Add support for scheduling policies

Add a process column for scheduling policy to show the current
scheduling policy of the process.

Add a the ability to change the scheduling policy of a process via the
key 'Y'.

Currently implemented on Linux and FreeBSD only but should be portable,
since sched_getscheduler(2) is part of POSIX.1-2001.

Closes: #1161

1 files changed, 49 insertions, 0 deletions

diff --git a/Scheduling.h b/Scheduling.h
new file mode 100644
index 00000000..d91855ae
--- /dev/null
+++ b/Scheduling.h
@@ -0,0 +1,49 @@
+#ifndef HEADER_Scheduling
+#define HEADER_Scheduling
+/*
+htop - Scheduling.h
+(C) 2023 htop dev team
+Released under the GNU GPLv2+, see the COPYING file
+in the source distribution for its full text.
+*/
+
+#include "config.h" // IWYU pragma: keep
+
+#include <sched.h>
+#include <stdbool.h>
+
+#include "Panel.h"
+
+
+#if defined(HAVE_SCHED_SETSCHEDULER) && defined(HAVE_SCHED_GETSCHEDULER)
+#define SCHEDULER_SUPPORT
+
+typedef struct {
+   const char* name;
+   int id;
+   bool prioritySupport;
+} SchedulingPolicy;
+
+#define SCHEDULINGPANEL_INITSELECTEDPOLICY SCHED_OTHER
+#define SCHEDULINGPANEL_INITSELECTEDPRIORITY 50
+
+Panel* Scheduling_newPolicyPanel(int preSelectedPolicy);
+void Scheduling_togglePolicyPanelResetOnFork(Panel* schedPanel);
+
+Panel* Scheduling_newPriorityPanel(int policy, int preSelectedPriority);
+
+
+typedef struct {
+   int policy;
+   int priority;
+} SchedulingArg;
+
+bool Scheduling_setPolicy(Process* proc, Arg arg);
+
+const char* Scheduling_formatPolicy(int policy);
+
+void Scheduling_readProcessPolicy(Process* proc);
+
+#endif
+
+#endif  /* HEADER_Scheduling */