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core/exec-invoke: use sched_setattr instead of sched_setscheduler

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The kernel's sched_setattr interface allows for more control over a processes
scheduling attributes as the previously used sched_setscheduler interface.

Using sched_setattr is also the prerequisite for support of utilization
clamping (UCLAMP [1], see #26705) and allows to set sched_runtime. The latter,
sched_runtime, will probably become a relevant scheduling parameter of the
EEVDF scheduler [2, 3], and therefore will not only apply to processes
scheduled via SCHED_DEADLINE, but also for processes scheduled via
SCHED_OTHER/SCHED_BATCH (i.e., most processes).

1: https://docs.kernel.org/next/scheduler/sched-util-clamp.html
2: https://lwn.net/Articles/969062/
3: https://lwn.net/ml/linux-kernel/20240405110010.934104715@infradead.org/
This commit is contained in:
Florian Schmaus
2024-06-26 20:54:53 +02:00
committed by Luca Boccassi
parent 0828c6a2bf
commit 016e9d8d08
4 changed files with 45 additions and 6 deletions
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src/core/exec-invoke.c
+7 -6
View File
@@ -1,5 +1,6 @@
/* SPDX-License-Identifier: LGPL-2.1-or-later */
#include <linux/sched.h>
#include <sys/eventfd.h>
#include <sys/ioctl.h>
#include <sys/mount.h>
@@ -44,6 +45,7 @@
#include "journal-send.h"
#include "missing_ioprio.h"
#include "missing_prctl.h"
#include "missing_sched.h"
#include "missing_securebits.h"
#include "missing_syscall.h"
#include "mkdir-label.h"
@@ -4411,15 +4413,14 @@ int exec_invoke(
}
if (context->cpu_sched_set) {
struct sched_param param = {
struct sched_attr attr = {
.size = sizeof(attr),
.sched_policy = context->cpu_sched_policy,
.sched_priority = context->cpu_sched_priority,
.sched_flags = context->cpu_sched_reset_on_fork ? SCHED_FLAG_RESET_ON_FORK : 0,
};
r = sched_setscheduler(0,
context->cpu_sched_policy |
(context->cpu_sched_reset_on_fork ?
SCHED_RESET_ON_FORK : 0),
&param);
r = sched_setattr(/* pid= */ 0, &attr, /* flags= */ 0);
if (r < 0) {
*exit_status = EXIT_SETSCHEDULER;
return log_exec_error_errno(context, params, errno, "Failed to set up CPU scheduling: %m");