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Message-Id: <1194009359.27652.377.camel@twins>
Date: Fri, 02 Nov 2007 14:15:59 +0100
From: Peter Zijlstra <peterz@...radead.org>
To: Kay Sievers <kay.sievers@...y.org>
Cc: Greg KH <greg@...ah.com>, Nick Piggin <nickpiggin@...oo.com.au>,
Andrew Morton <akpm@...ux-foundation.org>,
linux-kernel@...r.kernel.org, Jens Axboe <jens.axboe@...cle.com>,
Fengguang Wu <fengguang.wu@...il.com>,
Trond Myklebust <trond.myklebust@....uio.no>,
Miklos Szeredi <miklos@...redi.hu>
Subject: Re: per BDI dirty limit (was Re: -mm merge plans for 2.6.24)
Hi,
Thanks for the help so far, however we're still not quite there.
The below patch still has the funny 20 character name limit. Is there a
good reason its a char array like this, and not just a char * to a kstr?
The code does kstrdup all over the place, I can't imagine why suddenly
limiting it to 20 chars seems like a good idea.
Mounting NFS filesystems: mount: 192.168.0.1:/mnt/ying failed, reason given by server: Permission denied
mount: 192.168.0.1:/mnt/yang failed, reason given by server: Permission denied
[ 52.705052] sysfs: duplicate filename 'bdi-nfs-192.168.0.1' can not be created
[ 52.712517] WARNING: at /mnt/md0/src/linux-2.6-2/fs/sysfs/dir.c:424 sysfs_add_one()
[ 52.720243]
[ 52.720244] Call Trace:
[ 52.724311] [<ffffffff80304f7c>] sysfs_add_one+0xac/0xe0
[ 52.729708] [<ffffffff80305613>] create_dir+0x63/0xc0
[ 52.734832] [<ffffffff803056a4>] sysfs_create_dir+0x34/0x50
[ 52.740489] [<ffffffff804d5710>] _spin_unlock+0x30/0x60
[ 52.745792] [<ffffffff8036958e>] kobject_add+0xbe/0x200
[ 52.751094] [<ffffffff803dfc40>] device_add+0xc0/0x680
[ 52.756305] [<ffffffff803e0219>] device_register+0x19/0x20
[ 52.761877] [<ffffffff803e0697>] device_create+0xe7/0x120
[ 52.767360] [<ffffffff8036e0bc>] vsnprintf+0x2bc/0x690
[ 52.772585] [<ffffffff80370380>] kvasprintf+0x70/0x90
[ 52.777724] [<ffffffff80295bbb>] bdi_register+0x9b/0xe0
[ 52.783037] [<ffffffff8037e039>] percpu_counter_init_irq+0x39/0x50
[ 52.789299] [<ffffffff8036abcc>] prop_local_init_percpu+0x3c/0x50
[ 52.795462] [<ffffffff80295a41>] bdi_init+0x61/0xb0
[ 52.800411] [<ffffffff80308069>] nfs_probe_fsinfo+0x4d9/0x640
[ 52.806226] [<ffffffff80308f9a>] nfs_create_server+0x1ea/0x560
[ 52.812123] [<ffffffff80263526>] lock_release_holdtime+0x66/0x80
[ 52.818217] [<ffffffff802ca936>] __d_lookup+0x106/0x1d0
[ 52.823529] [<ffffffff802b0fd5>] __kmalloc_track_caller+0xa5/0x100
[ 52.829789] [<ffffffff80266185>] trace_hardirqs_on+0xd5/0x170
[ 52.835618] [<ffffffff80312412>] nfs_get_sb+0x2b2/0x740
[ 52.840931] [<ffffffff80312459>] nfs_get_sb+0x2f9/0x740
[ 52.846245] [<ffffffff802d0000>] __put_mnt_ns+0x90/0xa0
[ 52.851556] [<ffffffff802b89db>] vfs_kern_mount+0xbb/0x150
[ 52.857127] [<ffffffff802b8ade>] do_kern_mount+0x4e/0x100
[ 52.862614] [<ffffffff802d122c>] do_mount+0x4dc/0x7a0
[ 52.867751] [<ffffffff80266185>] trace_hardirqs_on+0xd5/0x170
[ 52.873580] [<ffffffff804d5842>] _spin_unlock_irqrestore+0x42/0x80
[ 52.879841] [<ffffffff8036c505>] __up_read+0x45/0xb0
[ 52.884894] [<ffffffff80255aa5>] search_exception_tables+0x25/0x40
[ 52.891155] [<ffffffff8028d1d5>] get_page_from_freelist+0x4a5/0x760
[ 52.897487] [<ffffffff8028a58f>] bad_range+0x1f/0x80
[ 52.902540] [<ffffffff8028d0b7>] get_page_from_freelist+0x387/0x760
[ 52.908888] [<ffffffff8028d54e>] __alloc_pages+0x6e/0x3b0
[ 52.914374] [<ffffffff802a80ea>] alloc_pages_current+0x5a/0x90
[ 52.920290] [<ffffffff8028c97b>] __get_free_pages+0x1b/0x40
[ 52.925929] [<ffffffff802cf892>] copy_mount_options+0x52/0x170
[ 52.931827] [<ffffffff802d1584>] sys_mount+0x94/0xe0
[ 52.936881] [<ffffffff804d49cd>] trace_hardirqs_on_thunk+0x35/0x3a
[ 52.943141] [<ffffffff8020c43e>] system_call+0x7e/0x83
[ 52.948357]
[ 52.949850] kobject_add failed for bdi-nfs-192.168.0.1 with -EEXIST, don't try to register things with the same name in the same directory.
