Adding upstream version 43.5.upstream/43.5upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 197 insertions, 0 deletions

diff --git a/lib/gs-ioprio.c b/lib/gs-ioprio.c
new file mode 100644
index 0000000..3a63d07
--- /dev/null
+++ b/lib/gs-ioprio.c
@@ -0,0 +1,197 @@
+/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*-
+ * vi:set noexpandtab tabstop=8 shiftwidth=8:
+ *
+ * Copyright (C) 2005, Novell, Inc.
+ * Copyright (C) 2006, Jamie McCracken <jamiemcc@gnome.org>
+ * Copyright (C) 2006, Anders Aagaard
+ *
+ * Based mostly on code by Robert Love <rml@novell.com>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+
+#include "config.h"
+
+#ifdef __linux__
+
+#include <stdio.h>
+#include <errno.h>
+
+#ifdef HAVE_LINUX_UNISTD_H
+#include <linux/unistd.h>
+#endif
+
+#include <sys/syscall.h>
+#include <unistd.h>
+
+#include <glib/gstdio.h>
+
+#endif /* __linux__ */
+
+#include "gs-ioprio.h"
+
+/* We assume ALL linux architectures have the syscalls defined here */
+#ifdef __linux__
+
+/* Make sure the system call is supported */
+#ifndef __NR_ioprio_set
+
+#if defined(__i386__)
+#define __NR_ioprio_set                 289
+#define __NR_ioprio_get                 290
+#elif defined(__powerpc__) || defined(__powerpc64__)
+#define __NR_ioprio_set                 273
+#define __NR_ioprio_get                 274
+#elif defined(__x86_64__)
+#define __NR_ioprio_set                 251
+#define __NR_ioprio_get                 252
+#elif defined(__ia64__)
+#define __NR_ioprio_set                 1274
+#define __NR_ioprio_get                 1275
+#elif defined(__alpha__)
+#define __NR_ioprio_set                 442
+#define __NR_ioprio_get                 443
+#elif defined(__s390x__) || defined(__s390__)
+#define __NR_ioprio_set                 282
+#define __NR_ioprio_get                 283
+#elif defined(__SH4__)
+#define __NR_ioprio_set                 288
+#define __NR_ioprio_get                 289
+#elif defined(__SH5__)
+#define __NR_ioprio_set                 316
+#define __NR_ioprio_get                 317
+#elif defined(__sparc__) || defined(__sparc64__)
+#define __NR_ioprio_set                 196
+#define __NR_ioprio_get                 218
+#elif defined(__arm__)
+#define __NR_ioprio_set                 314
+#define __NR_ioprio_get                 315
+#else
+#error "Unsupported architecture!"
+#endif
+
+#endif /* __NR_ioprio_set */
+
+enum {
+	IOPRIO_CLASS_NONE,
+	IOPRIO_CLASS_RT,
+	IOPRIO_CLASS_BE,
+	IOPRIO_CLASS_IDLE,
+};
+
+enum {
+	IOPRIO_WHO_PROCESS = 1,
+	IOPRIO_WHO_PGRP,
+	IOPRIO_WHO_USER,
+};
+
+#define IOPRIO_CLASS_SHIFT 13
+
+static inline int
+ioprio_set (int which, int who, int ioprio_val)
+{
+	return syscall (__NR_ioprio_set, which, who, ioprio_val);
+}
+
+static int
+set_io_priority (int ioprio,
+		 int ioclass)
+{
+	return ioprio_set (IOPRIO_WHO_PROCESS, 0, ioprio | (ioclass << IOPRIO_CLASS_SHIFT));
+}
+
+static const gchar *
+ioclass_to_string (int ioclass)
+{
+	switch (ioclass) {
+	case IOPRIO_CLASS_IDLE:
+		return "IDLE";
+	case IOPRIO_CLASS_BE:
+		return "BE";
+	default:
+		return "unknown";
+	}
+}
+
+/**
+ * gs_ioprio_set:
+ * @priority: I/O priority, with higher numeric values indicating lower priority;
+ *   use %G_PRIORITY_DEFAULT as the default
+ *
+ * Set the I/O priority of the current thread using the `ioprio_set()` syscall.
+ *
+ * The @priority is quantised before being passed to the kernel.
+ *
+ * This function may fail if the process doesn’t have permission to change its
+ * I/O priority to the given value. If so, a warning will be printed, as the
+ * quantised priority values are chosen so they shouldn’t typically require
+ * permissions to set.
+ */
+void
+gs_ioprio_set (gint priority)
+{
+	int ioprio, ioclass;
+
+	/* If the priority is lower than default, use an idle I/O priority. The
+	 * condition looks wrong because higher integers indicate lower priority
+	 * in GLib.
+	 *
+	 * Otherwise use a default best-effort priority, which is the same as
+	 * what all new threads get (in the absence of an I/O context with
+	 * `CLONE_IO`). */
+	if (priority > G_PRIORITY_DEFAULT) {
+		ioprio = 7;
+		ioclass = IOPRIO_CLASS_IDLE;
+	} else if (priority == G_PRIORITY_DEFAULT) {
+		ioprio = 4;  /* this is the default priority in the BE class */
+		ioclass = IOPRIO_CLASS_BE;
+	} else {
+		ioprio = 0;  /* this is the highest priority in the BE class */
+		ioclass = IOPRIO_CLASS_BE;
+	}
+
+	g_debug ("Setting I/O priority of thread %p to %s, %d",
+		 g_thread_self (), ioclass_to_string (ioclass), ioprio);
+
+	if (set_io_priority (ioprio, ioclass) == -1) {
+		g_warning ("Could not set I/O priority to %s, %d",
+			   ioclass_to_string (ioclass), ioprio);
+
+		/* If we were trying to set to idle priority, try again with the
+		 * lowest-possible best-effort priority. This is because kernels
+		 * older than 2.6.25 required `CAP_SYS_ADMIN` to set
+		 * `IOPRIO_CLASS_IDLE`. Newer kernels do not. */
+		if (ioclass == IOPRIO_CLASS_IDLE) {
+			ioprio = 7;  /* this is the lowest priority in the BE class */
+			ioclass = IOPRIO_CLASS_BE;
+
+			if (set_io_priority (ioprio, ioclass) == -1)
+				g_warning ("Could not set best effort IO priority either, giving up");
+		}
+	}
+}
+
+#else  /* __linux__ */
+
+void
+gs_ioprio_set (gint priority)
+{
+}
+
+#endif /* __linux__ */