On Fri, 2007-10-26 at 19:40 -0700, Greg KH wrote:
> On Sat, Oct 27, 2007 at 03:18:08AM +0200, Peter Zijlstra wrote:
> >
> > On Fri, 2007-10-26 at 22:04 +0200, Peter Zijlstra wrote:
> > > This crashes and burns on bootup, but I'm too tired to figure out what I
> > > did wrong... will give it another try tomorrow..
> >
> > Ok, can't sleep.. took a look. I have several problems here.
> >
> > The thing that makes it go *boom* is the __ATTR_NULL. Removing that
> > makes it boot. Albeit it then warns me of multiple duplicate sysfs
> > objects, all named "bdi".
> >
> > For some obscure reason this device interface insists on using the
> > bus_id as name (?!), and further reduces usability by limiting that to
> > 20 odd characters.
> >
> > This makes it quite useless. I tried fudging around that limit by using
> > device_rename and kobject_rename, but to no avail.
> >
> > Really, it should not be this hard to use, trying to expose a handfull
> > of simple integers to userspace should not take 8h+ and still not work.
> >
> > Peter, who thinks sysfs is contorted mess beyond his skill. I'll stick
> > to VM and scheduler code, that actually makes sense.
>
> Heh, that's funny :)
>
> I'll look at this and see what I can come up with. Would you just like
> a whole new patch, or one against this one?
Sorry for the grumpy note, I get that way at 3.30 am. Maybe I ought not
have mailed :-/
This is the code I had at that time.
Signed-off-by: Peter Zijlstra <[email protected]>
---
block/genhd.c | 2
fs/fuse/inode.c | 2
fs/nfs/client.c | 2
include/linux/backing-dev.h | 21 ++++++
include/linux/string.h | 4 +
include/linux/writeback.h | 3
mm/backing-dev.c | 144 ++++++++++++++++++++++++++++++++++++++++++++
mm/page-writeback.c | 2
mm/util.c | 42 ++++++++++++
9 files changed, 219 insertions(+), 3 deletions(-)
Index: linux-2.6-2/fs/fuse/inode.c
===================================================================
--- linux-2.6-2.orig/fs/fuse/inode.c
+++ linux-2.6-2/fs/fuse/inode.c
@@ -467,7 +467,7 @@ static struct fuse_conn *new_conn(void)
atomic_set(&fc->num_waiting, 0);
fc->bdi.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE;
fc->bdi.unplug_io_fn = default_unplug_io_fn;
- err = bdi_init(&fc->bdi);
+ err = bdi_init_fmt(&fc->bdi, "bdi-fuse-%llu", (unsigned long long)fc->id);
if (err) {
kfree(fc);
fc = NULL;
Index: linux-2.6-2/fs/nfs/client.c
===================================================================
--- linux-2.6-2.orig/fs/nfs/client.c
+++ linux-2.6-2/fs/nfs/client.c
@@ -678,7 +678,7 @@ static int nfs_probe_fsinfo(struct nfs_s
goto out_error;
nfs_server_set_fsinfo(server, &fsinfo);
- error = bdi_init(&server->backing_dev_info);
+ error = bdi_init_fmt(&server->backing_dev_info, "bdi-nfs-%s-%p", clp->cl_hostname, server);
if (error)
goto out_error;
Index: linux-2.6-2/include/linux/backing-dev.h
===================================================================
--- linux-2.6-2.orig/include/linux/backing-dev.h
+++ linux-2.6-2/include/linux/backing-dev.h
@@ -11,6 +11,8 @@
#include <linux/percpu_counter.h>
#include <linux/log2.h>
#include <linux/proportions.h>
+#include <linux/kernel.h>
+#include <linux/device.h>
#include <asm/atomic.h>
struct page;
@@ -48,11 +50,30 @@ struct backing_dev_info {
struct prop_local_percpu completions;
int dirty_exceeded;
+
+#ifdef CONFIG_SYSFS
+ struct device kdev;
+#endif
};
int bdi_init(struct backing_dev_info *bdi);
void bdi_destroy(struct backing_dev_info *bdi);
+int bdi_register(struct backing_dev_info *bdi, const char *fmt, ...);
+void bdi_unregister(struct backing_dev_info *bdi);
+
+#define bdi_init_fmt(bdi, fmt...) \
+ ({ \
+ int ret; \
+ ret = bdi_init(bdi); \
+ if (!ret) { \
+ ret = bdi_register(bdi, ##fmt); \
+ if (ret) \
+ bdi_destroy(bdi); \
