* [f2fs-dev] [PATCH 2/2] f2fs: add time stats of checkpoint for debug
2025-07-31 5:34 [f2fs-dev] [PATCH 1/2] f2fs: dump more information when checkpoint was blocked for long time Chao Yu via Linux-f2fs-devel
@ 2025-07-31 5:34 ` Chao Yu via Linux-f2fs-devel
2025-08-15 16:40 ` [f2fs-dev] [PATCH 1/2] f2fs: dump more information when checkpoint was blocked for long time patchwork-bot+f2fs--- via Linux-f2fs-devel
1 sibling, 0 replies; 3+ messages in thread
From: Chao Yu via Linux-f2fs-devel @ 2025-07-31 5:34 UTC (permalink / raw)
To: jaegeuk; +Cc: linux-kernel, linux-f2fs-devel
checkpoint was blocked for 18643 ms
Step 0: 0 ms
Step 1: 38 ms
Step 2: 63 ms
Step 3: 4 ms
Step 4: 0 ms
Step 5: 0 ms
Step 6: 9 ms
Step 7: 0 ms
Step 8: 18277 ms
Step 9: 249 ms
Cc: Jan Prusakowski <jprusakowski@google.com>
Signed-off-by: Chao Yu <chao@kernel.org>
---
fs/f2fs/checkpoint.c | 46 ++++++++++++++++++++++++++++++++++++++++++++
fs/f2fs/f2fs.h | 22 +++++++++++++++++++++
2 files changed, 68 insertions(+)
diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
index 02806e2edce4..bbe07e3a6c75 100644
--- a/fs/f2fs/checkpoint.c
+++ b/fs/f2fs/checkpoint.c
@@ -1442,6 +1442,34 @@ u64 f2fs_get_sectors_written(struct f2fs_sb_info *sbi)
return get_sectors_written(sbi->sb->s_bdev);
}
+static inline void stat_cp_time(struct cp_control *cpc, enum cp_time type)
+{
+ cpc->stats.times[type] = ktime_get();
+}
+
+static inline void check_cp_time(struct f2fs_sb_info *sbi, struct cp_control *cpc)
+{
+ unsigned long long sb_diff, cur_diff;
+ enum cp_time ct;
+
+ sb_diff = (u64)ktime_ms_delta(sbi->cp_stats.times[CP_TIME_END],
+ sbi->cp_stats.times[CP_TIME_START]);
+ cur_diff = (u64)ktime_ms_delta(cpc->stats.times[CP_TIME_END],
+ cpc->stats.times[CP_TIME_START]);
+
+ if (cur_diff > sb_diff) {
+ sbi->cp_stats = cpc->stats;
+ if (cur_diff < CP_LONG_LATENCY_THRESHOLD)
+ return;
+
+ f2fs_warn(sbi, "checkpoint was blocked for %llu ms", cur_diff);
+ for (ct = CP_TIME_START; ct < CP_TIME_MAX - 1; ct++)
+ f2fs_warn(sbi, "Step#%d: %llu ms", ct,
+ (u64)ktime_ms_delta(cpc->stats.times[ct + 1],
+ cpc->stats.times[ct]));
+ }
+}
+
static int do_checkpoint(struct f2fs_sb_info *sbi, struct cp_control *cpc)
{
struct f2fs_checkpoint *ckpt = F2FS_CKPT(sbi);
@@ -1459,6 +1487,8 @@ static int do_checkpoint(struct f2fs_sb_info *sbi, struct cp_control *cpc)
/* Flush all the NAT/SIT pages */
f2fs_sync_meta_pages(sbi, META, LONG_MAX, FS_CP_META_IO);
+ stat_cp_time(cpc, CP_TIME_SYNC_META);
+
/* start to update checkpoint, cp ver is already updated previously */
ckpt->elapsed_time = cpu_to_le64(get_mtime(sbi, true));
ckpt->free_segment_count = cpu_to_le32(free_segments(sbi));
@@ -1555,20 +1585,26 @@ static int do_checkpoint(struct f2fs_sb_info *sbi, struct cp_control *cpc)
/* Here, we have one bio having CP pack except cp pack 2 page */
f2fs_sync_meta_pages(sbi, META, LONG_MAX, FS_CP_META_IO);
+ stat_cp_time(cpc, CP_TIME_SYNC_CP_META);
+
/* Wait for all dirty meta pages to be submitted for IO */
f2fs_wait_on_all_pages(sbi, F2FS_DIRTY_META);
+ stat_cp_time(cpc, CP_TIME_WAIT_DIRTY_META);
/* wait for previous submitted meta pages writeback */
f2fs_wait_on_all_pages(sbi, F2FS_WB_CP_DATA);
+ stat_cp_time(cpc, CP_TIME_WAIT_CP_DATA);
/* flush all device cache */
