@@ -39,6 +39,19 @@ struct workqueue_struct *bdi_wq;
#include <linux/debugfs.h>
#include <linux/seq_file.h>
+struct wb_stats {
+ unsigned long nr_dirty;
+ unsigned long nr_io;
+ unsigned long nr_more_io;
+ unsigned long nr_dirty_time;
+ unsigned long nr_writeback;
+ unsigned long nr_reclaimable;
+ unsigned long nr_dirtied;
+ unsigned long nr_written;
+ unsigned long dirty_thresh;
+ unsigned long wb_thresh;
+};
+
static struct dentry *bdi_debug_root;
static void bdi_debug_init(void)
@@ -46,31 +59,68 @@ static void bdi_debug_init(void)
bdi_debug_root = debugfs_create_dir("bdi", NULL);
}
-static int bdi_debug_stats_show(struct seq_file *m, void *v)
+static void collect_wb_stats(struct wb_stats *stats,
+ struct bdi_writeback *wb)
{
- struct backing_dev_info *bdi = m->private;
- struct bdi_writeback *wb = &bdi->wb;
- unsigned long background_thresh;
- unsigned long dirty_thresh;
- unsigned long wb_thresh;
- unsigned long nr_dirty, nr_io, nr_more_io, nr_dirty_time;
struct inode *inode;
- nr_dirty = nr_io = nr_more_io = nr_dirty_time = 0;
spin_lock(&wb->list_lock);
list_for_each_entry(inode, &wb->b_dirty, i_io_list)
- nr_dirty++;
+ stats->nr_dirty++;
list_for_each_entry(inode, &wb->b_io, i_io_list)
- nr_io++;
+ stats->nr_io++;
list_for_each_entry(inode, &wb->b_more_io, i_io_list)
- nr_more_io++;
+ stats->nr_more_io++;
list_for_each_entry(inode, &wb->b_dirty_time, i_io_list)
if (inode->i_state & I_DIRTY_TIME)
- nr_dirty_time++;
+ stats->nr_dirty_time++;
spin_unlock(&wb->list_lock);
+ stats->nr_writeback += wb_stat(wb, WB_WRITEBACK);
+ stats->nr_reclaimable += wb_stat(wb, WB_RECLAIMABLE);
+ stats->nr_dirtied += wb_stat(wb, WB_DIRTIED);
+ stats->nr_written += wb_stat(wb, WB_WRITTEN);
+ stats->wb_thresh += wb_calc_thresh(wb, stats->dirty_thresh);
+}
+
+#ifdef CONFIG_CGROUP_WRITEBACK
+static void bdi_collect_stats(struct backing_dev_info *bdi,
+ struct wb_stats *stats)
+{
+ struct bdi_writeback *wb;
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(wb, &bdi->wb_list, bdi_node) {
+ if (!wb_tryget(wb))
+ continue;
+
+ collect_wb_stats(stats, wb);
+ wb_put(wb);
+ }
+ rcu_read_unlock();
+}
+#else
+static void bdi_collect_stats(struct backing_dev_info *bdi,
+ struct wb_stats *stats)
+{
+ collect_wb_stats(stats, &bdi->wb);
+}
+#endif
+
+static int bdi_debug_stats_show(struct seq_file *m, void *v)
+{
+ struct backing_dev_info *bdi = m->private;
+ unsigned long background_thresh;
+ unsigned long dirty_thresh;
+ struct wb_stats stats;
+ unsigned long tot_bw;
+
global_dirty_limits(&background_thresh, &dirty_thresh);
- wb_thresh = wb_calc_thresh(wb, dirty_thresh);
+
+ memset(&stats, 0, sizeof(stats));
+ stats.dirty_thresh = dirty_thresh;
+ bdi_collect_stats(bdi, &stats);
+ tot_bw = atomic_long_read(&bdi->tot_write_bandwidth);
seq_printf(m,
"BdiWriteback: %10lu kB\n"
@@ -87,18 +137,18 @@ static int bdi_debug_stats_show(struct seq_file *m, void *v)
"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(stats.nr_writeback),
+ K(stats.nr_reclaimable),
+ K(stats.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),
- nr_dirty,
- nr_io,
- nr_more_io,
- nr_dirty_time,
+ K(stats.nr_dirtied),
+ K(stats.nr_written),
+ K(tot_bw),
+ stats.nr_dirty,
+ stats.nr_io,
+ stats.nr_more_io,
+ stats.nr_dirty_time,
!list_empty(&bdi->bdi_list), bdi->wb.state);
return 0;
/sys/kernel/debug/bdi/xxx/stats is supposed to show writeback information of whole bdi, but only writeback information of bdi in root cgroup is collected. So writeback information in non-root cgroup are missing now. To be more specific, considering following case: /* create writeback cgroup */ cd /sys/fs/cgroup echo "+memory +io" > cgroup.subtree_control mkdir group1 cd group1 echo $$ > cgroup.procs /* do writeback in cgroup */ fio -name test -filename=/dev/vdb ... /* get writeback info of bdi */ cat /sys/kernel/debug/bdi/xxx/stats The cat result unexpectedly implies that there is no writeback on target bdi. Fix this by collecting stats of all wb in bdi instead of only wb in root cgroup. Following domain hierarchy is tested: global domain (320G) / \ cgroup domain1(10G) cgroup domain2(10G) | | bdi wb1 wb2 /* all writeback info of bdi is successfully collected */ cat stats BdiWriteback: 2912 kB BdiReclaimable: 1598464 kB BdiDirtyThresh: 167479028 kB DirtyThresh: 195038532 kB BackgroundThresh: 32466728 kB BdiDirtied: 19141696 kB BdiWritten: 17543456 kB BdiWriteBandwidth: 1136172 kBps b_dirty: 2 b_io: 0 b_more_io: 1 b_dirty_time: 0 bdi_list: 1 state: 1 Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com> Acked-by: Tejun Heo <tj@kernel.org> --- mm/backing-dev.c | 96 ++++++++++++++++++++++++++++++++++++------------ 1 file changed, 73 insertions(+), 23 deletions(-)