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authorPeter Zijlstra <a.p.zijlstra@chello.nl>2008-04-30 03:54:32 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2008-04-30 11:29:49 -0400
commitcf0ca9fe5dd9e3693d935757a7b2fc50fc576554 (patch)
treec795c5271eda9fc67579fa3176c646b892dfdb41 /mm
parentcaafa4324335aeb11bc233d5f87aca8cce30beba (diff)
mm: bdi: export BDI attributes in sysfs
Provide a place in sysfs (/sys/class/bdi) for the backing_dev_info object. This allows us to see and set the various BDI specific variables. In particular this properly exposes the read-ahead window for all relevant users and /sys/block/<block>/queue/read_ahead_kb should be deprecated. With patient help from Kay Sievers and Greg KH [mszeredi@suse.cz] - split off NFS and FUSE changes into separate patches - document new sysfs attributes under Documentation/ABI - do bdi_class_init as a core_initcall, otherwise the "default" BDI won't be initialized - remove bdi_init_fmt macro, it's not used very much [akpm@linux-foundation.org: fix ia64 warning] Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Kay Sievers <kay.sievers@vrfy.org> Acked-by: Greg KH <greg@kroah.com> Cc: Trond Myklebust <trond.myklebust@fys.uio.no> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/backing-dev.c119
-rw-r--r--mm/page-writeback.c2
-rw-r--r--mm/readahead.c8
3 files changed, 127 insertions, 2 deletions
diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index e8644b1e5527..847eabe4824c 100644
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -4,12 +4,129 @@
4#include <linux/fs.h> 4#include <linux/fs.h>
5#include <linux/sched.h> 5#include <linux/sched.h>
6#include <linux/module.h> 6#include <linux/module.h>
7#include <linux/writeback.h>
8#include <linux/device.h>
9
10
11static struct class *bdi_class;
12
13static ssize_t read_ahead_kb_store(struct device *dev,
14 struct device_attribute *attr,
15 const char *buf, size_t count)
16{
17 struct backing_dev_info *bdi = dev_get_drvdata(dev);
18 char *end;
19 unsigned long read_ahead_kb;
20 ssize_t ret = -EINVAL;
21
22 read_ahead_kb = simple_strtoul(buf, &end, 10);
23 if (*buf && (end[0] == '\0' || (end[0] == '\n' && end[1] == '\0'))) {
24 bdi->ra_pages = read_ahead_kb >> (PAGE_SHIFT - 10);
25 ret = count;
26 }
27 return ret;
28}
29
30#define K(pages) ((pages) << (PAGE_SHIFT - 10))
31
32#define BDI_SHOW(name, expr) \
33static ssize_t name##_show(struct device *dev, \
34 struct device_attribute *attr, char *page) \
35{ \
36 struct backing_dev_info *bdi = dev_get_drvdata(dev); \
37 \
38 return snprintf(page, PAGE_SIZE-1, "%lld\n", (long long)expr); \
39}
40
41BDI_SHOW(read_ahead_kb, K(bdi->ra_pages))
42
43BDI_SHOW(reclaimable_kb, K(bdi_stat(bdi, BDI_RECLAIMABLE)))
44BDI_SHOW(writeback_kb, K(bdi_stat(bdi, BDI_WRITEBACK)))
45
46static inline unsigned long get_dirty(struct backing_dev_info *bdi, int i)
47{
48 unsigned long thresh[3];
49
50 get_dirty_limits(&thresh[0], &thresh[1], &thresh[2], bdi);
51
52 return thresh[i];
53}
54
55BDI_SHOW(dirty_kb, K(get_dirty(bdi, 1)))
56BDI_SHOW(bdi_dirty_kb, K(get_dirty(bdi, 2)))
57
58#define __ATTR_RW(attr) __ATTR(attr, 0644, attr##_show, attr##_store)
59
60static struct device_attribute bdi_dev_attrs[] = {
61 __ATTR_RW(read_ahead_kb),
62 __ATTR_RO(reclaimable_kb),
63 __ATTR_RO(writeback_kb),
64 __ATTR_RO(dirty_kb),
65 __ATTR_RO(bdi_dirty_kb),
66 __ATTR_NULL,
67};
68
69static __init int bdi_class_init(void)
70{
71 bdi_class = class_create(THIS_MODULE, "bdi");
72 bdi_class->dev_attrs = bdi_dev_attrs;
73 return 0;
74}
75
76core_initcall(bdi_class_init);
77
78int bdi_register(struct backing_dev_info *bdi, struct device *parent,
79 const char *fmt, ...)
