Currently /sys/kernel/debug/bdi/$maj:$min/stats shows only root bdi wb. With CONFIG_CGROUP_WRITEBACK=y there is one for each memory cgroup.
This patch shows here state of each bdi_writeback in form: <global state> Id: 1 Cgroup: / <root wb state> Id: xxx Cgroup: /path <cgroup wb state> Id: yyy Cgroup: /path2 <cgroup wb state> ... Signed-off-by: Konstantin Khlebnikov <[email protected]> --- mm/backing-dev.c | 106 +++++++++++++++++++++++++++++++++++++++++++++++------- 1 file changed, 93 insertions(+), 13 deletions(-) diff --git a/mm/backing-dev.c b/mm/backing-dev.c index e8e89158adec..3e752c4bafaf 100644 --- a/mm/backing-dev.c +++ b/mm/backing-dev.c @@ -45,7 +45,7 @@ static void bdi_debug_init(void) static int bdi_debug_stats_show(struct seq_file *m, void *v) { struct backing_dev_info *bdi = m->private; - struct bdi_writeback *wb = &bdi->wb; + struct bdi_writeback *wb = v; unsigned long background_thresh; unsigned long dirty_thresh; unsigned long wb_thresh; @@ -65,43 +65,123 @@ static int bdi_debug_stats_show(struct seq_file *m, void *v) nr_dirty_time++; spin_unlock(&wb->list_lock); - global_dirty_limits(&background_thresh, &dirty_thresh); - wb_thresh = wb_calc_thresh(wb, dirty_thresh); - #define K(x) ((x) << (PAGE_SHIFT - 10)) + + /* global state */ + if (wb == &bdi->wb) { + global_dirty_limits(&background_thresh, &dirty_thresh); + wb_thresh = wb_calc_thresh(wb, dirty_thresh); + seq_printf(m, + "BdiDirtyThresh: %10lu kB\n" + "DirtyThresh: %10lu kB\n" + "BackgroundThresh: %10lu kB\n" + "bdi_list: %10u\n", + K(wb_thresh), + K(dirty_thresh), + K(background_thresh), + !list_empty(&bdi->bdi_list)); + } + + /* cgroup header */ +#ifdef CONFIG_CGROUP_WRITEBACK + if (bdi->capabilities & BDI_CAP_CGROUP_WRITEBACK) { + size_t buflen, len; + char *buf; + + seq_printf(m, "\nId: %d\nCgroup: ", wb->memcg_css->id); + buflen = seq_get_buf(m, &buf); + if (buf) { + len = cgroup_path(wb->memcg_css->cgroup, buf, buflen); + seq_commit(m, len <= buflen ? len : -1); + seq_putc(m, '\n'); + } + } +#endif /* CONFIG_CGROUP_WRITEBACK */ + seq_printf(m, "BdiWriteback: %10lu kB\n" "BdiReclaimable: %10lu kB\n" - "BdiDirtyThresh: %10lu kB\n" - "DirtyThresh: %10lu kB\n" - "BackgroundThresh: %10lu kB\n" "BdiDirtied: %10lu kB\n" "BdiWritten: %10lu kB\n" "BdiWriteBandwidth: %10lu kBps\n" + "BdiAvgWriteBwidth: %10lu kBps\n" "b_dirty: %10lu\n" "b_io: %10lu\n" "b_more_io: %10lu\n" "b_dirty_time: %10lu\n" - "bdi_list: %10u\n" "state: %10lx\n", (unsigned long) K(wb_stat(wb, WB_WRITEBACK)), (unsigned long) K(wb_stat(wb, WB_RECLAIMABLE)), - K(wb_thresh), - K(dirty_thresh), - K(background_thresh), (unsigned long) K(wb_stat(wb, WB_DIRTIED)), (unsigned long) K(wb_stat(wb, WB_WRITTEN)), (unsigned long) K(wb->write_bandwidth), + (unsigned long) K(wb->avg_write_bandwidth), nr_dirty, nr_io, nr_more_io, nr_dirty_time, - !list_empty(&bdi->bdi_list), bdi->wb.state); + wb->state); #undef K return 0; } -DEFINE_SHOW_ATTRIBUTE(bdi_debug_stats); + +static void *bdi_debug_stats_start(struct seq_file *m, loff_t *ppos) +{ + struct backing_dev_info *bdi = m->private; + struct bdi_writeback *wb; + loff_t pos = *ppos; + + rcu_read_lock(); + list_for_each_entry_rcu(wb, &bdi->wb_list, bdi_node) + if (pos-- == 0) + return wb; + return NULL; +} + +static void *bdi_debug_stats_next(struct seq_file *m, void *v, loff_t *ppos) +{ + struct backing_dev_info *bdi = m->private; + struct bdi_writeback *wb = v; + + list_for_each_entry_continue_rcu(wb, &bdi->wb_list, bdi_node) { + ++*ppos; + return wb; + } + return NULL; +} + +static void bdi_debug_stats_stop(struct seq_file *m, void *v) +{ + rcu_read_unlock(); +} + +static const struct seq_operations bdi_debug_stats_seq_ops = { + .start = bdi_debug_stats_start, + .next = bdi_debug_stats_next, + .stop = bdi_debug_stats_stop, + .show = bdi_debug_stats_show, +}; + +static int bdi_debug_stats_open(struct inode *inode, struct file *file) +{ + struct seq_file *m; + int ret; + + ret = seq_open(file, &bdi_debug_stats_seq_ops); + if (!ret) { + m = file->private_data; + m->private = inode->i_private; + } + return ret; +} + +static const struct file_operations bdi_debug_stats_fops = { + .open = bdi_debug_stats_open, + .read = seq_read, + .llseek = seq_lseek, + .release = seq_release, +}; static void bdi_debug_register(struct backing_dev_info *bdi, const char *name) {
