[libvirt] [PATCH v2] vircgroupv1: add ifdef around cgroup code

Pavel Hrdina posted 1 patch 5 years, 6 months ago
Patches applied successfully (tree, apply log)
git fetch https://github.com/patchew-project/libvirt tags/patchew/1e794dc0fa3725e48f2f9f318ef30fdeef8c2613.1537965690.git.phrdina@redhat.com
src/util/vircgroup.c     |  5 -----
src/util/vircgrouppriv.h |  8 ++++++++
src/util/vircgroupv1.c   | 13 +++++++++++++
3 files changed, 21 insertions(+), 5 deletions(-)
[libvirt] [PATCH v2] vircgroupv1: add ifdef around cgroup code
Posted by Pavel Hrdina 5 years, 6 months ago
Cgroups are supported only on linux.

Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
---

changed in v2:
    - define moved to vircgrouppriv.h
    - fixed alternative virCgroupV1Register function

 src/util/vircgroup.c     |  5 -----
 src/util/vircgrouppriv.h |  8 ++++++++
 src/util/vircgroupv1.c   | 13 +++++++++++++
 3 files changed, 21 insertions(+), 5 deletions(-)

diff --git a/src/util/vircgroup.c b/src/util/vircgroup.c
index 23957c82c7..aae699db0e 100644
--- a/src/util/vircgroup.c
+++ b/src/util/vircgroup.c
@@ -66,11 +66,6 @@ VIR_LOG_INIT("util.cgroup");
 #define CGROUP_NB_TOTAL_CPU_STAT_PARAM 3
 #define CGROUP_NB_PER_CPU_STAT_PARAM   1
 
-#if defined(__linux__) && defined(HAVE_GETMNTENT_R) && \
-    defined(_DIRENT_HAVE_D_TYPE) && defined(_SC_CLK_TCK)
-# define VIR_CGROUP_SUPPORTED
-#endif
-
 VIR_ENUM_IMPL(virCgroupController, VIR_CGROUP_CONTROLLER_LAST,
               "cpu", "cpuacct", "cpuset", "memory", "devices",
               "freezer", "blkio", "net_cls", "perf_event",
diff --git a/src/util/vircgrouppriv.h b/src/util/vircgrouppriv.h
index c50a25f195..5a19f965c2 100644
--- a/src/util/vircgrouppriv.h
+++ b/src/util/vircgrouppriv.h
@@ -29,9 +29,17 @@
 #ifndef __VIR_CGROUP_PRIV_H__
 # define __VIR_CGROUP_PRIV_H__
 
+# include <dirent.h>
+# include <unistd.h>
+
 # include "vircgroup.h"
 # include "vircgroupbackend.h"
 
+# if defined(__linux__) && defined(HAVE_GETMNTENT_R) && \
+    defined(_DIRENT_HAVE_D_TYPE) && defined(_SC_CLK_TCK)
+#  define VIR_CGROUP_SUPPORTED
+# endif
+
 struct _virCgroupV1Controller {
     int type;
     char *mountPoint;
diff --git a/src/util/vircgroupv1.c b/src/util/vircgroupv1.c
index 62a6e5c448..a00dd06148 100644
--- a/src/util/vircgroupv1.c
+++ b/src/util/vircgroupv1.c
@@ -55,6 +55,8 @@ VIR_ENUM_IMPL(virCgroupV1Controller, VIR_CGROUP_CONTROLLER_LAST,
               "name=systemd");
 
 
+#ifdef VIR_CGROUP_SUPPORTED
+
 /* We're looking for at least one 'cgroup' fs mount,
  * which is *not* a named mount. */
 static bool
@@ -2099,3 +2101,14 @@ virCgroupV1Register(void)
 {
     virCgroupBackendRegister(&virCgroupV1Backend);
 }
+
+#else /* !VIR_CGROUP_SUPPORTED */
+
+void
+virCgroupV1Register(void)
+{
+    virReportSystemError(ENOSYS, "%s",
+                         _("Control groups not supported on this platform"));
+}
+
+#endif /* !VIR_CGROUP_SUPPORTED */
-- 
2.17.1

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Re: [libvirt] [PATCH v2] vircgroupv1: add ifdef around cgroup code
Posted by Ján Tomko 5 years, 6 months ago
On Wed, Sep 26, 2018 at 02:42:51PM +0200, Pavel Hrdina wrote:
>Cgroups are supported only on linux.
>

The commit message is sparse, doesn't mention neither the build fix
motivation, nor the other conditions for building the cgroup code.

>Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
>---
>
>changed in v2:
>    - define moved to vircgrouppriv.h
>    - fixed alternative virCgroupV1Register function
>

As pointed out in my review of v1:
https://www.redhat.com/archives/libvir-list/2018-September/msg01313.html
the tests are only guarded by #ifdef __linux__

I just tried removing the VIR_CGROUP_SUPPORTED constant on v4.7.0
and the cgrouptest fails. So any unreasonable linux platform already has
the tests failing.

> src/util/vircgroup.c     |  5 -----
> src/util/vircgrouppriv.h |  8 ++++++++
> src/util/vircgroupv1.c   | 13 +++++++++++++
> 3 files changed, 21 insertions(+), 5 deletions(-)
>
>diff --git a/src/util/vircgroup.c b/src/util/vircgroup.c
>index 23957c82c7..aae699db0e 100644
>--- a/src/util/vircgroup.c
>+++ b/src/util/vircgroup.c
>@@ -66,11 +66,6 @@ VIR_LOG_INIT("util.cgroup");
> #define CGROUP_NB_TOTAL_CPU_STAT_PARAM 3
> #define CGROUP_NB_PER_CPU_STAT_PARAM   1
>
>-#if defined(__linux__) && defined(HAVE_GETMNTENT_R) && \
>-    defined(_DIRENT_HAVE_D_TYPE) && defined(_SC_CLK_TCK)
>-# define VIR_CGROUP_SUPPORTED
>-#endif

So this is just an overly verbose way of saying
#if defined(__linux__) with the other conditions being leftovers from
when we tried to build parts of the file on non-Linux.

>-
> VIR_ENUM_IMPL(virCgroupController, VIR_CGROUP_CONTROLLER_LAST,
>               "cpu", "cpuacct", "cpuset", "memory", "devices",
>               "freezer", "blkio", "net_cls", "perf_event",
>diff --git a/src/util/vircgrouppriv.h b/src/util/vircgrouppriv.h
>index c50a25f195..5a19f965c2 100644
>--- a/src/util/vircgrouppriv.h
>+++ b/src/util/vircgrouppriv.h
>@@ -29,9 +29,17 @@
> #ifndef __VIR_CGROUP_PRIV_H__
> # define __VIR_CGROUP_PRIV_H__
>
>+# include <dirent.h>
>+# include <unistd.h>
>+
> # include "vircgroup.h"
> # include "vircgroupbackend.h"
>
>+# if defined(__linux__) && defined(HAVE_GETMNTENT_R) && \
>+    defined(_DIRENT_HAVE_D_TYPE) && defined(_SC_CLK_TCK)
>+#  define VIR_CGROUP_SUPPORTED
>+# endif
>+
> struct _virCgroupV1Controller {
>     int type;
>     char *mountPoint;
>diff --git a/src/util/vircgroupv1.c b/src/util/vircgroupv1.c
>index 62a6e5c448..a00dd06148 100644
>--- a/src/util/vircgroupv1.c
>+++ b/src/util/vircgroupv1.c
>@@ -55,6 +55,8 @@ VIR_ENUM_IMPL(virCgroupV1Controller, VIR_CGROUP_CONTROLLER_LAST,
>               "name=systemd");
>
>
>+#ifdef VIR_CGROUP_SUPPORTED

This can be just #ifdef __linux__
and we don't need to bother with the rest.

Jano

>+
> /* We're looking for at least one 'cgroup' fs mount,
>  * which is *not* a named mount. */
> static bool
>@@ -2099,3 +2101,14 @@ virCgroupV1Register(void)
> {
>     virCgroupBackendRegister(&virCgroupV1Backend);
> }
>+
>+#else /* !VIR_CGROUP_SUPPORTED */
>+
>+void
>+virCgroupV1Register(void)
>+{
>+    virReportSystemError(ENOSYS, "%s",
>+                         _("Control groups not supported on this platform"));
>+}
>+
>+#endif /* !VIR_CGROUP_SUPPORTED */
>-- 
>2.17.1
>
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