src: introduce hypervisor/domain_cgroup.c

There is duplicated code between virt drivers that needs to
be moved to avoid code repetition. In the case of duplicated
code between lxc_cgroup.c and qemu_cgroup.c a common place
would be utils/vircgroup.c. The problem is that this would
introduce /conf related definitions that shouldn't be imported
to vircgroup.c, which is supposed to be a place for utilitary
cgroups functions only. And syntax-check would forbid it anyway
due to cross-directory includes being used.

An alternative would be to overload domain_conf.c, which already
contains all the definitions required. But that file is already
crowded with XML handling code and we wouldn't do any favors to
it by putting more utilitary, non-XML parsing/formatting code
there.

In [1], Cole suggested a 'domain_cgroup' file to host common code
between lxc_cgroup and qemu_cgroup, and Daniel suggested a
'src/hypervisor' dir to host these type of files. This patch
introduces src/hypervisor/domain_cgroup.c and, to get started,
introduces a new virDomainCgroupSetupBlkio() function to host shared
code between virLXCCgroupSetupBlkioTune() and qemuSetupBlkioCgroup().

[1] https://www.redhat.com/archives/libvir-list/2019-December/msg00817.htmlSigned-off-by: NDaniel Henrique Barboza <danielhb413@gmail.com>
Signed-off-by: NJán Tomko <jtomko@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

src/Makefile.am

@@ -108,6 +108,7 @@ include locking/Makefile.inc.am
 include admin/Makefile.inc.am
 include rpc/Makefile.inc.am
 include test/Makefile.inc.am
+include hypervisor/Makefile.inc.am
 include esx/Makefile.inc.am
 include hyperv/Makefile.inc.am
 include vmx/Makefile.inc.am

src/hypervisor/Makefile.inc.am

+# vim: filetype=automake
+
+HYPERVISOR_SOURCES = \
+	hypervisor/domain_cgroup.h \
+	hypervisor/domain_cgroup.c \
+	$(NULL)
+
+noinst_LTLIBRARIES += libvirt_hypervisor.la
+libvirt_la_BUILT_LIBADD += libvirt_hypervisor.la
+libvirt_hypervisor_la_CFLAGS = \
+	-I$(srcdir)/conf \
+	$(AM_CFLAGS) \
+	$(NULL)
+libvirt_hypervisor_la_SOURCES = $(HYPERVISOR_SOURCES)

src/hypervisor/domain_cgroup.c

+/*
+ * domain_cgroup.c: cgroup functions shared between hypervisor drivers
+ *
+ * Copyright IBM Corp. 2020
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library.  If not, see
+ * <http://www.gnu.org/licenses/>.
+ */
+
+#include <config.h>
+
+#include "domain_cgroup.h"
+
+
+int
+virDomainCgroupSetupBlkio(virCgroupPtr cgroup, virDomainBlkiotune blkio)
+{
+    size_t i;
+
+    if (blkio.weight != 0 &&
+        virCgroupSetBlkioWeight(cgroup, blkio.weight) < 0)
+        return -1;
+
+    if (blkio.ndevices) {
+        for (i = 0; i < blkio.ndevices; i++) {
+            virBlkioDevicePtr dev = &blkio.devices[i];
+
+            if (dev->weight &&
+                virCgroupSetupBlkioDeviceWeight(cgroup, dev->path,
+                                                &dev->weight) < 0)
+                return -1;
+
+            if (dev->riops &&
+                virCgroupSetupBlkioDeviceReadIops(cgroup, dev->path,
+                                                  &dev->riops) < 0)
+                return -1;
+
+            if (dev->wiops &&
+                virCgroupSetupBlkioDeviceWriteIops(cgroup, dev->path,
+                                                   &dev->wiops) < 0)
+                return -1;
+
+            if (dev->rbps &&
+                virCgroupSetupBlkioDeviceReadBps(cgroup, dev->path,
+                                                 &dev->rbps) < 0)
+                return -1;
+
+            if (dev->wbps &&
+                virCgroupSetupBlkioDeviceWriteBps(cgroup, dev->path,
+                                                  &dev->wbps) < 0)
+                return -1;
+        }
+    }
+
+    return 0;
+}

src/hypervisor/domain_cgroup.h

+/*
+ * domain_cgroup.h: cgroup functions shared between hypervisor drivers
+ *
+ * Copyright IBM Corp. 2020
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library.  If not, see
+ * <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include "vircgroup.h"
+#include "domain_conf.h"
+
+
+int virDomainCgroupSetupBlkio(virCgroupPtr cgroup, virDomainBlkiotune blkio);

src/libvirt_private.syms

@@ -1390,6 +1390,10 @@ virSetConnectSecret;
 virSetConnectStorage;
 
