Re: [libvirt] [PATCH 2/6] 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 | 70 +++++++++++++++++++++++++++++++++++++++++++++++-- src/util/virprocess.h | 28 +++++++++++++++++++- 3 files changed, 97 insertions(+), 4 deletions(-) diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c index 1b67aee..91a635c 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 d68800b..cd1cc9b 100644 --- a/src/util/virprocess.c +++ b/src/util/virprocess.c @@ -70,6 +70,7 @@ 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 @@ -91,9 +92,14 @@ VIR_LOG_INIT("util.process"); # endif # endif +# ifndef __NR_sched_setattr +# if defined(__x86_64__) +# define __NR_sched_setattr 314 +# endif +# endif +

# ifndef HAVE_SETNS # if defined(__NR_setns) -# include <sys/syscall.h> static inline int setns(int fd, int nstype) { @@ -103,6 +109,13 @@ static inline int setns(int fd, int nstype) # error Please determine the syscall number for setns on your architecture # endif # endif + +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 /* !__linux__ */ static inline int setns(int fd ATTRIBUTE_UNUSED, int nstype ATTRIBUTE_UNUSED) { @@ -110,6 +123,15 @@ static inline int setns(int fd ATTRIBUTE_UNUSED, int nstype ATTRIBUTE_UNUSED) _("Namespaces are not supported on this platform.")); return -1; } + +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 VIR_ENUM_IMPL(virProcessSchedPolicy, VIR_PROC_POLICY_LAST, @@ -1225,7 +1247,10 @@ 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}; int pol = virProcessSchedTranslatePolicy(policy); @@ -1235,6 +1260,47 @@ virProcessSetScheduler(pid_t pid, if (!policy) return 0; + if (pol == SCHED_DEADLINE) { + int ret = 0; + + if (runtime < 1024 || deadline < 1024 || period < 24) { + virReportError(VIR_ERR_CONFIG_UNSUPPORTED, + _("Scheduler runtime, deadline and period must be " + "higher or equal to 1024 (1 us) (runtime(%llu), " + "deadline(%llu), period(%llu))"), runtime, deadline, period); + return -1; + } + + if (!(runtime <= deadline && deadline <= period)) { + virReportError(VIR_ERR_CONFIG_UNSUPPORTED, + _("Scheduler configuration does not satisfy " + "(runtime(%llu) <= deadline(%llu) <= period(%llu))"), + runtime, deadline, period); + return -1; + } + + struct sched_attr attrs = { + .size = sizeof(attrs), + .sched_policy = SCHED_DEADLINE, + .sched_flags = 0, + .sched_nice = 0, + .sched_priority = 0, + .sched_runtime = runtime, + .sched_deadline = deadline, + .sched_period = period, + }; +

+ ret = sched_setattr(pid, &attrs, 0); + if (ret != 0) { + virReportSystemError(errno, + _("Cannot set scheduler parameters for pid %d"), + pid); + return -1; + } + + return 0; + } + if (pol == SCHED_FIFO || pol == SCHED_RR) { int min = 0; int max = 0; diff --git a/src/util/virprocess.h b/src/util/virprocess.h index 1eac3e6..e6914e7 100644 --- a/src/util/virprocess.h +++ b/src/util/virprocess.h @@ -23,6 +23,9 @@ # define __VIR_PROCESS_H__ # include <sys/types.h> +# ifdef __linux__ +# include <linux/types.h> +# endif # include "internal.h" # include "virbitmap.h" @@ -39,6 +42,26 @@ typedef enum { VIR_PROC_POLICY_LAST } virProcessSchedPolicy; +# ifdef __linux__ +struct sched_attr { + __u32 size; + + __u32 sched_policy; + __u64 sched_flags; + + /* SCHED_NORMAL, SCHED_BATCH */ + __s32 sched_nice; + + /* SCHED_FIFO, SCHED_RR */ + __u32 sched_priority; + + /* SCHED_DEADLINE (nsec) */ + __u64 sched_runtime; + __u64 sched_deadline; + __u64 sched_period; +}; +# endif +

VIR_ENUM_DECL(virProcessSchedPolicy); char * @@ -93,6 +116,9 @@ 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