From 4e2265af50edd9b7772750a534310f87ba76e071 Mon Sep 17 00:00:00 2001

Message-Id: <4e2265af50edd9b7772750a534310f87ba76e071@dist-git>

From: John Ferlan <jferlan@redhat.com>

Date: Thu, 18 Sep 2014 09:29:54 -0400

Subject: [PATCH] qemu: Allow pinning specific IOThreads to a CPU

https://bugzilla.redhat.com/show_bug.cgi?id=1101574

Modify qemuProcessStart() in order to allowing setting affinity to

specific CPU's for IOThreads. The process followed is similar to

that for the vCPU's.

This involves adding a function to fetch the IOThread id's via

qemuMonitorGetIOThreads() and adding them to iothreadpids[] list.

Then making sure all the cgroup data has been properly set up and

finally assigning affinity.

(cherry picked from commit 9bef96ec502a01abde055233a8ab428a6824a4c0)

NOTE: Requires commit id 938fb12fad6d15c9fdb73f998c4e0ec1e278721f in order

      to build (next patch)

Signed-off-by: John Ferlan <jferlan@redhat.com>

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

---

 src/qemu/qemu_driver.c  |  8 ++++

 src/qemu/qemu_process.c | 98 +++++++++++++++++++++++++++++++++++++++++++++++++

 2 files changed, 106 insertions(+)

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

index 0a5605a..a1379c2 100644

--- a/src/qemu/qemu_driver.c

+++ b/src/qemu/qemu_driver.c

@@ -8766,6 +8766,14 @@ qemuDomainSetNumaParamsLive(virDomainObjPtr vm,

         virCgroupSetCpusetMems(priv->cgroup, nodeset_str) < 0)

         goto cleanup;

+    for (i = 0; i < priv->niothreadpids; i++) {

+        if (virCgroupNewIOThread(priv->cgroup, i, false, &cgroup_temp) < 0 ||

+            virCgroupSetCpusetMems(cgroup_temp, nodeset_str) < 0)

+            goto cleanup;

+        virCgroupFree(&cgroup_temp);

+    }

+

+

     ret = 0;

  cleanup:

     VIR_FREE(nodeset_str);

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

index bf1f0de..ed73ae5 100644

--- a/src/qemu/qemu_process.c

+++ b/src/qemu/qemu_process.c

@@ -2093,6 +2093,51 @@ qemuProcessDetectVcpuPIDs(virQEMUDriverPtr driver,

 }

+static int

+qemuProcessDetectIOThreadPIDs(virQEMUDriverPtr driver,

+                              virDomainObjPtr vm,

+                              int asyncJob)

+{

+    qemuDomainObjPrivatePtr priv = vm->privateData;

+    qemuMonitorIOThreadsInfoPtr *iothreads = NULL;

+    int niothreads = 0;

+    int ret = -1;

+    size_t i;

+

+    /* Get the list of IOThreads from qemu */

+    if (qemuDomainObjEnterMonitorAsync(driver, vm, asyncJob) < 0)

+        goto cleanup;

+    niothreads = qemuMonitorGetIOThreads(priv->mon, &iothreads);

+    qemuDomainObjExitMonitor(driver, vm);

+    if (niothreads <= 0)

+        goto cleanup;

+

+    if (niothreads != vm->def->iothreads) {

+        virReportError(VIR_ERR_INTERNAL_ERROR,

+                       _("got wrong number of IOThread pids from QEMU monitor. "

+                         "got %d, wanted %d"),

+                       niothreads, vm->def->iothreads);

+        goto cleanup;

+    }

+

+    if (VIR_ALLOC_N(priv->iothreadpids, niothreads) < 0)

+        goto cleanup;

+    priv->niothreadpids = niothreads;

+

+    for (i = 0; i < priv->niothreadpids; i++)

+        priv->iothreadpids[i] = iothreads[i]->thread_id;

+

+    ret = 0;

+

+ cleanup:

+    if (iothreads) {

+        for (i = 0; i < niothreads; i++)

+            qemuMonitorIOThreadsInfoFree(iothreads[i]);

+        VIR_FREE(iothreads);

+    }

+    return ret;

+}

+

 /* Helper to prepare cpumap for affinity setting, convert

  * NUMA nodeset into cpuset if @nodemask is not NULL, otherwise

  * just return a new allocated bitmap.

