Message-ID: <Yn1zPQKZ3DI6e1Zi@google.com>
Date:   Thu, 12 May 2022 13:51:09 -0700
From:   Jaegeuk Kim <jaegeuk@...nel.org>
To:     linux-kernel@...r.kernel.org,
        linux-f2fs-devel@...ts.sourceforge.net
Subject: Re: [PATCH 2/5 v2] f2fs: introduce f2fs_gc_control to consolidate
 f2fs_gc parameters

No functional change.

- remove checkpoint=disable check for f2fs_write_checkpoint
- get sec_freed all the time

Reviewed-by: Chao Yu <chao@...nel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@...nel.org>
---

 Change log from v1:
  - clean up more

 fs/f2fs/f2fs.h              | 11 +++++-
 fs/f2fs/file.c              | 30 ++++++++++++---
 fs/f2fs/gc.c                | 74 ++++++++++++++++++++-----------------
 fs/f2fs/segment.c           |  8 +++-
 fs/f2fs/super.c             |  8 +++-
 include/trace/events/f2fs.h | 18 ++++-----
 6 files changed, 98 insertions(+), 51 deletions(-)

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 0699d7460d5d..9920b2d6af8f 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -1265,6 +1265,14 @@ struct atgc_management {
 	unsigned long long age_threshold;	/* age threshold */
 };
 
+struct f2fs_gc_control {
+	unsigned int victim_segno;	/* target victim segment number */
+	int init_gc_type;		/* FG_GC or BG_GC */
+	bool no_bg_gc;			/* check the space and stop bg_gc */
+	bool should_migrate_blocks;	/* should migrate blocks */
+	bool err_gc_skipped;		/* return EAGAIN if GC skipped */
+};
+
 /* For s_flag in struct f2fs_sb_info */
 enum {
 	SBI_IS_DIRTY,				/* dirty flag for checkpoint */
@@ -3761,8 +3769,7 @@ extern const struct iomap_ops f2fs_iomap_ops;
 int f2fs_start_gc_thread(struct f2fs_sb_info *sbi);
 void f2fs_stop_gc_thread(struct f2fs_sb_info *sbi);
 block_t f2fs_start_bidx_of_node(unsigned int node_ofs, struct inode *inode);
-int f2fs_gc(struct f2fs_sb_info *sbi, bool sync, bool background, bool force,
-			unsigned int segno);
+int f2fs_gc(struct f2fs_sb_info *sbi, struct f2fs_gc_control *gc_control);
 void f2fs_build_gc_manager(struct f2fs_sb_info *sbi);
 int f2fs_resize_fs(struct f2fs_sb_info *sbi, __u64 block_count);
 int __init f2fs_create_garbage_collection_cache(void);
diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index 6da8a663de7b..d0547bef0851 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -1647,6 +1647,10 @@ static int expand_inode_data(struct inode *inode, loff_t offset,
 	struct f2fs_map_blocks map = { .m_next_pgofs = NULL,
 			.m_next_extent = NULL, .m_seg_type = NO_CHECK_TYPE,
 			.m_may_create = true };
+	struct f2fs_gc_control gc_control = { .victim_segno = NULL_SEGNO,
+			.init_gc_type = FG_GC,
+			.should_migrate_blocks = false,
+			.err_gc_skipped = true };
 	pgoff_t pg_start, pg_end;
 	loff_t new_size = i_size_read(inode);
 	loff_t off_end;
@@ -1684,7 +1688,7 @@ static int expand_inode_data(struct inode *inode, loff_t offset,
 		if (has_not_enough_free_secs(sbi, 0,
 			GET_SEC_FROM_SEG(sbi, overprovision_segments(sbi)))) {
 			f2fs_down_write(&sbi->gc_lock);
-			err = f2fs_gc(sbi, true, false, false, NULL_SEGNO);
+			err = f2fs_gc(sbi, &gc_control);
 			if (err && err != -ENODATA)
 				goto out_err;
 		}
@@ -2344,6 +2348,9 @@ static int f2fs_ioc_gc(struct file *filp, unsigned long arg)
 {
 	struct inode *inode = file_inode(filp);
 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
+	struct f2fs_gc_control gc_control = { .victim_segno = NULL_SEGNO,
+			.no_bg_gc = false,
+			.should_migrate_blocks = false };
 	__u32 sync;
 	int ret;
 
@@ -2369,7 +2376,9 @@ static int f2fs_ioc_gc(struct file *filp, unsigned long arg)
 		f2fs_down_write(&sbi->gc_lock);
 	}
 
