 Dec 2019 14:21:12 +0000
We always refresh the capabilities object when using virResctrlInfo
during process startup. This is undesirable overhead, because we can
just directly create a virResctrlInfo instead.
Signed-off-by: Daniel P. Berrangé <berrange redhat com>
---
src/qemu/qemu_process.c | 24 ++++++++----------------
src/util/virresctrl.h | 2 ++
2 files changed, 10 insertions(+), 16 deletions(-)
diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c
index 3a3860b1a3..2b35680abc 100644
--- a/src/qemu/qemu_process.c
+++ b/src/qemu/qemu_process.c
@@ -2724,29 +2724,24 @@ qemuProcessSetupEmulator(virDomainObjPtr vm)
static int
-qemuProcessResctrlCreate(virQEMUDriverPtr driver,
- virDomainObjPtr vm)
+qemuProcessResctrlCreate(virDomainObjPtr vm)
{
- int ret = -1;
size_t i = 0;
- virCapsPtr caps = NULL;
qemuDomainObjPrivatePtr priv = vm->privateData;
+ g_autoptr(virResctrlInfo) resctrl = NULL;
if (!vm->def->nresctrls)
return 0;
- /* Force capability refresh since resctrl info can change
- * XXX: move cache info into virresctrl so caps are not needed */
- caps = virQEMUDriverGetCapabilities(driver, true);
- if (!caps)
+ if (!(resctrl = virResctrlInfoNew()))
return -1;
for (i = 0; i < vm->def->nresctrls; i++) {
size_t j = 0;
- if (virResctrlAllocCreate(caps->host.resctrl,
+ if (virResctrlAllocCreate(resctrl,
vm->def->resctrls[i]->alloc,
priv->machineName) < 0)
- goto cleanup;
+ return -1;
for (j = 0; j < vm->def->resctrls[i]->nmonitors; j++) {
virDomainResctrlMonDefPtr mon = NULL;
@@ -2754,14 +2749,11 @@ qemuProcessResctrlCreate(virQEMUDriverPtr driver,
mon = vm->def->resctrls[i]->monitors[j];
if (virResctrlMonitorCreate(mon->instance,
priv->machineName) < 0)
- goto cleanup;
+ return -1;
}
}
- ret = 0;
- cleanup:
- virObjectUnref(caps);
- return ret;
+ return 0;
}
@@ -6882,7 +6874,7 @@ qemuProcessLaunch(virConnectPtr conn,
goto cleanup;
VIR_DEBUG("Setting up resctrl");
- if (qemuProcessResctrlCreate(driver, vm) < 0)
+ if (qemuProcessResctrlCreate(vm) < 0)
goto cleanup;
VIR_DEBUG("Setting up managed PR daemon");
diff --git a/src/util/virresctrl.h b/src/util/virresctrl.h
index 3dd7c96348..759320d0fd 100644
--- a/src/util/virresctrl.h
+++ b/src/util/virresctrl.h
@@ -100,6 +100,8 @@ typedef virResctrlInfo *virResctrlInfoPtr;
virResctrlInfoPtr
virResctrlInfoNew(void);
+G_DEFINE_AUTOPTR_CLEANUP_FUNC(virResctrlInfo, virObjectUnref);
+
int
virResctrlInfoGetCache(virResctrlInfoPtr resctrl,
unsigned int level,
--
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