diff options
| author | Josef Bacik <josef@toxicpanda.com> | 2020-10-09 15:28:19 +0200 |
|---|---|---|
| committer | David Sterba <dsterba@suse.com> | 2021-02-08 22:58:58 +0100 |
| commit | ac1ea10e757a57fb61512ae9beb2ef67e5340e31 (patch) | |
| tree | dab384f192cb229fcbe3929615fb502cb2debc63 /fs/btrfs/space-info.c | |
| parent | btrfs: make flush_space take a enum btrfs_flush_state instead of int (diff) | |
| download | linux-ac1ea10e757a57fb61512ae9beb2ef67e5340e31.tar.xz linux-ac1ea10e757a57fb61512ae9beb2ef67e5340e31.zip | |
btrfs: add a trace point for reserve tickets
While debugging a ENOSPC related performance problem I needed to see the
time difference between start and end of a reserve ticket, so add a
trace point to report when we handle a reserve ticket.
I opted to spit out start_ns itself without calculating the difference
because there could be a gap between enabling the tracepoint and setting
start_ns. Doing it this way allows us to filter on 0 start_ns so we
don't get bogus entries, and we can easily calculate the time difference
with bpftrace or something else.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs/btrfs/space-info.c')
| -rw-r--r-- | fs/btrfs/space-info.c | 12 |
1 files changed, 11 insertions, 1 deletions
diff --git a/fs/btrfs/space-info.c b/fs/btrfs/space-info.c index 4eab581b1b9c..d879e3fea0b6 100644 --- a/fs/btrfs/space-info.c +++ b/fs/btrfs/space-info.c @@ -1220,6 +1220,8 @@ static void wait_reserve_ticket(struct btrfs_fs_info *fs_info, * @fs_info: the filesystem * @space_info: space info for the reservation * @ticket: ticket for the reservation + * @start_ns: timestamp when the reservation started + * @orig_bytes: amount of bytes originally reserved * @flush: how much we can flush * * This does the work of figuring out how to flush for the ticket, waiting for @@ -1228,6 +1230,7 @@ static void wait_reserve_ticket(struct btrfs_fs_info *fs_info, static int handle_reserve_ticket(struct btrfs_fs_info *fs_info, struct btrfs_space_info *space_info, struct reserve_ticket *ticket, + u64 start_ns, u64 orig_bytes, enum btrfs_reserve_flush_enum flush) { int ret; @@ -1283,6 +1286,8 @@ static int handle_reserve_ticket(struct btrfs_fs_info *fs_info, * space wasn't reserved at all). */ ASSERT(!(ticket->bytes == 0 && ticket->error)); + trace_btrfs_reserve_ticket(fs_info, space_info->flags, orig_bytes, + start_ns, flush, ticket->error); return ret; } @@ -1317,6 +1322,7 @@ static int __reserve_bytes(struct btrfs_fs_info *fs_info, { struct work_struct *async_work; struct reserve_ticket ticket; + u64 start_ns = 0; u64 used; int ret = 0; bool pending_tickets; @@ -1369,6 +1375,9 @@ static int __reserve_bytes(struct btrfs_fs_info *fs_info, space_info->reclaim_size += ticket.bytes; init_waitqueue_head(&ticket.wait); ticket.steal = (flush == BTRFS_RESERVE_FLUSH_ALL_STEAL); + if (trace_btrfs_reserve_ticket_enabled()) + start_ns = ktime_get_ns(); + if (flush == BTRFS_RESERVE_FLUSH_ALL || flush == BTRFS_RESERVE_FLUSH_ALL_STEAL || flush == BTRFS_RESERVE_FLUSH_DATA) { @@ -1405,7 +1414,8 @@ static int __reserve_bytes(struct btrfs_fs_info *fs_info, if (!ret || flush == BTRFS_RESERVE_NO_FLUSH) return ret; - return handle_reserve_ticket(fs_info, space_info, &ticket, flush); + return handle_reserve_ticket(fs_info, space_info, &ticket, start_ns, + orig_bytes, flush); } /** |