[ 52.962332]
(just in case it wasn't obvious, the -%p part that was supposed to make
it unique got truncated)
---
block/genhd.c | 3 +
fs/fuse/inode.c | 3 -
fs/nfs/client.c | 3 -
include/linux/backing-dev.h | 19 +++++++
include/linux/writeback.h | 3 +
lib/percpu_counter.c | 1
mm/backing-dev.c | 107 ++++++++++++++++++++++++++++++++++++++++++++
mm/page-writeback.c | 2
8 files changed, 138 insertions(+), 3 deletions(-)
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 +182,8 @@ 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, NULL,
+ "bdi-%s", disk->disk_name);
}
EXPORT_SYMBOL(add_disk);
@@ -190,6 +192,7 @@ 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/fs/fuse/inode.c
===================================================================
--- linux-2.6-2.orig/fs/fuse/inode.c
+++ linux-2.6-2/fs/fuse/inode.c
@@ -467,7 +467,8 @@ 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, NULL,
+ "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 +678,8 @@ 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, NULL,
+ "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 +50,28 @@ struct backing_dev_info {
struct prop_local_percpu completions;
int dirty_exceeded;
+
+ struct device *dev;
};
int bdi_init(struct backing_dev_info *bdi);
void bdi_destroy(struct backing_dev_info *bdi);
+int bdi_register(struct backing_dev_info *bdi, struct device *parent,
+ const char *fmt, ...);
+void bdi_unregister(struct backing_dev_info *bdi);
+
+#define bdi_init_fmt(bdi, parent, fmt...) \
+ ({ \
+ int ret = bdi_init(bdi); \
+ if (!ret) { \
+ ret = bdi_register(bdi, parent, ##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 +4,115 @@
#include <linux/fs.h>
#include <linux/sched.h>
#include <linux/module.h>
+#include <linux/writeback.h>
+#include <linux/device.h>
+
+
+static struct class *bdi_class;
+
+static ssize_t readahead_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct backing_dev_info *bdi = dev_get_drvdata(dev);
+ 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 = dev_get_drvdata(dev); \
+ \
+ 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),
+ __ATTR_NULL,
+};
+
+static __init int bdi_class_init(void)
+{
+ bdi_class = class_create(THIS_MODULE, "bdi");
+ bdi_class->dev_attrs = bdi_dev_attrs;
+ return 0;
+}
+
+__initcall(bdi_class_init);
+
+int bdi_register(struct backing_dev_info *bdi, struct device *parent,
+ const char *fmt, ...)
+{
+ char *name;
+ va_list args;
+ int ret = 0;
+ struct device *dev;
+
+ va_start(args, fmt);
+ name = kvasprintf(GFP_KERNEL, fmt, args);
+ va_end(args);
+
+ if (!name)
+ return -ENOMEM;
+
+ dev = device_create(bdi_class, parent, MKDEV(0,0), name);
+ if (IS_ERR(dev)) {
+ ret = PTR_ERR(dev);
+ goto exit;
+ }
+
+ bdi->dev = dev;
+ dev_set_drvdata(bdi->dev, bdi);
+
+exit:
+ kfree(name);
+ return ret;
+}
+
+void bdi_unregister(struct backing_dev_info *bdi)
+{
+ if (bdi->dev) {
+ device_unregister(bdi->dev);
+ bdi->dev = NULL;
+ }
+}
+
+EXPORT_SYMBOL(bdi_register);
+EXPORT_SYMBOL(bdi_unregister);
int bdi_init(struct backing_dev_info *bdi)
{
int i, j;
int err;
+ bdi->dev = NULL;
+
for (i = 0; i < NR_BDI_STAT_ITEMS; i++) {
err = percpu_counter_init_irq(&bdi->bdi_stat[i], 0);
if (err)
@@ -33,6 +136,8 @@ 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]);
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/lib/percpu_counter.c
===================================================================
--- linux-2.6-2.orig/lib/percpu_counter.c
+++ linux-2.6-2/lib/percpu_counter.c
@@ -102,6 +102,7 @@ void percpu_counter_destroy(struct percp
return;
free_percpu(fbc->counters);
+ fbc->counters = NULL;
#ifdef CONFIG_HOTPLUG_CPU
mutex_lock(&percpu_counters_lock);
list_del(&fbc->list);
-
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