---

yaml
---
r: 3617
b: refs/heads/master
c: 8b789b7
h: refs/heads/master
i:
  3615: 5e3308a
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: b46ffaefe3c251897de23e5a534dd922c969d67b
+refs/heads/master: 8b789b7d7e9b12b086d6d2f0759073a11447c7e7

trunk/Documentation/block/ioprio.txt

@@ -0,0 +1,176 @@
+Block io priorities
+===================
+
+
+Intro
+-----
+
+With the introduction of cfq v3 (aka cfq-ts or time sliced cfq), basic io
+priorities is supported for reads on files. This enables users to io nice
+processes or process groups, similar to what has been possible to cpu
+scheduling for ages. This document mainly details the current possibilites
+with cfq, other io schedulers do not support io priorities so far.
+
+Scheduling classes
+------------------
+
+CFQ implements three generic scheduling classes that determine how io is
+served for a process.
+
+IOPRIO_CLASS_RT: This is the realtime io class. This scheduling class is given
+higher priority than any other in the system, processes from this class are
+given first access to the disk every time. Thus it needs to be used with some
+care, one io RT process can starve the entire system. Within the RT class,
+there are 8 levels of class data that determine exactly how much time this
+process needs the disk for on each service. In the future this might change
+to be more directly mappable to performance, by passing in a wanted data
+rate instead.
+
+IOPRIO_CLASS_BE: This is the best-effort scheduling class, which is the default
+for any process that hasn't set a specific io priority. The class data
+determines how much io bandwidth the process will get, it's directly mappable
+to the cpu nice levels just more coarsely implemented. 0 is the highest
+BE prio level, 7 is the lowest. The mapping between cpu nice level and io
+nice level is determined as: io_nice = (cpu_nice + 20) / 5.
+
+IOPRIO_CLASS_IDLE: This is the idle scheduling class, processes running at this
+level only get io time when no one else needs the disk. The idle class has no
+class data, since it doesn't really apply here.
+
+Tools
+-----
+
+See below for a sample ionice tool. Usage:
+
+# ionice -c<class> -n<level> -p<pid>
+
+If pid isn't given, the current process is assumed. IO priority settings
+are inherited on fork, so you can use ionice to start the process at a given
+level:
+
+# ionice -c2 -n0 /bin/ls
+
+will run ls at the best-effort scheduling class at the highest priority.
+For a running process, you can give the pid instead:
+
+# ionice -c1 -n2 -p100
+
+will change pid 100 to run at the realtime scheduling class, at priority 2.
+
+---> snip ionice.c tool <---
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <getopt.h>
+#include <unistd.h>
+#include <sys/ptrace.h>
+#include <asm/unistd.h>
+
+extern int sys_ioprio_set(int, int, int);
+extern int sys_ioprio_get(int, int);
+
+#if defined(__i386__)
+#define __NR_ioprio_set		289
+#define __NR_ioprio_get		290
+#elif defined(__ppc__)
+#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
+#else
+#error "Unsupported arch"
+#endif
+
+_syscall3(int, ioprio_set, int, which, int, who, int, ioprio);
+_syscall2(int, ioprio_get, int, which, int, who);
+
+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
+
+const char *to_prio[] = { "none", "realtime", "best-effort", "idle", };
+
+int main(int argc, char *argv[])
+{
+	int ioprio = 4, set = 0, ioprio_class = IOPRIO_CLASS_BE;
+	int c, pid = 0;
+
+	while ((c = getopt(argc, argv, "+n:c:p:")) != EOF) {
+		switch (c) {
+		case 'n':
+			ioprio = strtol(optarg, NULL, 10);
+			set = 1;
+			break;
+		case 'c':
+			ioprio_class = strtol(optarg, NULL, 10);
+			set = 1;
+			break;
+		case 'p':
+			pid = strtol(optarg, NULL, 10);
+			break;
+		}
+	}
+
+	switch (ioprio_class) {
+		case IOPRIO_CLASS_NONE:
+			ioprio_class = IOPRIO_CLASS_BE;
+			break;
+		case IOPRIO_CLASS_RT:
+		case IOPRIO_CLASS_BE:
+			break;
+		case IOPRIO_CLASS_IDLE:
+			ioprio = 7;
+			break;
+		default:
+			printf("bad prio class %d\n", ioprio_class);
+			return 1;
+	}
+
+	if (!set) {
+		if (!pid && argv[optind])
+			pid = strtol(argv[optind], NULL, 10);
+
+		ioprio = ioprio_get(IOPRIO_WHO_PROCESS, pid);
+
+		printf("pid=%d, %d\n", pid, ioprio);
+
+		if (ioprio == -1)
+			perror("ioprio_get");
+		else {
+			ioprio_class = ioprio >> IOPRIO_CLASS_SHIFT;
+			ioprio = ioprio & 0xff;
+			printf("%s: prio %d\n", to_prio[ioprio_class], ioprio);
+		}
+	} else {
+		if (ioprio_set(IOPRIO_WHO_PROCESS, pid, ioprio | ioprio_class << IOPRIO_CLASS_SHIFT) == -1) {
+			perror("ioprio_set");
+			return 1;
+		}
+
+		if (argv[optind])
+			execvp(argv[optind], &argv[optind]);
+	}
+
+	return 0;
+}
+
+---> snip ionice.c tool <---
+
+
+March 11 2005, Jens Axboe <axboe@suse.de>

