Re: [libvirt] [PATCH 03/47] vircgroup: extract virCgroupV1Available

On Tue, Sep 18, 2018 at 5:45 PM, Pavel Hrdina <phrdina(a)redhat.com&gt; wrote: > Signed-off-by: Pavel Hrdina <phrdina(a)redhat.com&gt; > --- > src/util/vircgroup.c | 28 +++++++++------------------- > src/util/vircgroupbackend.h | 7 +++++++ > src/util/vircgroupv1.c | 35 +++++++++++++++++++++++++++++++++++ > 3 files changed, 51 insertions(+), 19 deletions(-) > > diff --git a/src/util/vircgroup.c b/src/util/vircgroup.c > index e85e0bde24..a5478a3fa4 100644 > --- a/src/util/vircgroup.c > +++ b/src/util/vircgroup.c > @@ -51,6 +51,7 @@ > > #include "virutil.h" > #include "viralloc.h" > +#include "vircgroupbackend.h" > #include "virerror.h" > #include "virlog.h" > #include "virfile.h" > @@ -64,8 +65,6 @@ > > VIR_LOG_INIT("util.cgroup"); > > -#define CGROUP_MAX_VAL 512 > - > #define VIR_FROM_THIS VIR_FROM_CGROUP > > #define CGROUP_NB_TOTAL_CPU_STAT_PARAM 3 > @@ -132,29 +131,20 @@ virCgroupGetDevicePermsString(int perms) > bool > virCgroupAvailable(void) > { > - bool ret = false; > - FILE *mounts = NULL; > - struct mntent entry; > - char buf[CGROUP_MAX_VAL]; > + size_t i; > + virCgroupBackendPtr *backends = virCgroupBackendGetAll(); > > - if (!virFileExists("/proc/cgroups")) > + if (!backends) > return false; > > - if (!(mounts = fopen("/proc/mounts", "r"))) > - return false; > - > - while (getmntent_r(mounts, &entry, buf, sizeof(buf)) != NULL) { > - /* We're looking for at least one 'cgroup' fs mount, > - * which is *not* a named mount. */ > - if (STREQ(entry.mnt_type, "cgroup") && > - !strstr(entry.mnt_opts, "name=")) { > - ret = true; > - break; > + for (i = 0; i < VIR_CGROUP_BACKEND_TYPE_LAST; i++) { > + if (backends[i] && backends[i]->available && > + backends[i]->available()) { > A little bit down in this patch I see the following comment about the "available" callback: /* Mandatory callbacks that need to be implemented for every backend. */ Considering this is part of the mandatory ones, do we really need to do the `backends[i]->available` check?