iosched: break out io scheduling functions from xutils

Break this stuff out, for better maintainability and readability.

Signed-off-by: Daniel Borkmann <dborkman@redhat.com>

1 files changed, 76 insertions, 0 deletions

diff --git a/iosched.c b/iosched.c
new file mode 100644
index 0000000..7417973
--- /dev/null
+++ b/iosched.c
@@ -0,0 +1,76 @@
+/*
+ * netsniff-ng - the packet sniffing beast
+ * Copyright 2009, 2010 Daniel Borkmann.
+ * Copyright 2010 Marek Polacek.
+ * Subject to the GPL, version 2.
+ */
+
+#include <sys/syscall.h>
+
+#include "iosched.h"
+#include "die.h"
+
+#define IOPRIO_CLASS_SHIFT      13
+
+enum {
+	ioprio_class_none,
+	ioprio_class_rt,
+	ioprio_class_be,
+	ioprio_class_idle,
+};
+
+enum {
+	ioprio_who_process = 1,
+	ioprio_who_pgrp,
+	ioprio_who_user,
+};
+
+static const char *const to_prio[] = {
+	"none",
+	"realtime",
+	"best-effort",
+	"idle",
+};
+
+static inline int ioprio_set(int which, int who, int ioprio)
+{
+	return syscall(SYS_ioprio_set, which, who, ioprio);
+}
+
+static inline int ioprio_get(int which, int who)
+{
+	return syscall(SYS_ioprio_get, which, who);
+}
+
+static void ioprio_setpid(pid_t pid, int ioprio, int ioclass)
+{
+	int ret = ioprio_set(ioprio_who_process, pid,
+			     ioprio | ioclass << IOPRIO_CLASS_SHIFT);
+	if (ret < 0)
+		panic("Failed to set io prio for pid!\n");
+}
+
+void ioprio_print(void)
+{
+	int ioprio = ioprio_get(ioprio_who_process, getpid());
+	if (ioprio < 0)
+		panic("Failed to fetch io prio for pid!\n");
+	else {
+		int ioclass = ioprio >> IOPRIO_CLASS_SHIFT;
+		if (ioclass != ioprio_class_idle) {
+			ioprio &= 0xff;
+			printf("%s: prio %d\n", to_prio[ioclass], ioprio);
+		} else
+			printf("%s\n", to_prio[ioclass]);
+	}
+}
+
+void set_ioprio_rt(void)
+{
+	ioprio_setpid(getpid(), 4, ioprio_class_rt);
+}
+
+void set_ioprio_be(void)
+{
+	ioprio_setpid(getpid(), 4, ioprio_class_be);
+}