trunk/Documentation/kernel-parameters.txt

@@ -1115,7 +1115,7 @@ running once the system is up.
 			See Documentation/ramdisk.txt.
 
 	psmouse.proto=  [HW,MOUSE] Highest PS2 mouse protocol extension to
-			probe for (bare|imps|exps).
+			probe for (bare|imps|exps|lifebook|any).
 	psmouse.rate=	[HW,MOUSE] Set desired mouse report rate, in reports
 			per second.
 	psmouse.resetafter=

trunk/arch/i386/kernel/syscall_table.S

@@ -289,3 +289,5 @@ ENTRY(sys_call_table)
 	.long sys_add_key
 	.long sys_request_key
 	.long sys_keyctl
+	.long sys_ioprio_set
+	.long sys_ioprio_get		/* 290 */

trunk/arch/ia64/kernel/entry.S

@@ -1577,8 +1577,8 @@ sys_call_table:
 	data8 sys_add_key
 	data8 sys_request_key
 	data8 sys_keyctl
-	data8 sys_ni_syscall
-	data8 sys_ni_syscall			// 1275
+	data8 sys_ioprio_set
+	data8 sys_ioprio_get			// 1275
 	data8 sys_set_zone_reclaim
 	data8 sys_ni_syscall
 	data8 sys_ni_syscall

trunk/arch/ppc/kernel/misc.S

@@ -1449,3 +1449,5 @@ _GLOBAL(sys_call_table)
 	.long sys_request_key		/* 270 */
 	.long sys_keyctl
 	.long sys_waitid
+	.long sys_ioprio_set
+	.long sys_ioprio_get

trunk/drivers/block/as-iosched.c

@@ -1806,7 +1806,8 @@ static void as_put_request(request_queue_t *q, struct request *rq)
 	rq->elevator_private = NULL;
 }
 
-static int as_set_request(request_queue_t *q, struct request *rq, int gfp_mask)
+static int as_set_request(request_queue_t *q, struct request *rq,
+			  struct bio *bio, int gfp_mask)
 {
 	struct as_data *ad = q->elevator->elevator_data;
 	struct as_rq *arq = mempool_alloc(ad->arq_pool, gfp_mask);
@@ -1827,7 +1828,7 @@ static int as_set_request(request_queue_t *q, struct request *rq, int gfp_mask)
 	return 1;
 }
 
-static int as_may_queue(request_queue_t *q, int rw)
+static int as_may_queue(request_queue_t *q, int rw, struct bio *bio)
 {
 	int ret = ELV_MQUEUE_MAY;
 	struct as_data *ad = q->elevator->elevator_data;