Re: [libvirt] [PATCH v2 2/5] util: allow virProcessSetScheduler to set SCHED_DEADLINE

On Mon, Nov 21, 2016 at 01:56:05PM +0100, Martin Polednik wrote: >As sched_deadline is linux specific, it is not set through >sched_setscheduler but rather the sched_setattr syscall. Additionally, >the scheduler has new set of parameters: runtime, deadline and period. > >In this part of the series, we extend virProcessSetScheduler to >accommodate the additional parameters and use sched_setattr syscall to >set SCHED_DEADLINE. Another small addition is sched_attr struct, which >is required for sched_setattr and not exposed from the kernel or >libraries. >--- > src/qemu/qemu_process.c | 3 ++- > src/util/virprocess.c | 37 +++++++++++++++++++++++++++++++++---- > src/util/virprocess.h | 25 ++++++++++++++++++++++++- > 3 files changed, 59 insertions(+), 6 deletions(-) > >diff --git a/src/util/virprocess.c b/src/util/virprocess.c >index 9b4a555..acf4d6b 100644 >--- a/src/util/virprocess.c >+++ b/src/util/virprocess.c >@@ -100,6 +99,24 @@ static inline int setns(int fd, int nstype) > # error Please determine the syscall number for setns on your architecture > # endif > # endif >+ >+# if defined(SCHED_DEADLINE) && defined(__NR_sched_setattr) >+static inline int sched_setattr(pid_t pid, >+ const struct sched_attr *attr, >+ unsigned int flags) >+{ >+ return syscall(__NR_sched_setattr, pid, attr, flags); >+} >+# else >+static inline int sched_setattr(pid_t pid, >+ const struct sched_attr *attr, >+ unsigned int flags) >+{ >+ virReportSystemError(ENOSYS, "%s", >+ _("Deadline scheduler is not supported on this platform.")); >+ return -1; >+} >+# endif As I said, no need to do that, just use AC_CHECK_FUNCS_ONCE we already have in configure.ac. Don't redefine it, just error out if it's not available.