3:01 a.m.
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