err = f2fs_flush_device_cache(sbi);
if (err)
return err;
+ stat_cp_time(cpc, CP_TIME_FLUSH_DEVICE);
/* barrier and flush checkpoint cp pack 2 page if it can */
commit_checkpoint(sbi, ckpt, start_blk);
f2fs_wait_on_all_pages(sbi, F2FS_WB_CP_DATA);
+ stat_cp_time(cpc, CP_TIME_WAIT_LAST_CP);
/*
* invalidate intermediate page cache borrowed from meta inode which are
@@ -1613,6 +1649,8 @@ int f2fs_write_checkpoint(struct f2fs_sb_info *sbi, struct cp_control *cpc)
unsigned long long ckpt_ver;
int err = 0;
+ stat_cp_time(cpc, CP_TIME_START);
+
if (f2fs_readonly(sbi->sb) || f2fs_hw_is_readonly(sbi))
return -EROFS;
@@ -1624,6 +1662,8 @@ int f2fs_write_checkpoint(struct f2fs_sb_info *sbi, struct cp_control *cpc)
if (cpc->reason != CP_RESIZE)
f2fs_down_write(&sbi->cp_global_sem);
+ stat_cp_time(cpc, CP_TIME_LOCK);
+
if (!is_sbi_flag_set(sbi, SBI_IS_DIRTY) &&
((cpc->reason & CP_FASTBOOT) || (cpc->reason & CP_SYNC) ||
((cpc->reason & CP_DISCARD) && !sbi->discard_blks)))
@@ -1639,6 +1679,8 @@ int f2fs_write_checkpoint(struct f2fs_sb_info *sbi, struct cp_control *cpc)
if (err)
goto out;
+ stat_cp_time(cpc, CP_TIME_OP_LOCK);
+
trace_f2fs_write_checkpoint(sbi->sb, cpc->reason, "finish block_ops");
f2fs_flush_merged_writes(sbi);
@@ -1678,6 +1720,8 @@ int f2fs_write_checkpoint(struct f2fs_sb_info *sbi, struct cp_control *cpc)
f2fs_flush_sit_entries(sbi, cpc);
+ stat_cp_time(cpc, CP_TIME_FLUSH_META);
+
/* save inmem log status */
f2fs_save_inmem_curseg(sbi);
@@ -1695,6 +1739,8 @@ int f2fs_write_checkpoint(struct f2fs_sb_info *sbi, struct cp_control *cpc)
stat_inc_cp_count(sbi);
stop:
unblock_operations(sbi);
+ stat_cp_time(cpc, CP_TIME_END);
+ check_cp_time(sbi, cpc);
if (cpc->reason & CP_RECOVERY)
f2fs_notice(sbi, "checkpoint: version = %llx", ckpt_ver);
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index c036af1a885a..691af2a6c159 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -269,11 +269,32 @@ enum {
#define DEF_DISABLE_QUICK_INTERVAL 1 /* 1 secs */
#define DEF_UMOUNT_DISCARD_TIMEOUT 5 /* 5 secs */
+enum cp_time {
+ CP_TIME_START, /* begin */
+ CP_TIME_LOCK, /* after cp_global_sem */
+ CP_TIME_OP_LOCK, /* after block_operation */
+ CP_TIME_FLUSH_META, /* after flush sit/nat */
+ CP_TIME_SYNC_META, /* after sync_meta_pages */
+ CP_TIME_SYNC_CP_META, /* after sync cp meta pages */
+ CP_TIME_WAIT_DIRTY_META,/* after wait on dirty meta */
+ CP_TIME_WAIT_CP_DATA, /* after wait on cp data */
+ CP_TIME_FLUSH_DEVICE, /* after flush device cache */
+ CP_TIME_WAIT_LAST_CP, /* after wait on last cp pack */
+ CP_TIME_END, /* after unblock_operation */
+ CP_TIME_MAX,
+};
+
+/* time cost stats of checkpoint */
+struct cp_stats {
+ ktime_t times[CP_TIME_MAX];
+};
+
struct cp_control {
int reason;
__u64 trim_start;
__u64 trim_end;
__u64 trim_minlen;
+ struct cp_stats stats;
};
/*
@@ -1650,6 +1671,7 @@ struct f2fs_sb_info {
unsigned long last_time[MAX_TIME]; /* to store time in jiffies */
long interval_time[MAX_TIME]; /* to store thresholds */
struct ckpt_req_control cprc_info; /* for checkpoint request control */
+ struct cp_stats cp_stats; /* for time stat of checkpoint */
struct inode_management im[MAX_INO_ENTRY]; /* manage inode cache */
--
2.49.0
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