+ } \
+ ret; \
+ })
+
static inline void __add_bdi_stat(struct backing_dev_info *bdi,
enum bdi_stat_item item, s64 amount)
{
Index: linux-2.6-2/include/linux/writeback.h
===================================================================
--- linux-2.6-2.orig/include/linux/writeback.h
+++ linux-2.6-2/include/linux/writeback.h
@@ -113,6 +113,9 @@ struct file;
int dirty_writeback_centisecs_handler(struct ctl_table *, int, struct file *,
void __user *, size_t *, loff_t *);
+void get_dirty_limits(long *pbackground, long *pdirty, long *pbdi_dirty,
+ struct backing_dev_info *bdi);
+
void page_writeback_init(void);
void balance_dirty_pages_ratelimited_nr(struct address_space *mapping,
unsigned long nr_pages_dirtied);
Index: linux-2.6-2/mm/backing-dev.c
===================================================================
--- linux-2.6-2.orig/mm/backing-dev.c
+++ linux-2.6-2/mm/backing-dev.c
@@ -4,12 +4,153 @@
#include <linux/fs.h>
#include <linux/sched.h>
#include <linux/module.h>
+#include <linux/writeback.h>
+#include <linux/device.h>
+
+#ifdef CONFIG_SYSFS
+
+static void bdi_release(struct device *dev)
+{
+}
+
+static int bdi_uevent(struct device *dev, struct kobj_uevent_env *env)
+{
+ return 0;
+}
+
+static struct class bdi_class = {
+ .name = "bdi",
+ .dev_release = bdi_release,
+ .dev_uevent = bdi_uevent,
+};
+
+static ssize_t readahead_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct backing_dev_info *bdi =
+ container_of(dev, struct backing_dev_info, kdev);
+ char *end;
+
+ bdi->ra_pages = simple_strtoul(buf, &end, 10);
+
+ return end - buf;
+}
+
+#define BDI_SHOW(name, expr) \
+static ssize_t name##_show(struct device *dev, \
+ struct device_attribute *attr, char *page) \
+{ \
+ struct backing_dev_info *bdi = \
+ container_of(dev, struct backing_dev_info, kdev); \
+ \
+ return snprintf(page, PAGE_SIZE-1, "%lld\n", (long long)expr); \
+}
+
+BDI_SHOW(readahead, bdi->ra_pages)
+
+BDI_SHOW(reclaimable, bdi_stat(bdi, BDI_RECLAIMABLE))
+BDI_SHOW(writeback, bdi_stat(bdi, BDI_WRITEBACK))
+
+static inline unsigned long get_dirty(struct backing_dev_info *bdi, int i)
+{
+ unsigned long thresh[3];
+
+ get_dirty_limits(&thresh[0], &thresh[1], &thresh[2], bdi);
+
+ return thresh[i];
+}
+
+BDI_SHOW(dirty, get_dirty(bdi, 1))
+BDI_SHOW(bdi_dirty, get_dirty(bdi, 2))
+
+static struct device_attribute bdi_dev_attrs[] = {
+ __ATTR(readahead, 0644, readahead_show, readahead_store),
+ __ATTR_RO(reclaimable),
+ __ATTR_RO(writeback),
+ __ATTR_RO(dirty),
+ __ATTR_RO(bdi_dirty),
+};
+
+static struct attribute *bdi_attributes[ARRAY_SIZE(bdi_dev_attrs) + 1];
+
+static struct attribute_group bdi_attribute_group = {
+ .attrs = bdi_attributes,
+};
+
+static struct attribute_group *bdi_attribute_groups[] = {
+ &bdi_attribute_group,
+ NULL,
+};
+
+static __init int bdi_class_init(void)
+{
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(bdi_dev_attrs); i++)
+ bdi_attributes[i] = &bdi_dev_attrs[i].attr;
+
+ return class_register(&bdi_class);
+}
+
+__initcall(bdi_class_init);
+
+int bdi_register(struct backing_dev_info *bdi, const char *fmt, ...)
+{
+ int ret;
+
+ bdi->kdev.class = &bdi_class;
+ bdi->kdev.groups = bdi_attribute_groups;
+ strcpy(bdi->kdev.bus_id, "bdi");
+ ret = device_register(&bdi->kdev);
+ if (!ret) {
+ char *name;
+ va_list args;
+
+ va_start(args, fmt);
+ name = kvprintf(fmt, args);
+ va_end(args);
+
+ if (!name) {
+ device_unregister(&bdi->kdev);
+ return -ENOMEM;
+ }
+
+ ret = device_rename(&bdi->kdev, name);
+ kfree(name);
+
+ if (!ret)
+ device_unregister(&bdi->kdev);
+ }
+
+ return ret;
+}
+
+void bdi_unregister(struct backing_dev_info *bdi)
+{
+ device_unregister(&bdi->kdev);
+}
+#else
+int bdi_register(struct backing_dev_info *bdi, const char *fmt, ...)
