mm: bdi: move statistics to debugfs
Move BDI statistics to debugfs: /sys/kernel/debug/bdi/<bdi>/stats Use postcore_initcall() to initialize the sysfs class and debugfs, because debugfs is initialized in core_initcall(). Update descriptions in ABI documentation. 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>
This commit is contained in:
Miklos Szeredi
Linus Torvalds
parent
a42dde0415
commit
76f1418b48
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@ -3,8 +3,8 @@ Date: January 2008
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Contact: Peter Zijlstra <a.p.zijlstra@chello.nl>
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Description:
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Provide a place in sysfs for the backing_dev_info object.
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This allows us to see and set the various BDI specific variables.
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Provide a place in sysfs for the backing_dev_info object. This allows
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setting and retrieving various BDI specific variables.
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The <bdi> identifier can be either of the following:
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@ -26,34 +26,21 @@ read_ahead_kb (read-write)
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Size of the read-ahead window in kilobytes
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reclaimable_kb (read-only)
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Reclaimable (dirty or unstable) memory destined for writeback
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to this device
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writeback_kb (read-only)
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Memory currently under writeback to this device
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dirty_kb (read-only)
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Global threshold for reclaimable + writeback memory
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bdi_dirty_kb (read-only)
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Current threshold on this BDI for reclaimable + writeback
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memory
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min_ratio (read-write)
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Minimal percentage of global dirty threshold allocated to this
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bdi. If the value written to this file would make the the sum
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of all min_ratio values exceed 100, then EINVAL is returned.
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If min_ratio would become larger than the current max_ratio,
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then also EINVAL is returned. The default is zero
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Under normal circumstances each device is given a part of the
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total write-back cache that relates to its current average
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writeout speed in relation to the other devices.
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The 'min_ratio' parameter allows assigning a minimum
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percentage of the write-back cache to a particular device.
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For example, this is useful for providing a minimum QoS.
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max_ratio (read-write)
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Maximal percentage of global dirty threshold allocated to this
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bdi. If max_ratio would become smaller than the current
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min_ratio, then EINVAL is returned. The default is 100
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Allows limiting a particular device to use not more than the
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given percentage of the write-back cache. This is useful in
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situations where we want to avoid one device taking all or
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most of the write-back cache. For example in case of an NFS
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mount that is prone to get stuck, or a FUSE mount which cannot
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be trusted to play fair.
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@ -16,6 +16,7 @@
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struct page;
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struct device;
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struct dentry;
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/*
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* Bits in backing_dev_info.state
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@ -55,6 +56,11 @@ struct backing_dev_info {
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unsigned int max_ratio, max_prop_frac;
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struct device *dev;
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#ifdef CONFIG_DEBUG_FS
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struct dentry *debug_dir;
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struct dentry *debug_stats;
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#endif
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};
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int bdi_init(struct backing_dev_info *bdi);
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@ -10,6 +10,80 @@
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static struct class *bdi_class;
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#ifdef CONFIG_DEBUG_FS
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#include <linux/debugfs.h>
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#include <linux/seq_file.h>
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static struct dentry *bdi_debug_root;
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static void bdi_debug_init(void)
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{
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bdi_debug_root = debugfs_create_dir("bdi", NULL);
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}
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static int bdi_debug_stats_show(struct seq_file *m, void *v)
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{
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struct backing_dev_info *bdi = m->private;
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long background_thresh;
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long dirty_thresh;
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long bdi_thresh;
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get_dirty_limits(&background_thresh, &dirty_thresh, &bdi_thresh, bdi);
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#define K(x) ((x) << (PAGE_SHIFT - 10))
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seq_printf(m,
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"BdiWriteback: %8lu kB\n"
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"BdiReclaimable: %8lu kB\n"
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"BdiDirtyThresh: %8lu kB\n"
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"DirtyThresh: %8lu kB\n"
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"BackgroundThresh: %8lu kB\n",
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(unsigned long) K(bdi_stat(bdi, BDI_WRITEBACK)),