@@ -2285,6 +2330,41 @@ qemuProcessSetEmulatorAffinity(virDomainObjPtr vm)

     return ret;

 }

+/* Set CPU affinities for IOThreads threads. */

+static int

+qemuProcessSetIOThreadsAffinity(virDomainObjPtr vm)

+{

+    qemuDomainObjPrivatePtr priv = vm->privateData;

+    virDomainDefPtr def = vm->def;

+    virDomainVcpuPinDefPtr pininfo;

+    size_t i;

+    int ret = -1;

+

+    if (!def->cputune.niothreadspin)

+        return 0;

+

+    if (priv->iothreadpids == NULL) {

+        virReportError(VIR_ERR_OPERATION_INVALID,

+                       "%s", _("IOThread affinity is not supported"));

+        return -1;

+    }

+

+    for (i = 0; i < def->iothreads; i++) {

+        /* set affinity only for existing vcpus */

+        if (!(pininfo = virDomainVcpuPinFindByVcpu(def->cputune.iothreadspin,

+                                                   def->cputune.niothreadspin,

+                                                   i+1)))

+            continue;

+

+        if (virProcessSetAffinity(priv->iothreadpids[i], pininfo->cpumask) < 0)

+            goto cleanup;

+    }

+    ret = 0;

+

+ cleanup:

+    return ret;

+}

+

 static int

 qemuProcessInitPasswords(virConnectPtr conn,

                          virQEMUDriverPtr driver,

@@ -4411,6 +4491,10 @@ int qemuProcessStart(virConnectPtr conn,

     if (qemuProcessDetectVcpuPIDs(driver, vm, asyncJob) < 0)

         goto cleanup;

+    VIR_DEBUG("Detecting IOThread PIDs");

+    if (qemuProcessDetectIOThreadPIDs(driver, vm, asyncJob) < 0)

+        goto cleanup;

+

     VIR_DEBUG("Setting cgroup for each VCPU (if required)");

     if (qemuSetupCgroupForVcpu(vm) < 0)

         goto cleanup;

@@ -4419,6 +4503,10 @@ int qemuProcessStart(virConnectPtr conn,

     if (qemuSetupCgroupForEmulator(driver, vm, nodemask) < 0)

         goto cleanup;

+    VIR_DEBUG("Setting cgroup for each IOThread (if required)");

+    if (qemuSetupCgroupForIOThreads(vm) < 0)

+        goto cleanup;

+

     VIR_DEBUG("Setting VCPU affinities");

     if (qemuProcessSetVcpuAffinities(vm) < 0)

         goto cleanup;

@@ -4427,6 +4515,10 @@ int qemuProcessStart(virConnectPtr conn,

     if (qemuProcessSetEmulatorAffinity(vm) < 0)

         goto cleanup;

+    VIR_DEBUG("Setting affinity of IOThread threads");

+    if (qemuProcessSetIOThreadsAffinity(vm) < 0)

+        goto cleanup;

+

     VIR_DEBUG("Setting any required VM passwords");

     if (qemuProcessInitPasswords(conn, driver, vm, asyncJob) < 0)

         goto cleanup;

@@ -4842,6 +4934,8 @@ void qemuProcessStop(virQEMUDriverPtr driver,

     virDomainObjSetState(vm, VIR_DOMAIN_SHUTOFF, reason);

     VIR_FREE(priv->vcpupids);

     priv->nvcpupids = 0;

+    VIR_FREE(priv->iothreadpids);

+    priv->niothreadpids = 0;

     virObjectUnref(priv->qemuCaps);

     priv->qemuCaps = NULL;

     VIR_FREE(priv->pidfile);

@@ -5034,6 +5128,10 @@ int qemuProcessAttach(virConnectPtr conn ATTRIBUTE_UNUSED,

     if (qemuProcessDetectVcpuPIDs(driver, vm, QEMU_ASYNC_JOB_NONE) < 0)

         goto error;

+    VIR_DEBUG("Detecting IOThread PIDs");

+    if (qemuProcessDetectIOThreadPIDs(driver, vm, QEMU_ASYNC_JOB_NONE) < 0)

+        goto error;

+

     /* If we have -device, then addresses are assigned explicitly.

      * If not, then we have to detect dynamic ones here */

     if (!virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_DEVICE)) {

-- 

2.1.0