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authorChao Yu <chao@kernel.org>2025-07-31 13:34:04 +0800
committerJaegeuk Kim <jaegeuk@kernel.org>2025-08-11 17:03:27 +0000
commit3fcf228b6494e707aef960bad33461a513f16721 (patch)
tree499b07b73b70002be23fd146d47898aa6f34dd2d
parent8f5ae30d69d7543eee0d70083daf4de8fe15d585 (diff)
f2fs: dump more information when checkpoint was blocked for long time
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 <jprusakowski@google.com> Signed-off-by: Chao Yu <chao@kernel.org> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
-rw-r--r--fs/f2fs/checkpoint.c7
-rw-r--r--fs/f2fs/f2fs.h8
2 files changed, 14 insertions, 1 deletions
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 46be7560548c..7b567ab953e4 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 */