 
+# hypervisor/domain_cgroup.h
+virDomainCgroupSetupBlkio;
+
+
 # libvirt_internal.h
 virConnectSupportsFeature;
 virDomainMigrateBegin3;

src/lxc/Makefile.inc.am

@@ -97,6 +97,7 @@ libvirt_driver_lxc_impl_la_CFLAGS = \
 	-I$(srcdir)/conf \
 	-I$(builddir)/lxc \
 	-I$(builddir)/rpc \
+	-I$(srcdir)/hypervisor \
 	$(AM_CFLAGS) \
 	$(NULL)
 libvirt_driver_lxc_impl_la_LIBADD = \
@@ -221,6 +222,7 @@ libvirt_lxc_CFLAGS = \
 	-I$(srcdir)/conf \
 	-I$(builddir)/lxc \
 	-I$(builddir)/rpc \
+	-I$(srcdir)/hypervisor \
 	$(AM_CFLAGS) \
 	$(PIE_CFLAGS) \
 	$(CAPNG_CFLAGS) \

src/lxc/lxc_cgroup.c

@@ -23,6 +23,7 @@
 
 #include "lxc_cgroup.h"
 #include "lxc_container.h"
+#include "domain_cgroup.h"
 #include "virfile.h"
 #include "virerror.h"
 #include "virlog.h"
@@ -101,44 +102,7 @@ static int virLXCCgroupSetupCpusetTune(virDomainDefPtr def,
 static int virLXCCgroupSetupBlkioTune(virDomainDefPtr def,
                                       virCgroupPtr cgroup)
 {
-    size_t i;
-
-    if (def->blkio.weight &&
-        virCgroupSetBlkioWeight(cgroup, def->blkio.weight) < 0)
-        return -1;
-
-    if (def->blkio.ndevices) {
-        for (i = 0; i < def->blkio.ndevices; i++) {
-            virBlkioDevicePtr dev = &def->blkio.devices[i];
-
-            if (dev->weight &&
-                virCgroupSetupBlkioDeviceWeight(cgroup, dev->path,
-                                                &dev->weight) < 0)
-                return -1;
-
-            if (dev->riops &&
-                virCgroupSetupBlkioDeviceReadIops(cgroup, dev->path,
-                                                  &dev->riops) < 0)
-                return -1;
-
-            if (dev->wiops &&
-                virCgroupSetupBlkioDeviceWriteIops(cgroup, dev->path,
-                                                   &dev->wiops) < 0)
-                return -1;
-
-            if (dev->rbps &&
-                virCgroupSetupBlkioDeviceReadBps(cgroup, dev->path,
-                                                 &dev->rbps) < 0)
-                return -1;
-
-            if (dev->wbps &&
-                virCgroupSetupBlkioDeviceWriteBps(cgroup, dev->path,
-                                                  &dev->wbps) < 0)
-                return -1;
-        }
-    }
-
-    return 0;
+    return virDomainCgroupSetupBlkio(cgroup, def->blkio);
 }
 
 

src/qemu/Makefile.inc.am

@@ -98,6 +98,7 @@ libvirt_driver_qemu_impl_la_CFLAGS = \
 	-I$(builddir)/access \
 	-I$(srcdir)/conf \
 	-I$(srcdir)/secret \
+	-I$(srcdir)/hypervisor \
 	$(AM_CFLAGS) \
 	$(NULL)
 libvirt_driver_qemu_impl_la_LDFLAGS = $(AM_LDFLAGS)

src/qemu/qemu_cgroup.c

@@ -30,6 +30,7 @@
 #include "viralloc.h"
 #include "virerror.h"
 #include "domain_audit.h"
+#include "domain_cgroup.h"
 #include "virscsi.h"
 #include "virstring.h"
 #include "virfile.h"
@@ -591,7 +592,6 @@ static int
 qemuSetupBlkioCgroup(virDomainObjPtr vm)
 {
     qemuDomainObjPrivatePtr priv = vm->privateData;
-    size_t i;
 
     if (!virCgroupHasController(priv->cgroup,
                                 VIR_CGROUP_CONTROLLER_BLKIO)) {
@@ -604,43 +604,7 @@ qemuSetupBlkioCgroup(virDomainObjPtr vm)
         }
     }
 
-    if (vm->def->blkio.weight != 0 &&
-        virCgroupSetBlkioWeight(priv->cgroup, vm->def->blkio.weight) < 0)
-        return -1;
-
-    if (vm->def->blkio.ndevices) {
-        for (i = 0; i < vm->def->blkio.ndevices; i++) {
-            virBlkioDevicePtr dev = &vm->def->blkio.devices[i];
-            virCgroupPtr cgroup = priv->cgroup;
-
-            if (dev->weight &&
-                virCgroupSetupBlkioDeviceWeight(cgroup, dev->path,
-                                                &dev->weight) < 0)
-                return -1;
-
-            if (dev->riops &&
-                virCgroupSetupBlkioDeviceReadIops(cgroup, dev->path,
-                                                  &dev->riops) < 0)
-                return -1;
-
-            if (dev->wiops &&
-                virCgroupSetupBlkioDeviceWriteIops(cgroup, dev->path,
-                                                   &dev->wiops) < 0)
-                return -1;
-
-            if (dev->rbps &&
-                virCgroupSetupBlkioDeviceReadBps(cgroup, dev->path,
-                                                 &dev->rbps) < 0)
-                return -1;
-
-            if (dev->wbps &&
-                virCgroupSetupBlkioDeviceWriteBps(cgroup, dev->path,
-                                                  &dev->wbps) < 0)
-                return -1;
-        }
-    }
-
-    return 0;
+    return virDomainCgroupSetupBlkio(priv->cgroup, vm->def->blkio);
 }