[f2fs-dev] [PATCH v2 11/12] f2fs: cache: introduce tracepoints

[Chao Yu via Linux-f2fs-devel <linux-f2fs-devel@lists.sourceforge.net>]

This patch introduces ftrace tracepoints to observe and profile metadata
cache operations:
- trace_f2fs_cache_set_dirty to trace marking a cached block dirty
- trace_f2fs_write_cache to trace single block writeback submission
- trace_f2fs_write_caches to tracesbatch writeback and sync sessions

Signed-off-by: Chao Yu <chao@kernel.org>
---
 fs/f2fs/cache.c             |  3 ++
 fs/f2fs/checkpoint.c        |  6 ++++
 fs/f2fs/segment.c           |  3 ++
 include/trace/events/f2fs.h | 71 +++++++++++++++++++++++++++++++++++++
 4 files changed, 83 insertions(+)

diff --git a/fs/f2fs/cache.c b/fs/f2fs/cache.c
index 9a9d62283ae0..b2bdc634a6de 100644
--- a/fs/f2fs/cache.c
+++ b/fs/f2fs/cache.c
@@ -15,6 +15,7 @@
 #include "f2fs.h"
 #include "cache.h"
 #include "node.h"
+#include <trace/events/f2fs.h>
 #include "segment.h"
 
 void f2fs_cache_wait_writeback_cond(struct f2fs_cached_block *entry,
@@ -76,6 +77,8 @@ bool f2fs_mark_cache_dirty(struct f2fs_cached_block *entry)
 		enum count_type type = IS_META_CACHE(cache) ?
 				F2FS_DIRTY_META : F2FS_DIRTY_NODES;
 
+		trace_f2fs_cache_set_dirty(entry,
+				IS_META_CACHE(cache) ? META : NODE);
 		f2fs_cache_update_tag(entry, F2FS_CACHE_TAG_NONE,
 						F2FS_CACHE_TAG_DIRTY);
 		inc_page_count(cache->sbi, type);
diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
index 977dd1f08f24..182be9e49f34 100644
--- a/fs/f2fs/checkpoint.c
+++ b/fs/f2fs/checkpoint.c
@@ -551,6 +551,8 @@ static bool __f2fs_write_meta_cache(struct f2fs_cached_block *entry,
 {
 	struct f2fs_sb_info *sbi = entry->cache->sbi;
 
+	trace_f2fs_write_cache(entry, META);
+
 	if (unlikely(f2fs_cp_error(sbi))) {
 		if (is_sbi_flag_set(sbi, SBI_IS_CLOSE)) {
 			f2fs_force_clear_cache_dirty(entry);
@@ -609,6 +611,8 @@ long f2fs_sync_meta_caches(struct f2fs_sb_info *sbi, long nr_to_write,
 	struct blk_plug plug;
 	bool background = nr_to_write != LONG_MAX;
 
+	trace_f2fs_write_caches(sbi, nr_to_write, 0, META);
+
 	blk_start_plug(&plug);
 
 	while ((nr = f2fs_cache_gang_lookup_tag(META_CACHE(sbi), entries,
@@ -664,6 +668,8 @@ long f2fs_sync_meta_caches(struct f2fs_sb_info *sbi, long nr_to_write,
 
 	blk_finish_plug(&plug);
 
+	trace_f2fs_write_caches(sbi, nr_to_write, nwritten, META);
+
 	return nwritten;
 }
 
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index e526e2ec7d3f..b710d322437f 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -4170,6 +4170,9 @@ void f2fs_do_write_node_page(unsigned int nid, struct f2fs_io_info *fio)
 {
 	struct f2fs_summary sum;
 
+	if (fio->is_cache)
+		trace_f2fs_write_cache(fio->cache_entry, NODE);
+
 	set_summary(&sum, nid, 0, 0);
 	do_write_page(&sum, fio);
 
diff --git a/include/trace/events/f2fs.h b/include/trace/events/f2fs.h
index d53be932df01..df4cd346ae72 100644
--- a/include/trace/events/f2fs.h
+++ b/include/trace/events/f2fs.h
@@ -1430,6 +1430,50 @@ DEFINE_EVENT(f2fs__folio, f2fs_set_page_dirty,
 	TP_ARGS(folio, type)
 );
 
+DECLARE_EVENT_CLASS(f2fs__cached_block,
+
+	TP_PROTO(struct f2fs_cached_block *block, int type),
+
+	TP_ARGS(block, type),
+
+	TP_STRUCT__entry(
+		__field(dev_t,	dev)
+		__field(pgoff_t, index)
+		__field(int,	type)
+		__field(int,	dirty)
+		__field(int,	uptodate)
+	),
+
+	TP_fast_assign(
+		__entry->dev	= block->cache->sbi->sb->s_dev;
+		__entry->index	= block->index;
+		__entry->type	= type;
+		__entry->dirty	= f2fs_cache_test_dirty(block);
+		__entry->uptodate = f2fs_cache_test_uptodate(block);
+	),
+
+	TP_printk("dev = (%d,%d), %s, index = %lu, dirty = %d, uptodate = %d",
+		show_dev(__entry->dev),
+		show_block_type(__entry->type),
+		(unsigned long)__entry->index,
+		__entry->dirty,
+		__entry->uptodate)
+);
+
+DEFINE_EVENT(f2fs__cached_block, f2fs_write_cache,
+
+	TP_PROTO(struct f2fs_cached_block *block, int type),
+
+	TP_ARGS(block, type)
+);
+
+DEFINE_EVENT(f2fs__cached_block, f2fs_cache_set_dirty,
+
+	TP_PROTO(struct f2fs_cached_block *block, int type),
+
+	TP_ARGS(block, type)
+);
+
 TRACE_EVENT(f2fs_replace_atomic_write_block,
 
 	TP_PROTO(struct inode *inode, struct inode *cow_inode, pgoff_t index,
@@ -1574,6 +1618,33 @@ TRACE_EVENT(f2fs_writepages,
 		__entry->for_sync)
 );
 
+TRACE_EVENT(f2fs_write_caches,
+
+	TP_PROTO(struct f2fs_sb_info *sbi, long nr_to_write, long nwritten, int type),
+
+	TP_ARGS(sbi, nr_to_write, nwritten, type),
+
+	TP_STRUCT__entry(
+		__field(dev_t,	dev)
+		__field(long,	nr_to_write)
+		__field(long,	nwritten)
+		__field(int,	type)
+	),
+
+	TP_fast_assign(
+		__entry->dev		= sbi->sb->s_dev;
+		__entry->nr_to_write	= nr_to_write;
+		__entry->nwritten	= nwritten;
+		__entry->type		= type;
+	),
+
+	TP_printk("dev = (%d,%d), %s, nr_to_write = %ld, nwritten = %ld",
+		show_dev(__entry->dev),
+		show_block_type(__entry->type),
+		__entry->nr_to_write,
+		__entry->nwritten)
+);
+
 TRACE_EVENT(f2fs_readpages,
 
 	TP_PROTO(struct inode *inode, pgoff_t start, unsigned int nrpage),
-- 
2.49.0



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