summaryrefslogtreecommitdiffstats
path: root/src/basic/ioprio.h
diff options
context:
space:
mode:
authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-27 13:00:47 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-27 13:00:47 +0000
commit2cb7e0aaedad73b076ea18c6900b0e86c5760d79 (patch)
treeda68ca54bb79f4080079bf0828acda937593a4e1 /src/basic/ioprio.h
parentInitial commit. (diff)
downloadsystemd-2cb7e0aaedad73b076ea18c6900b0e86c5760d79.tar.xz
systemd-2cb7e0aaedad73b076ea18c6900b0e86c5760d79.zip
Adding upstream version 247.3.upstream/247.3upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/basic/ioprio.h')
-rw-r--r--src/basic/ioprio.h56
1 files changed, 56 insertions, 0 deletions
diff --git a/src/basic/ioprio.h b/src/basic/ioprio.h
new file mode 100644
index 0000000..3fb168d
--- /dev/null
+++ b/src/basic/ioprio.h
@@ -0,0 +1,56 @@
+#ifndef IOPRIO_H
+#define IOPRIO_H
+
+/* This is minimal version of Linux' linux/ioprio.h header file, which
+ * is licensed GPL2 */
+
+#include <sys/syscall.h>
+#include <unistd.h>
+
+/*
+ * Gives us 8 prio classes with 13-bits of data for each class
+ */
+#define IOPRIO_BITS 16
+#define IOPRIO_N_CLASSES 8
+#define IOPRIO_CLASS_SHIFT 13
+#define IOPRIO_PRIO_MASK ((1UL << IOPRIO_CLASS_SHIFT) - 1)
+
+#define IOPRIO_PRIO_CLASS(mask) ((mask) >> IOPRIO_CLASS_SHIFT)
+#define IOPRIO_PRIO_DATA(mask) ((mask) & IOPRIO_PRIO_MASK)
+#define IOPRIO_PRIO_VALUE(class, data) (((class) << IOPRIO_CLASS_SHIFT) | data)
+
+#define ioprio_valid(mask) (IOPRIO_PRIO_CLASS((mask)) != IOPRIO_CLASS_NONE)
+
+/*
+ * These are the io priority groups as implemented by CFQ. RT is the realtime
+ * class, it always gets premium service. BE is the best-effort scheduling
+ * class, the default for any process. IDLE is the idle scheduling class, it
+ * is only served when no one else is using the disk.
+ */
+enum {
+ IOPRIO_CLASS_NONE,
+ IOPRIO_CLASS_RT,
+ IOPRIO_CLASS_BE,
+ IOPRIO_CLASS_IDLE,
+};
+
+/*
+ * 8 best effort priority levels are supported
+ */
+#define IOPRIO_BE_NR (8)
+
+enum {
+ IOPRIO_WHO_PROCESS = 1,
+ IOPRIO_WHO_PGRP,
+ IOPRIO_WHO_USER,
+};
+
+static inline int ioprio_set(int which, int who, int ioprio) {
+ return syscall(__NR_ioprio_set, which, who, ioprio);
+}
+
+static inline int ioprio_get(int which, int who) {
+ return syscall(__NR_ioprio_get, which, who);
+}
+
+#endif