From 3bf68910c3425dc4563ba74c671a9b0e311873e2 Mon Sep 17 00:00:00 2001
From: Karel Zak <kzak@redhat.com>
Date: Mon, 3 Oct 2016 11:02:35 +0200
Subject: [PATCH 199/201] chrt: follow nice setting, prefer
sched_setscheduler()
* do not reset 'nice' setting by sched_setattr(), if 'nice' setting
is not zero then chrt ends with EPERM for non-root users:
$ renice -n 5 -p $$; chrt -v -b 0 date
12475 (process ID) old priority 0, new priority 5
chrt: failed to set pid 0's policy: Operation not permitted
* it seems more elegant to always use old sched_setscheduler() API for
non-deadline policies; in this case we do not need getpriority()
to keep 'nice' unchanged.
Addresses: https://github.com/karelzak/util-linux/issues/359
Addresses: https://bugzilla.redhat.com/show_bug.cgi?id=1905956
Signed-off-by: Karel Zak <kzak@redhat.com>
---
schedutils/chrt.c | 34 ++++++++++++++++++----------------
1 file changed, 18 insertions(+), 16 deletions(-)
diff --git a/schedutils/chrt.c b/schedutils/chrt.c
index edae0d9f4..0a51c1088 100644
--- a/schedutils/chrt.c
+++ b/schedutils/chrt.c
@@ -26,6 +26,8 @@
#include <unistd.h>
#include <getopt.h>
#include <errno.h>
+#include <sys/time.h>
+#include <sys/resource.h>
#include "c.h"
#include "nls.h"
@@ -340,6 +342,7 @@ static int set_sched_one_by_setscheduler(struct chrt_ctl *ctl, pid_t pid)
struct sched_param sp = { .sched_priority = ctl->priority };
int policy = ctl->policy;
+ errno = 0;
# ifdef SCHED_RESET_ON_FORK
if (ctl->reset_on_fork)
policy |= SCHED_RESET_ON_FORK;
@@ -357,29 +360,28 @@ static int set_sched_one(struct chrt_ctl *ctl, pid_t pid)
#else /* !HAVE_SCHED_SETATTR */
static int set_sched_one(struct chrt_ctl *ctl, pid_t pid)
{
+ struct sched_attr sa = { .size = sizeof(struct sched_attr) };
+
+ /* old API is good enough for non-deadline */
+ if (ctl->policy != SCHED_DEADLINE)
+ return set_sched_one_by_setscheduler(ctl, pid);
+
+ /* no changeed by chrt, follow the current setting */
+ sa.sched_nice = getpriority(PRIO_PROCESS, pid);
+
/* use main() to check if the setting makes sense */
- struct sched_attr sa = {
- .size = sizeof(struct sched_attr),
- .sched_policy = ctl->policy,
- .sched_priority = ctl->priority,
- .sched_runtime = ctl->runtime,
- .sched_period = ctl->period,
- .sched_deadline = ctl->deadline
- };
- int rc;
+ sa.sched_policy = ctl->policy;
+ sa.sched_priority = ctl->priority;
+ sa.sched_runtime = ctl->runtime;
+ sa.sched_period = ctl->period;
+ sa.sched_deadline = ctl->deadline;
# ifdef SCHED_RESET_ON_FORK
if (ctl->reset_on_fork)
sa.sched_flags |= SCHED_RESET_ON_FORK;
# endif
errno = 0;
- rc = sched_setattr(pid, &sa, 0);
-
- if (rc != 0 && errno == ENOSYS && ctl->policy != SCHED_DEADLINE)
- /* fallback -- build with new kernel/libc, but executed on old kernels */
- rc = set_sched_one_by_setscheduler(ctl, pid);
-
- return rc;
+ return sched_setattr(pid, &sa, 0);
}
#endif /* HAVE_SCHED_SETATTR */
--
2.28.0