On Fri, 2018-10-05 at 12:14 +0200, Michal Privoznik wrote:
> On 10/02/2018 10:44 AM, Pavel Hrdina wrote:
> > This enables to use both cgroup v1 and v2 at the same time together
> > with libvirt. It is supported by kernel and there is valid use-
> > case,
> > not all controllers are implemented in cgroup v2 so there might be
> > configurations where administrator would enable these missing
> > controllers in cgroup v1.
> >
> > Signed-off-by: Pavel Hrdina <phrdina@xxxxxxxxxx>
> > ---
> > src/util/vircgroup.c | 351 ++++++++++++++++++++++++++----
> > ------
> > src/util/vircgroupbackend.c | 20 ++
> > src/util/vircgroupbackend.h | 16 +-
> > src/util/vircgrouppriv.h | 2 +-
> > 4 files changed, 291 insertions(+), 98 deletions(-)
> >
> > diff --git a/src/util/vircgroup.c b/src/util/vircgroup.c
> > index dc249bfe33..4aec5f1bcf 100644
> > --- a/src/util/vircgroup.c
> > +++ b/src/util/vircgroup.c
> > @@ -228,6 +228,7 @@ virCgroupDetectMounts(virCgroupPtr group)
> > struct mntent entry;
> > char buf[CGROUP_MAX_VAL];
> > int ret = -1;
> > + size_t i;
> >
> > mounts = fopen("/proc/mounts", "r");
> > if (mounts == NULL) {
> > @@ -236,11 +237,14 @@ virCgroupDetectMounts(virCgroupPtr group)
> > }
> >
> > while (getmntent_r(mounts, &entry, buf, sizeof(buf)) != NULL)
> > {
> > - if (group->backend->detectMounts(group,
> > - entry.mnt_type,
> > - entry.mnt_opts,
> > - entry.mnt_dir) < 0) {
> > - goto cleanup;
> > + for (i = 0; i < VIR_CGROUP_BACKEND_TYPE_LAST; i++) {
> > + if (group->backends[i] &&
> > + group->backends[i]->detectMounts(group,
> > + entry.mnt_type,
> > + entry.mnt_opts,
> > + entry.mnt_dir) <
> > 0) {
> > + goto cleanup;
> > + }
> > }
> > }
> >
> > @@ -303,6 +307,7 @@ virCgroupDetectPlacement(virCgroupPtr group,
> > }
> >
> > while (fgets(line, sizeof(line), mapping) != NULL) {
> > + size_t i;
> > char *controllers = strchr(line, ':');
> > char *selfpath = controllers ? strchr(controllers + 1,
> > ':') : NULL;
> > char *nl = selfpath ? strchr(selfpath, '\n') : NULL;
> > @@ -317,9 +322,12 @@ virCgroupDetectPlacement(virCgroupPtr group,
> > controllers++;
> > selfpath++;
> >
> > - if (group->backend->detectPlacement(group, path,
> > controllers,
> > - selfpath) < 0) {
> > - goto cleanup;
> > + for (i = 0; i < VIR_CGROUP_BACKEND_TYPE_LAST; i++) {
> > + if (group->backends[i] &&
> > + group->backends[i]->detectPlacement(group, path,
> > controllers,
> > + selfpath) < 0)
> > {
> > + goto cleanup;
> > + }
>
> So a loop like this appears all over the patch:
>
> for (i = 0; i < VIR_CGROUP_BACKEND_TYPE_LAST; i++) {
> if (group->backends[i] &&
> group->backends[i]->cb();
> }
>
> I wonder if we should have wrappers around these chunks of code. But
> that could be saved as a follow up patch.
We already have a macro for something similar that could be expanded
and reused in all of those.
And, yes, I totally agree that it could be done as a follow-up patch.
>
> > }
> > }
> >
> > @@ -338,8 +346,9 @@ virCgroupDetect(virCgroupPtr group,
> > const char *path,
> > virCgroupPtr parent)
> > {
> > - int rc;
> > size_t i;
> > + bool backendAvailable = false;
> > + int controllersAvailable = 0;
> > virCgroupBackendPtr *backends = virCgroupBackendGetAll();
> >
> > VIR_DEBUG("group=%p controllers=%d path=%s parent=%p",
> > @@ -350,31 +359,40 @@ virCgroupDetect(virCgroupPtr group,
> >
> > for (i = 0; i < VIR_CGROUP_BACKEND_TYPE_LAST; i++) {
> > if (backends[i] && backends[i]->available()) {
> > - group->backend = backends[i];
> > - break;
> > + group->backends[i] = backends[i];
> > + backendAvailable = true;
>
> No need to remove the 'break'.
>
> > }
> > }
>
> ACK
>
>
> Michal
>
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