-	ret = f2fs_gc(sbi, sync, true, false, NULL_SEGNO);
+	gc_control.init_gc_type = sync ? FG_GC : BG_GC;
+	gc_control.err_gc_skipped = sync;
+	ret = f2fs_gc(sbi, &gc_control);
 out:
 	mnt_drop_write_file(filp);
 	return ret;
@@ -2378,6 +2387,11 @@ static int f2fs_ioc_gc(struct file *filp, unsigned long arg)
 static int __f2fs_ioc_gc_range(struct file *filp, struct f2fs_gc_range *range)
 {
 	struct f2fs_sb_info *sbi = F2FS_I_SB(file_inode(filp));
+	struct f2fs_gc_control gc_control = {
+			.init_gc_type = range->sync ? FG_GC : BG_GC,
+			.no_bg_gc = false,
+			.should_migrate_blocks = false,
+			.err_gc_skipped = range->sync };
 	u64 end;
 	int ret;
 
@@ -2405,8 +2419,8 @@ static int __f2fs_ioc_gc_range(struct file *filp, struct f2fs_gc_range *range)
 		f2fs_down_write(&sbi->gc_lock);
 	}
 
-	ret = f2fs_gc(sbi, range->sync, true, false,
-				GET_SEGNO(sbi, range->start));
+	gc_control.victim_segno = GET_SEGNO(sbi, range->start);
+	ret = f2fs_gc(sbi, &gc_control);
 	if (ret) {
 		if (ret == -EBUSY)
 			ret = -EAGAIN;
@@ -2820,6 +2834,10 @@ static int f2fs_ioc_flush_device(struct file *filp, unsigned long arg)
 	unsigned int start_segno = 0, end_segno = 0;
 	unsigned int dev_start_segno = 0, dev_end_segno = 0;
 	struct f2fs_flush_device range;
+	struct f2fs_gc_control gc_control = {
+			.init_gc_type = FG_GC,
+			.should_migrate_blocks = true,
+			.err_gc_skipped = true };
 	int ret;
 
 	if (!capable(CAP_SYS_ADMIN))
@@ -2863,7 +2881,9 @@ static int f2fs_ioc_flush_device(struct file *filp, unsigned long arg)
 		sm->last_victim[GC_CB] = end_segno + 1;
 		sm->last_victim[GC_GREEDY] = end_segno + 1;
 		sm->last_victim[ALLOC_NEXT] = end_segno + 1;
-		ret = f2fs_gc(sbi, true, true, true, start_segno);
+
+		gc_control.victim_segno = start_segno;
+		ret = f2fs_gc(sbi, &gc_control);
 		if (ret == -EAGAIN)
 			ret = 0;
 		else if (ret < 0)
diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
index ba8e93e517be..f3d58d154240 100644
--- a/fs/f2fs/gc.c
+++ b/fs/f2fs/gc.c
@@ -35,6 +35,9 @@ static int gc_thread_func(void *data)
 	wait_queue_head_t *wq = &sbi->gc_thread->gc_wait_queue_head;
 	wait_queue_head_t *fggc_wq = &sbi->gc_thread->fggc_wq;
 	unsigned int wait_ms;
+	struct f2fs_gc_control gc_control = {
+		.victim_segno = NULL_SEGNO,
+		.should_migrate_blocks = false };
 
 	wait_ms = gc_th->min_sleep_time;
 
@@ -141,8 +144,12 @@ static int gc_thread_func(void *data)
 		if (foreground)
 			sync_mode = false;
 
+		gc_control.init_gc_type = sync_mode ? FG_GC : BG_GC;
+		gc_control.no_bg_gc = foreground;
+		gc_control.err_gc_skipped = sync_mode;
+
 		/* if return value is not zero, no victim was selected */
-		if (f2fs_gc(sbi, sync_mode, !foreground, false, NULL_SEGNO))
+		if (f2fs_gc(sbi, &gc_control))
 			wait_ms = gc_th->no_gc_sleep_time;
 
 		if (foreground)
@@ -1740,21 +1747,20 @@ static int do_garbage_collect(struct f2fs_sb_info *sbi,
 	return seg_freed;
 }
 
-int f2fs_gc(struct f2fs_sb_info *sbi, bool sync,
-			bool background, bool force, unsigned int segno)
+int f2fs_gc(struct f2fs_sb_info *sbi, struct f2fs_gc_control *gc_control)
 {
-	int gc_type = sync ? FG_GC : BG_GC;
+	int gc_type = gc_control->init_gc_type;
+	unsigned int segno = gc_control->victim_segno;
 	int sec_freed = 0, seg_freed = 0, total_freed = 0;
 	int ret = 0;
 	struct cp_control cpc;
-	unsigned int init_segno = segno;
 	struct gc_inode_list gc_list = {
 		.ilist = LIST_HEAD_INIT(gc_list.ilist),
 		.iroot = RADIX_TREE_INIT(gc_list.iroot, GFP_NOFS),
 	};
 	unsigned int skipped_round = 0, round = 0;
 