+{
+ return 0;
+}
+
+void bdi_unregister(struct backing_dev_info *bdi)
+{
+}
+#endif
+
+EXPORT_SYMBOL(bdi_register);
+EXPORT_SYMBOL(bdi_unregister);
int bdi_init(struct backing_dev_info *bdi)
{
int i, j;
int err;
+ memset(bdi, 0, sizeof(*bdi));
+
for (i = 0; i < NR_BDI_STAT_ITEMS; i++) {
err = percpu_counter_init_irq(&bdi->bdi_stat[i], 0);
if (err)
@@ -33,6 +174,8 @@ void bdi_destroy(struct backing_dev_info
{
int i;
+ bdi_unregister(bdi);
+
for (i = 0; i < NR_BDI_STAT_ITEMS; i++)
percpu_counter_destroy(&bdi->bdi_stat[i]);
@@ -90,3 +233,4 @@ long congestion_wait(int rw, long timeou
}
EXPORT_SYMBOL(congestion_wait);
+
Index: linux-2.6-2/mm/page-writeback.c
===================================================================
--- linux-2.6-2.orig/mm/page-writeback.c
+++ linux-2.6-2/mm/page-writeback.c
@@ -291,7 +291,7 @@ static unsigned long determine_dirtyable
return x + 1; /* Ensure that we never return 0 */
}
-static void
+void
get_dirty_limits(long *pbackground, long *pdirty, long *pbdi_dirty,
struct backing_dev_info *bdi)
{
Index: linux-2.6-2/block/genhd.c
===================================================================
--- linux-2.6-2.orig/block/genhd.c
+++ linux-2.6-2/block/genhd.c
@@ -182,6 +182,7 @@ void add_disk(struct gendisk *disk)
disk->minors, NULL, exact_match, exact_lock, disk);
register_disk(disk);
blk_register_queue(disk);
+ bdi_register(&disk->queue->backing_dev_info, "bdi-%s", disk->disk_name);
}
EXPORT_SYMBOL(add_disk);
@@ -190,6 +191,7 @@ EXPORT_SYMBOL(del_gendisk); /* in partit
void unlink_gendisk(struct gendisk *disk)
{
blk_unregister_queue(disk);
+ bdi_unregister(&disk->queue->backing_dev_info);
blk_unregister_region(MKDEV(disk->major, disk->first_minor),
disk->minors);
}
Index: linux-2.6-2/include/linux/string.h
===================================================================
--- linux-2.6-2.orig/include/linux/string.h
+++ linux-2.6-2/include/linux/string.h
@@ -8,6 +8,7 @@
#include <linux/compiler.h> /* for inline */
#include <linux/types.h> /* for size_t */
#include <linux/stddef.h> /* for NULL */
+#include <stdarg.h>
#ifdef __cplusplus
extern "C" {
@@ -111,6 +112,9 @@ extern void *kmemdup(const void *src, si
extern char **argv_split(gfp_t gfp, const char *str, int *argcp);
extern void argv_free(char **argv);
+char *kvprintf(const char *fmt, va_list args);
+char *kprintf(const char *fmt, ...);
+
#ifdef __cplusplus
}
#endif
Index: linux-2.6-2/mm/util.c
===================================================================
--- linux-2.6-2.orig/mm/util.c
+++ linux-2.6-2/mm/util.c
@@ -136,3 +136,45 @@ char *strndup_user(const char __user *s,
return p;
}
EXPORT_SYMBOL(strndup_user);
+
+char *kvprintf(const char *fmt, va_list args)
+{
+ char c;
+ char *buf;
+ int need;
+ int limit;
+ va_list args1;
+
+ va_copy(args1, args);
+ need = vsnprintf(&c, 1, fmt, args1);
+ va_end(args1);
+
+ /* Allocate the new space and copy the string in */
+ limit = need + 1;
+ buf = kmalloc(limit, GFP_KERNEL);
+ if (!buf)
+ return NULL;
+ need = vsnprintf(buf, limit, fmt, args);
+
+ /* something wrong with the string we copied? */
+ if (need >= limit) {
+ kfree(buf);
+ return NULL;
+ }
+
+ return buf;
+}
+EXPORT_SYMBOL(kvprintf);
+
+char *kprintf(const char *fmt, ...)
+{
+ char *buf;
+ va_list args;
+
+ va_start(args, fmt);
+ buf = kvprintf(fmt, args);
+ va_end(args);
+
+ return buf;
+}
+EXPORT_SYMBOL(kprintf);
-
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