80{
81 char *name;
82 va_list args;
83 int ret = 0;
84 struct device *dev;
85
86 va_start(args, fmt);
87 name = kvasprintf(GFP_KERNEL, fmt, args);
88 va_end(args);
89
90 if (!name)
91 return -ENOMEM;
92
93 dev = device_create(bdi_class, parent, MKDEV(0, 0), name);
94 if (IS_ERR(dev)) {
95 ret = PTR_ERR(dev);
96 goto exit;
97 }
98
99 bdi->dev = dev;
100 dev_set_drvdata(bdi->dev, bdi);
101
102exit:
103 kfree(name);
104 return ret;
105}
106EXPORT_SYMBOL(bdi_register);
107
108int bdi_register_dev(struct backing_dev_info *bdi, dev_t dev)
109{
110 return bdi_register(bdi, NULL, "%u:%u", MAJOR(dev), MINOR(dev));
111}
112EXPORT_SYMBOL(bdi_register_dev);
113
114void bdi_unregister(struct backing_dev_info *bdi)
115{
116 if (bdi->dev) {
117 device_unregister(bdi->dev);
118 bdi->dev = NULL;
119 }
120}
121EXPORT_SYMBOL(bdi_unregister);
7 122
8int bdi_init(struct backing_dev_info *bdi) 123int bdi_init(struct backing_dev_info *bdi)
9{ 124{
10 int i; 125 int i;
11 int err; 126 int err;
12 127
128 bdi->dev = NULL;
129
13 for (i = 0; i < NR_BDI_STAT_ITEMS; i++) { 130 for (i = 0; i < NR_BDI_STAT_ITEMS; i++) {
14 err = percpu_counter_init_irq(&bdi->bdi_stat[i], 0); 131 err = percpu_counter_init_irq(&bdi->bdi_stat[i], 0);
15 if (err) 132 if (err)
@@ -33,6 +150,8 @@ void bdi_destroy(struct backing_dev_info *bdi)
33{ 150{
34 int i; 151 int i;
35 152
153 bdi_unregister(bdi);
154
36 for (i = 0; i < NR_BDI_STAT_ITEMS; i++) 155 for (i = 0; i < NR_BDI_STAT_ITEMS; i++)
37 percpu_counter_destroy(&bdi->bdi_stat[i]); 156 percpu_counter_destroy(&bdi->bdi_stat[i]);
38 157
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 5e00f1772c20..e5b6b1190a95 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -300,7 +300,7 @@ static unsigned long determine_dirtyable_memory(void)
300 return x + 1; /* Ensure that we never return 0 */ 300 return x + 1; /* Ensure that we never return 0 */
301} 301}
302 302
303static void 303void
304get_dirty_limits(long *pbackground, long *pdirty, long *pbdi_dirty, 304get_dirty_limits(long *pbackground, long *pdirty, long *pbdi_dirty,
305 struct backing_dev_info *bdi) 305 struct backing_dev_info *bdi)
306{ 306{
diff --git a/mm/readahead.c b/mm/readahead.c
index 8762e8988972..d8723a5f6496 100644
--- a/mm/readahead.c
+++ b/mm/readahead.c
@@ -235,7 +235,13 @@ unsigned long max_sane_readahead(unsigned long nr)
235 235
236static int __init readahead_init(void) 236static int __init readahead_init(void)
237{ 237{
238 return bdi_init(&default_backing_dev_info); 238 int err;
239
240 err = bdi_init(&default_backing_dev_info);
241 if (!err)
242 bdi_register(&default_backing_dev_info, NULL, "default");
243
244 return err;
239} 245}
240subsys_initcall(readahead_init); 246subsys_initcall(readahead_init);
241 247