@@ -667,6 +667,18 @@ enum btrfs_exclusive_operation {
BTRFS_EXCLOP_SWAP_ACTIVATE,
};
+/* Storing data about btrfs commits. The data are accessible over sysfs */
+struct btrfs_commit_stats {
+ /* Total number of commits */
+ u64 commit_counter;
+ /* The maximum commit duration so far*/
+ u64 max_commit_dur;
+ /* The last commit duration */
+ u64 last_commit_dur;
+ /* The total commit duration */
+ u64 total_commit_dur;
+};
+
struct btrfs_fs_info {
u8 chunk_tree_uuid[BTRFS_UUID_SIZE];
unsigned long flags;
@@ -1076,6 +1088,8 @@ struct btrfs_fs_info {
spinlock_t zone_active_bgs_lock;
struct list_head zone_active_bgs;
+ struct btrfs_commit_stats commit_stats;
+
#ifdef CONFIG_BTRFS_FS_REF_VERIFY
spinlock_t ref_verify_lock;
struct rb_root block_tree;
@@ -10,6 +10,7 @@
#include <linux/pagemap.h>
#include <linux/blkdev.h>
#include <linux/uuid.h>
+#include <linux/timekeeping.h>
#include "misc.h"
#include "ctree.h"
#include "disk-io.h"
@@ -2084,12 +2085,23 @@ static void add_pending_snapshot(struct btrfs_trans_handle *trans)
list_add(&trans->pending_snapshot->list, &cur_trans->pending_snapshots);
}
+static void update_commit_stats(struct btrfs_fs_info *fs_info, ktime_t interval)
+{
+ fs_info->commit_stats.commit_counter++;
+ fs_info->commit_stats.last_commit_dur = interval;
+ fs_info->commit_stats.max_commit_dur = max_t(u64,
+ fs_info->commit_stats.max_commit_dur, interval);
+ fs_info->commit_stats.total_commit_dur += interval;
+}
+
int btrfs_commit_transaction(struct btrfs_trans_handle *trans)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
struct btrfs_transaction *cur_trans = trans->transaction;
struct btrfs_transaction *prev_trans = NULL;
int ret;
+ ktime_t start_time;
+ ktime_t interval;
ASSERT(refcount_read(&trans->use_count) == 1);
@@ -2214,6 +2226,12 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans)
}
}
+ /*
+ * Get the time spent on the work done by the commit thread and not
+ * the time spent waiting on a previous commit
+ */
+ start_time = ktime_get_ns();
+
extwriter_counter_dec(cur_trans, trans->type);
ret = btrfs_start_delalloc_flush(fs_info);
@@ -2455,6 +2473,8 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans)
trace_btrfs_transaction_commit(fs_info);
+ interval = ktime_get_ns() - start_time;
+
btrfs_scrub_continue(fs_info);
if (current->journal_info == trans)
@@ -2462,6 +2482,8 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans)
kmem_cache_free(btrfs_trans_handle_cachep, trans);
+ update_commit_stats(fs_info, interval);
+
return ret;
unlock_reloc:
First we add "struct btrfs_commit_stats" data structure under "fs_info" in fs/btrfs/ctree.h to store the commit stats for btrfs that will be exposed through sysfs. The stats exposed are: 1) The number of commits so far, 2) The duration of the last commit in ms, 3) The maximum commit duration seen so far in ms and 4) The total duration for all commits so far in ms. The update of the commit stats occurs after the commit thread has gone through all the logic that checks if there is another thread committing at the same time. This means that we only account for actual commit work in the commit stats we report and not the time the thread spends waiting until it is ready to do the commit work. Signed-off-by: Ioannis Angelakopoulos <iangelak@fb.com> --- fs/btrfs/ctree.h | 14 ++++++++++++++ fs/btrfs/transaction.c | 22 ++++++++++++++++++++++ 2 files changed, 36 insertions(+)