btrfs: sysfs: export commit stats

Export commit stats in file

  /sys/fs/btrfs/UUID/commit_stats

with example output like:

  commits 123
  last_commit_ms 11
  max_commit_ms 150
  total_commit_ms 2000

The values are in one file so reading them at a single time will give a
more consistent view. The stats are internally tracked in nanoseconds so
the cumulative values should not suffer from rounding errors.

Writing 0 to the file 'commit_stats' will reset max_commit_ms.
Initial values are set at first mount of the filesystem.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Ioannis Angelakopoulos <iangelak@fb.com>
[ update changelog ]
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Ioannis Angelakopoulos 2022-06-14 15:22:34 -07:00 committed by David Sterba
parent e55958c8a0
commit 140a8ff765

View file

@ -991,6 +991,48 @@ static ssize_t btrfs_sectorsize_show(struct kobject *kobj,
BTRFS_ATTR(, sectorsize, btrfs_sectorsize_show);
static ssize_t btrfs_commit_stats_show(struct kobject *kobj,
struct kobj_attribute *a, char *buf)
{
struct btrfs_fs_info *fs_info = to_fs_info(kobj);
return sysfs_emit(buf,
"commits %llu\n"
"last_commit_ms %llu\n"
"max_commit_ms %llu\n"
"total_commit_ms %llu\n",
fs_info->commit_stats.commit_count,
div_u64(fs_info->commit_stats.last_commit_dur, NSEC_PER_MSEC),
div_u64(fs_info->commit_stats.max_commit_dur, NSEC_PER_MSEC),
div_u64(fs_info->commit_stats.total_commit_dur, NSEC_PER_MSEC));
}
static ssize_t btrfs_commit_stats_store(struct kobject *kobj,
struct kobj_attribute *a,
const char *buf, size_t len)
{
struct btrfs_fs_info *fs_info = to_fs_info(kobj);
unsigned long val;
int ret;
if (!fs_info)
return -EPERM;
if (!capable(CAP_SYS_RESOURCE))
return -EPERM;
ret = kstrtoul(buf, 10, &val);
if (ret)
return ret;
if (val)
return -EINVAL;
WRITE_ONCE(fs_info->commit_stats.max_commit_dur, 0);
return len;
}
BTRFS_ATTR_RW(, commit_stats, btrfs_commit_stats_show, btrfs_commit_stats_store);
static ssize_t btrfs_clone_alignment_show(struct kobject *kobj,
struct kobj_attribute *a, char *buf)
{
@ -1230,6 +1272,7 @@ static const struct attribute *btrfs_attrs[] = {
BTRFS_ATTR_PTR(, generation),
BTRFS_ATTR_PTR(, read_policy),
BTRFS_ATTR_PTR(, bg_reclaim_threshold),
BTRFS_ATTR_PTR(, commit_stats),
NULL,
};
@ -2236,4 +2279,3 @@ void __cold btrfs_exit_sysfs(void)
#endif
kset_unregister(btrfs_kset);
}