On Thu, Aug 26, 2021 at 12:00:25PM +0200, Christian Brauner wrote:
> On Wed, Aug 25, 2021 at 07:06:13PM +0200, Eugene Syromiatnikov wrote:
> > Commit 7ac592aa35a684ff ("sched: prctl() core-scheduling interface")
> > made use of enum pid_type in prctl's arg4; this type and the associated
> > enumeration definitions are not exposed to userspace. Christian
> > has suggested to provide additional macro definitions that convey
> > the meaning of the type argument more in alignment with its actual
> > usage, and this patch does exactly that.
> >
> > Suggested-by: Christian Brauner <christian.brauner@xxxxxxxxxx>
> > Complements: 7ac592aa35a684ff ("sched: prctl() core-scheduling interface")
> > Signed-off-by: Eugene Syromiatnikov <esyr@xxxxxxxxxx>
> > ---
>
> I mean, I proposed the names so I'm ok with them. :)
> Acked-by: Christian Brauner <christian.brauner@xxxxxxxxxx>
>
> Peter et al. are you ok with this and do the names make sense to you?
I'll pick this up once the merge window closes then.
Thanks!
Christian
>
> Christian
>
> > v4:
> > - Rewritten in accordance with Christian Brauner's suggestion to provide
> > macro definitions that are explicitly tailored for the prctl op.
> >
> > v3: https://lore.kernel.org/lkml/20210807120905.GA14706@xxxxxxxxxxxxxxxxx/
> > - Fixed header guard macro: s/_UAPI_LINUX_PID_H/_UAPI_LINUX_PIDTYPE_H/,
> > as noted by Dmitry Levin.
> >
> > v2: https://lore.kernel.org/lkml/20210807104800.GA22620@xxxxxxxxxxxxxxxxx/
> > - Header file is renamed from pid.h to pidtype.h to avoid collisions
> > with include/linux/pid.h when included from uapi headers;
> > - The enum type has renamed from __kernel_pid_type to __kernel_pidtype
> > to avoid possible confusion with __kernel_pid_t.
> >
> > v1: https://lore.kernel.org/lkml/20210807010123.GA5174@xxxxxxxxxxxxxxxxx/
> > ---
> > Documentation/admin-guide/hw-vuln/core-scheduling.rst | 5 +++--
> > include/uapi/linux/prctl.h | 3 +++
> > kernel/sched/core_sched.c | 4 ++++
> > 3 files changed, 10 insertions(+), 2 deletions(-)
> >
> > diff --git a/Documentation/admin-guide/hw-vuln/core-scheduling.rst b/Documentation/admin-guide/hw-vuln/core-scheduling.rst
> > index 7b410ae..9a65fed 100644
> > --- a/Documentation/admin-guide/hw-vuln/core-scheduling.rst
> > +++ b/Documentation/admin-guide/hw-vuln/core-scheduling.rst
> > @@ -61,8 +61,9 @@ arg3:
> > ``pid`` of the task for which the operation applies.
> >
> > arg4:
> > - ``pid_type`` for which the operation applies. It is of type ``enum pid_type``.
> > - For example, if arg4 is ``PIDTYPE_TGID``, then the operation of this command
> > + ``pid_type`` for which the operation applies. It is one of
> > + ``PR_SCHED_CORE_SCOPE_``-prefixed macro constants. For example, if arg4
> > + is ``PR_SCHED_CORE_SCOPE_THREAD_GROUP``, then the operation of this command
> > will be performed for all tasks in the task group of ``pid``.
> >
> > arg5:
> > diff --git a/include/uapi/linux/prctl.h b/include/uapi/linux/prctl.h
> > index 967d9c5..644a3b4 100644
> > --- a/include/uapi/linux/prctl.h
> > +++ b/include/uapi/linux/prctl.h
> > @@ -266,5 +266,8 @@ struct prctl_mm_map {
> > # define PR_SCHED_CORE_SHARE_TO 2 /* push core_sched cookie to pid */
> > # define PR_SCHED_CORE_SHARE_FROM 3 /* pull core_sched cookie to pid */
> > # define PR_SCHED_CORE_MAX 4
> > +# define PR_SCHED_CORE_SCOPE_THREAD 0
> > +# define PR_SCHED_CORE_SCOPE_THREAD_GROUP 1
> > +# define PR_SCHED_CORE_SCOPE_PROCESS_GROUP 2
> >
> > #endif /* _LINUX_PRCTL_H */
> > diff --git a/kernel/sched/core_sched.c b/kernel/sched/core_sched.c
> > index 9a80e9a..20f6409 100644
> > --- a/kernel/sched/core_sched.c
> > +++ b/kernel/sched/core_sched.c
> > @@ -134,6 +134,10 @@ int sched_core_share_pid(unsigned int cmd, pid_t pid, enum pid_type type,
> > if (!static_branch_likely(&sched_smt_present))
> > return -ENODEV;
> >
> > + BUILD_BUG_ON(PR_SCHED_CORE_SCOPE_THREAD != PIDTYPE_PID);
> > + BUILD_BUG_ON(PR_SCHED_CORE_SCOPE_THREAD_GROUP != PIDTYPE_TGID);
> > + BUILD_BUG_ON(PR_SCHED_CORE_SCOPE_PROCESS_GROUP != PIDTYPE_PGID);
> > +
> > if (type > PIDTYPE_PGID || cmd >= PR_SCHED_CORE_MAX || pid < 0 ||
> > (cmd != PR_SCHED_CORE_GET && uaddr))
> > return -EINVAL;
> > --
> > 2.1.4
> >
