UbiquitousOS
/
OpenCloudOS-Kernel
mirror of https://gitee.com/OpenCloudOS/OpenCloudOS-Kernel.git
11
0
Fork 0
Code Issues Projects Releases Wiki Activity

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>
This commit is contained in:
Josef Bacik 2020-10-09 09:28:19 -04:00 committed by David Sterba
parent 91e79a83ff
commit ac1ea10e75
2 changed files with 40 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

12
fs/btrfs/space-info.c
View File

@ -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);
}
/**

29
include/trace/events/btrfs.h
View File

@ -2026,6 +2026,35 @@ TRACE_EVENT(btrfs_convert_extent_bit,
__print_flags(__entry->clear_bits, "|", EXTENT_FLAGS))
);
TRACE_EVENT(btrfs_reserve_ticket,
TP_PROTO(const struct btrfs_fs_info *fs_info, u64 flags, u64 bytes,
u64 start_ns, int flush, int error),
TP_ARGS(fs_info, flags, bytes, start_ns, flush, error),
TP_STRUCT__entry_btrfs(
__field( u64, flags )
__field( u64, bytes )
__field( u64, start_ns )
__field( int, flush )
__field( int, error )
),
TP_fast_assign_btrfs(fs_info,
__entry->flags = flags;
__entry->bytes = bytes;
__entry->start_ns = start_ns;
__entry->flush = flush;
__entry->error = error;
),
TP_printk_btrfs("flags=%s bytes=%llu start_ns=%llu flush=%s error=%d",
__print_flags(__entry->flags, "|", BTRFS_GROUP_FLAGS),
__entry->bytes, __entry->start_ns,
__print_symbolic(__entry->flush, FLUSH_ACTIONS),
__entry->error)
);
DECLARE_EVENT_CLASS(btrfs_sleep_tree_lock,
TP_PROTO(const struct extent_buffer *eb, u64 start_ns),