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

[Ján Tomko]

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 at 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
>
>--
>libvir-list mailing list
>libvir-list at redhat.com
>https://www.redhat.com/mailman/listinfo/libvir-list
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