generic/299 w/ mode=lfs will cause long time latency of checkpoint,
let's dump more information once we hit case.
CP merge:
- Queued : 0
- Issued : 1
- Total : 1
- Cur time : 9765(ms)
- Peak time : 9765(ms)
F2FS-fs (vdc): blocked on checkpoint for 9765 ms
CPU: 11 UID: 0 PID: 237 Comm: kworker/u128:29 Tainted: G O
6.16.0-rc3+ #409 PREEMPT(voluntary)
Tainted: [O]=OOT_MODULE
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
1.16.3-debian-1.16.3-2 04/01/2014
Workqueue: writeback wb_workfn (flush-253:32)
Call Trace:
<TASK>
dump_stack_lvl+0x6e/0xa0
f2fs_issue_checkpoint+0x268/0x280
f2fs_write_node_pages+0x6a/0x2c0
do_writepages+0xd0/0x170
__writeback_single_inode+0x56/0x4c0
writeback_sb_inodes+0x22a/0x550
__writeback_inodes_wb+0x4c/0xf0
wb_writeback+0x300/0x400
wb_workfn+0x3de/0x500
process_one_work+0x230/0x5c0
worker_thread+0x1da/0x3d0
kthread+0x10d/0x250
ret_from_fork+0x164/0x190
ret_from_fork_asm+0x1a/0x30
Cc: Jan Prusakowski <jprusakow...@google.com>
Signed-off-by: Chao Yu <c...@kernel.org>
---
fs/f2fs/checkpoint.c | 7 +++++++
fs/f2fs/f2fs.h | 8 +++++++-
2 files changed, 14 insertions(+), 1 deletion(-)
diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
index db3831f7f2f5..02806e2edce4 100644
--- a/fs/f2fs/checkpoint.c
+++ b/fs/f2fs/checkpoint.c
@@ -1778,6 +1778,7 @@ static void __checkpoint_and_complete_reqs(struct
f2fs_sb_info *sbi)
llist_for_each_entry_safe(req, next, dispatch_list, llnode) {
diff = (u64)ktime_ms_delta(ktime_get(), req->queue_time);
req->ret = ret;
+ req->delta_time = diff;
complete(&req->wait);
sum_diff += diff;
@@ -1873,6 +1874,12 @@ int f2fs_issue_checkpoint(struct f2fs_sb_info *sbi)
else
flush_remained_ckpt_reqs(sbi, &req);
+ if (unlikely(req.delta_time >= CP_LONG_LATENCY_THRESHOLD)) {
+ f2fs_warn_ratelimited(sbi,
+ "blocked on checkpoint for %u ms", cprc->peak_time);
+ dump_stack();
+ }
+
return req.ret;
}
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index b9058518b54e..c036af1a885a 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -334,7 +334,10 @@ struct ckpt_req {
struct completion wait; /* completion for checkpoint done */
struct llist_node llnode; /* llist_node to be linked in wait
queue */
int ret; /* return code of checkpoint */
- ktime_t queue_time; /* request queued time */
+ union {
+ ktime_t queue_time; /* request queued time */
+ ktime_t delta_time; /* time in queue */
+ };
};
struct ckpt_req_control {
@@ -350,6 +353,9 @@ struct ckpt_req_control {
unsigned int peak_time; /* peak wait time in msec until now */
};
+/* a time threshold that checkpoint was blocked for, unit: ms */
+#define CP_LONG_LATENCY_THRESHOLD 5000
+
/* for the bitmap indicate blocks to be discarded */
struct discard_entry {
struct list_head list; /* list head */
--
2.49.0
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