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/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
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.
#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, ¶m) < 0) {
+ if (pol == SCHED_DEADLINE) {
+ ret = sched_setattr(pid, &attrs, 0);
+ } else {
+ ret = sched_setscheduler(pid, pol, ¶m);
+ }
+
+ 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
+
There's no need to expose this in a header file, move it to virprocess.c.
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
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