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(unsigned long) K(bdi_stat(bdi, BDI_RECLAIMABLE)),
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K(bdi_thresh),
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K(dirty_thresh),
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K(background_thresh));
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#undef K
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return 0;
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}
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static int bdi_debug_stats_open(struct inode *inode, struct file *file)
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{
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return single_open(file, bdi_debug_stats_show, inode->i_private);
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}
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static const struct file_operations bdi_debug_stats_fops = {
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.open = bdi_debug_stats_open,
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.read = seq_read,
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.llseek = seq_lseek,
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.release = single_release,
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};
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static void bdi_debug_register(struct backing_dev_info *bdi, const char *name)
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{
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bdi->debug_dir = debugfs_create_dir(name, bdi_debug_root);
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bdi->debug_stats = debugfs_create_file("stats", 0444, bdi->debug_dir,
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bdi, &bdi_debug_stats_fops);
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}
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static void bdi_debug_unregister(struct backing_dev_info *bdi)
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{
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debugfs_remove(bdi->debug_stats);
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debugfs_remove(bdi->debug_dir);
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}
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#else
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static inline void bdi_debug_init(void)
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{
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}
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static inline void bdi_debug_register(struct backing_dev_info *bdi,
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const char *name)
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{
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}
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static inline void bdi_debug_unregister(struct backing_dev_info *bdi)
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{
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}
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#endif
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static ssize_t read_ahead_kb_store(struct device *dev,
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struct device_attribute *attr,
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const char *buf, size_t count)
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@ -40,21 +114,6 @@ static ssize_t name##_show(struct device *dev, \
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BDI_SHOW(read_ahead_kb, K(bdi->ra_pages))
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BDI_SHOW(reclaimable_kb, K(bdi_stat(bdi, BDI_RECLAIMABLE)))
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BDI_SHOW(writeback_kb, K(bdi_stat(bdi, BDI_WRITEBACK)))
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static inline unsigned long get_dirty(struct backing_dev_info *bdi, int i)
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{
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unsigned long thresh[3];
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get_dirty_limits(&thresh[0], &thresh[1], &thresh[2], bdi);
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return thresh[i];
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}
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BDI_SHOW(dirty_kb, K(get_dirty(bdi, 1)))
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BDI_SHOW(bdi_dirty_kb, K(get_dirty(bdi, 2)))
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static ssize_t min_ratio_store(struct device *dev,
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struct device_attribute *attr, const char *buf, size_t count)
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{
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@ -95,10 +154,6 @@ BDI_SHOW(max_ratio, bdi->max_ratio)
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static struct device_attribute bdi_dev_attrs[] = {
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__ATTR_RW(read_ahead_kb),
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__ATTR_RO(reclaimable_kb),
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__ATTR_RO(writeback_kb),
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__ATTR_RO(dirty_kb),
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__ATTR_RO(bdi_dirty_kb),
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__ATTR_RW(min_ratio),
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__ATTR_RW(max_ratio),
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__ATTR_NULL,
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@ -108,10 +163,11 @@ static __init int bdi_class_init(void)
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{
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bdi_class = class_create(THIS_MODULE, "bdi");
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bdi_class->dev_attrs = bdi_dev_attrs;
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bdi_debug_init();
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return 0;
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}
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core_initcall(bdi_class_init);
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postcore_initcall(bdi_class_init);
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int bdi_register(struct backing_dev_info *bdi, struct device *parent,
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const char *fmt, ...)
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@ -136,6 +192,7 @@ int bdi_register(struct backing_dev_info *bdi, struct device *parent,
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bdi->dev = dev;
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dev_set_drvdata(bdi->dev, bdi);
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bdi_debug_register(bdi, name);
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exit:
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kfree(name);
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@ -152,6 +209,7 @@ EXPORT_SYMBOL(bdi_register_dev);
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void bdi_unregister(struct backing_dev_info *bdi)
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{
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if (bdi->dev) {
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bdi_debug_unregister(bdi);
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device_unregister(bdi->dev);
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bdi->dev = NULL;
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}
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