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

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/qemu/qemu_process.c b/src/qemu/qemu_process.c index 3552a31..e984ccd 100644 --- a/src/qemu/qemu_process.c +++ b/src/qemu/qemu_process.c @@ -2395,7 +2395,8 @@ qemuProcessSetupPid(virDomainObjPtr vm, /* Set scheduler type and priority. */ if (sched && - virProcessSetScheduler(pid, sched->policy, sched->priority) < 0) + virProcessSetScheduler(pid, sched->policy, sched->priority, + sched->runtime, sched->deadline, sched->period) < 0) goto cleanup; ret = 0; 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 @@ -67,6 +67,7 @@ VIR_LOG_INIT("util.process"); #ifdef __linux__ +# include <sys/syscall.h> /* * Workaround older glibc. While kernel may support the setns * syscall, the glibc wrapper might not exist. If that's the @@ -87,10 +88,8 @@ VIR_LOG_INIT("util.process"); # define __NR_setns 339 # endif # endif - # ifndef HAVE_SETNS # if defined(__NR_setns) -# include <sys/syscall.h> static inline int setns(int fd, int nstype) { @@ -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

#else /* !__linux__ */ static inline int setns(int fd ATTRIBUTE_UNUSED, int nstype ATTRIBUTE_UNUSED) { @@ -1234,10 +1251,16 @@ virProcessSchedTranslatePolicy(virProcessSchedPolicy policy) int virProcessSetScheduler(pid_t pid, virProcessSchedPolicy policy, - int priority) + int priority, + unsigned long long runtime, + unsigned long long deadline, + unsigned long long period) { struct sched_param param = {0}; + struct sched_attr attrs = { sizeof(attrs), SCHED_DEADLINE, 0, 0, 0, + runtime, deadline, period }; int pol = virProcessSchedTranslatePolicy(policy); + int ret = 0; VIR_DEBUG("pid=%lld, policy=%d, priority=%u", (long long) pid, policy, priority); @@ -1280,7 +1303,13 @@ virProcessSetScheduler(pid_t pid, param.sched_priority = priority; } - if (sched_setscheduler(pid, pol, &param) < 0) { + if (pol == SCHED_DEADLINE) { + ret = sched_setattr(pid, &attrs, 0); + } else { + ret = sched_setscheduler(pid, pol, &param); + } + + if (ret < 0) { virReportSystemError(errno, _("Cannot set scheduler parameters for pid %lld"), (long long) pid); diff --git a/src/util/virprocess.h b/src/util/virprocess.h index 1eac3e6..02522b4 100644 --- a/src/util/virprocess.h +++ b/src/util/virprocess.h @@ -41,6 +41,26 @@ typedef enum { VIR_ENUM_DECL(virProcessSchedPolicy); +# ifdef SCHED_DEADLINE +struct sched_attr { + uint32_t size; + + uint32_t sched_policy; + uint64_t sched_flags; + + /* SCHED_NORMAL, SCHED_BATCH */ + uint32_t sched_nice; + + /* SCHED_FIFO, SCHED_RR */ + uint32_t sched_priority; + + /* SCHED_DEADLINE (nsec) */ + uint64_t sched_runtime; + uint64_t sched_deadline; + uint64_t sched_period; +}; +# endif +

char * virProcessTranslateStatus(int status); @@ -93,6 +113,9 @@ int virProcessRunInMountNamespace(pid_t pid, int virProcessSetScheduler(pid_t pid, virProcessSchedPolicy policy, - int priority); + int priority, + unsigned long long runtime, + unsigned long long deadline, + unsigned long long period); #endif /* __VIR_PROCESS_H__ */ -- 2.8.1 -- libvir-list mailing list libvir-list(a)redhat.com https://www.redhat.com/mailman/listinfo/libvir-list