summaryrefslogtreecommitdiff
path: root/iosched.c
blob: ff82126831210ff83bb118f84396adefe417f26b (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
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: %s\n", strerror(errno));
}

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);
}
ch_to+0x2c0/0x450 __schedule+0x2f8/0x970 schedule+0x48/0xc0 blk_mq_freeze_queue_wait+0x94/0x120 blk_mq_queue_reinit_work+0xb8/0x180 blk_mq_queue_reinit_prepare+0x84/0xa0 cpuhp_invoke_callback+0x17c/0x600 cpuhp_up_callbacks+0x58/0x150 _cpu_up+0xf0/0x1c0 do_cpu_up+0x120/0x150 cpu_subsys_online+0x64/0xe0 device_online+0xb4/0x120 online_store+0xb4/0xc0 dev_attr_store+0x68/0xa0 sysfs_kf_write+0x80/0xb0 kernfs_fop_write+0x17c/0x250 __vfs_write+0x6c/0x1e0 vfs_write+0xd0/0x270 SyS_write+0x6c/0x110 system_call+0x38/0xe0 Examination of the queue showed a single reference (no PERCPU_COUNT_BIAS, and __PERCPU_REF_DEAD, __PERCPU_REF_ATOMIC set) and no requests. However, conditions at the time of the race are count of PERCPU_COUNT_BIAS + 0 and __PERCPU_REF_DEAD and __PERCPU_REF_ATOMIC set. The fix is to make the tryget routines use an actual boolean internally instead of the atomic long result truncated to a int. Fixes: e625305b3907 percpu-refcount: make percpu_ref based on longs instead of ints Link: https://bugzilla.kernel.org/show_bug.cgi?id=190751 Signed-off-by: Douglas Miller <dougmill@linux.vnet.ibm.com> Reviewed-by: Jens Axboe <axboe@fb.com> Signed-off-by: Tejun Heo <tj@kernel.org> Fixes: e625305b3907 ("percpu-refcount: make percpu_ref based on longs instead of ints") Cc: stable@vger.kernel.org # v3.18+
Diffstat (limited to 'include/math-emu/op-2.h')