f2fs: optimize trace_f2fs_write_checkpoint with enums

This patch optimizes the tracepoint by replacing these hardcoded strings
with a new enumeration f2fs_cp_phase.

1.Defines enum f2fs_cp_phase with values for each checkpoint phase.
2.Updates trace_f2fs_write_checkpoint to accept a u16 phase argument
instead of a string pointer.
3.Uses __print_symbolic in TP_printk to convert the enum values
back to their corresponding strings for human-readable trace output.

This change reduces the storage overhead for each trace event
by replacing a variable-length string with a 2-byte integer,
while maintaining the same readable output in ftrace.

Signed-off-by: YH Lin <yhli@google.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
index 4c401b5b29336b5bb3732b0a48b49421e5efaae1..300664269eb6241d4d5720e3f895ac2d4d949229 100644 (file)
--- a/fs/f2fs/checkpoint.c
+++ b/fs/f2fs/checkpoint.c
@@ -1673,7 +1673,7 @@ int f2fs_write_checkpoint(struct f2fs_sb_info *sbi, struct cp_control *cpc)
                goto out;
        }
 
-       trace_f2fs_write_checkpoint(sbi->sb, cpc->reason, "start block_ops");
+       trace_f2fs_write_checkpoint(sbi->sb, cpc->reason, CP_PHASE_START_BLOCK_OPS);
 
        err = block_operations(sbi);
        if (err)
@@ -1681,7 +1681,7 @@ int f2fs_write_checkpoint(struct f2fs_sb_info *sbi, struct cp_control *cpc)
 
        stat_cp_time(cpc, CP_TIME_OP_LOCK);
 
-       trace_f2fs_write_checkpoint(sbi->sb, cpc->reason, "finish block_ops");
+       trace_f2fs_write_checkpoint(sbi->sb, cpc->reason, CP_PHASE_FINISH_BLOCK_OPS);
 
        f2fs_flush_merged_writes(sbi);
 
@@ -1747,7 +1747,7 @@ stop:
 
        /* update CP_TIME to trigger checkpoint periodically */
        f2fs_update_time(sbi, CP_TIME);
-       trace_f2fs_write_checkpoint(sbi->sb, cpc->reason, "finish checkpoint");
+       trace_f2fs_write_checkpoint(sbi->sb, cpc->reason, CP_PHASE_FINISH_CHECKPOINT);
 out:
        if (cpc->reason != CP_RESIZE)
                f2fs_up_write(&sbi->cp_global_sem);

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 007195a1d4eb6b4914e2385a546dd14a1ce15e5f..20edbb99b814a7787be5514be794ff24fc65ac5e 100644 (file)
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -319,6 +319,12 @@ struct cp_control {
        struct cp_stats stats;
 };
 
+enum f2fs_cp_phase {
+       CP_PHASE_START_BLOCK_OPS,
+       CP_PHASE_FINISH_BLOCK_OPS,
+       CP_PHASE_FINISH_CHECKPOINT,
+};
+
 /*
  * indicate meta/data type
  */

diff --git a/include/trace/events/f2fs.h b/include/trace/events/f2fs.h
index e00611ead024ddbf1405e875bb48b3c9b7609740..df4017dcc7013bfe60b050271891aed1d1ce3334 100644 (file)
--- a/include/trace/events/f2fs.h
+++ b/include/trace/events/f2fs.h
@@ -50,6 +50,9 @@ TRACE_DEFINE_ENUM(CP_PAUSE);
 TRACE_DEFINE_ENUM(CP_RESIZE);
 TRACE_DEFINE_ENUM(EX_READ);
 TRACE_DEFINE_ENUM(EX_BLOCK_AGE);
+TRACE_DEFINE_ENUM(CP_PHASE_START_BLOCK_OPS);
+TRACE_DEFINE_ENUM(CP_PHASE_FINISH_BLOCK_OPS);
+TRACE_DEFINE_ENUM(CP_PHASE_FINISH_CHECKPOINT);
 
 #define show_block_type(type)                                          \
        __print_symbolic(type,                                          \
@@ -175,6 +178,12 @@ TRACE_DEFINE_ENUM(EX_BLOCK_AGE);
 #define S_ALL_PERM     (S_ISUID | S_ISGID | S_ISVTX |  \
                        S_IRWXU | S_IRWXG | S_IRWXO)
 
+#define show_cp_phase(phase)                                   \
+       __print_symbolic(phase,                                         \
+               { CP_PHASE_START_BLOCK_OPS,             "start block_ops" },                    \
+               { CP_PHASE_FINISH_BLOCK_OPS,    "finish block_ops" },                   \
+               { CP_PHASE_FINISH_CHECKPOINT,   "finish checkpoint" })
+
 struct f2fs_sb_info;
 struct f2fs_io_info;
 struct extent_info;
@@ -1573,26 +1582,26 @@ TRACE_EVENT(f2fs_readpages,
 
 TRACE_EVENT(f2fs_write_checkpoint,
 
-       TP_PROTO(struct super_block *sb, int reason, const char *msg),
+       TP_PROTO(struct super_block *sb, int reason, u16 phase),
 
-       TP_ARGS(sb, reason, msg),
+       TP_ARGS(sb, reason, phase),
 
        TP_STRUCT__entry(
                __field(dev_t,  dev)
                __field(int,    reason)
-               __string(dest_msg, msg)
+               __field(u16, phase)
        ),
 
        TP_fast_assign(
                __entry->dev            = sb->s_dev;
                __entry->reason         = reason;
-               __assign_str(dest_msg);
+               __entry->phase          = phase;
        ),
 
        TP_printk("dev = (%d,%d), checkpoint for %s, state = %s",
                show_dev(__entry->dev),
                show_cpreason(__entry->reason),
-               __get_str(dest_msg))
+               show_cp_phase(__entry->phase))
 );
 
 DECLARE_EVENT_CLASS(f2fs_discard,