-	trace_f2fs_gc_begin(sbi->sb, sync, background,
+	trace_f2fs_gc_begin(sbi->sb, gc_type, gc_control->no_bg_gc,
 				get_pages(sbi, F2FS_DIRTY_NODES),
 				get_pages(sbi, F2FS_DIRTY_DENTS),
 				get_pages(sbi, F2FS_DIRTY_IMETA),
@@ -1781,8 +1787,7 @@ int f2fs_gc(struct f2fs_sb_info *sbi, bool sync,
 		 * threshold, we can make them free by checkpoint. Then, we
 		 * secure free segments which doesn't need fggc any more.
 		 */
-		if (prefree_segments(sbi) &&
-				!is_sbi_flag_set(sbi, SBI_CP_DISABLED)) {
+		if (prefree_segments(sbi)) {
 			ret = f2fs_write_checkpoint(sbi, &cpc);
 			if (ret)
 				goto stop;
@@ -1792,7 +1797,7 @@ int f2fs_gc(struct f2fs_sb_info *sbi, bool sync,
 	}
 
 	/* f2fs_balance_fs doesn't need to do BG_GC in critical path. */
-	if (gc_type == BG_GC && !background) {
+	if (gc_type == BG_GC && gc_control->no_bg_gc) {
 		ret = -EINVAL;
 		goto stop;
 	}
@@ -1808,45 +1813,48 @@ int f2fs_gc(struct f2fs_sb_info *sbi, bool sync,
 		goto stop;
 	}
 
-	seg_freed = do_garbage_collect(sbi, segno, &gc_list, gc_type, force);
-	if (gc_type == FG_GC &&
-		seg_freed == f2fs_usable_segs_in_sec(sbi, segno))
-		sec_freed++;
+	seg_freed = do_garbage_collect(sbi, segno, &gc_list, gc_type,
+				gc_control->should_migrate_blocks);
 	total_freed += seg_freed;
 
-	if (gc_type == FG_GC) {
-		if (sbi->skipped_gc_rwsem)
-			skipped_round++;
-		round++;
-	}
+	if (seg_freed == f2fs_usable_segs_in_sec(sbi, segno))
+		sec_freed++;
 
 	if (gc_type == FG_GC)
 		sbi->cur_victim_sec = NULL_SEGNO;
 
-	if (sync)
+	if (gc_control->init_gc_type == FG_GC)
 		goto stop;
 
-	if (!has_not_enough_free_secs(sbi, sec_freed, 0))
+	if (!has_not_enough_free_secs(sbi,
+			(gc_type == FG_GC) ? sec_freed : 0, 0))
 		goto stop;
 
-	if (skipped_round <= MAX_SKIP_GC_COUNT || skipped_round * 2 < round) {
-
-		/* Write checkpoint to reclaim prefree segments */
-		if (free_sections(sbi) < NR_CURSEG_PERSIST_TYPE &&
-				prefree_segments(sbi) &&
-				!is_sbi_flag_set(sbi, SBI_CP_DISABLED)) {
+	/* FG_GC stops GC by skip_count */
+	if (gc_type == FG_GC) {
+		if (sbi->skipped_gc_rwsem)
+			skipped_round++;
+		round++;
+		if (skipped_round > MAX_SKIP_GC_COUNT &&
+				skipped_round * 2 >= round) {
 			ret = f2fs_write_checkpoint(sbi, &cpc);
-			if (ret)
-				goto stop;
+			goto stop;
 		}
-		segno = NULL_SEGNO;
-		goto gc_more;
 	}
-	if (gc_type == FG_GC && !is_sbi_flag_set(sbi, SBI_CP_DISABLED))
+
+	/* Write checkpoint to reclaim prefree segments */
+	if (free_sections(sbi) < NR_CURSEG_PERSIST_TYPE &&
+				prefree_segments(sbi)) {
 		ret = f2fs_write_checkpoint(sbi, &cpc);
+		if (ret)
+			goto stop;
+	}
+	segno = NULL_SEGNO;
+	goto gc_more;
+
 stop:
 	SIT_I(sbi)->last_victim[ALLOC_NEXT] = 0;
-	SIT_I(sbi)->last_victim[FLUSH_DEVICE] = init_segno;
+	SIT_I(sbi)->last_victim[FLUSH_DEVICE] = gc_control->victim_segno;
 
 	if (gc_type == FG_GC)
 		f2fs_unpin_all_sections(sbi, true);
@@ -1864,7 +1872,7 @@ int f2fs_gc(struct f2fs_sb_info *sbi, bool sync,
 
 	put_gc_inode(&gc_list);
 
-	if (sync && !ret)
+	if (gc_control->err_gc_skipped && !ret)
 		ret = sec_freed ? 0 : -EAGAIN;
 	return ret;
 }
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 47934995e2ca..8b4f2b1d2cca 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -399,8 +399,14 @@ void f2fs_balance_fs(struct f2fs_sb_info *sbi, bool need)
 			io_schedule();
 			finish_wait(&sbi->gc_thread->fggc_wq, &wait);
 		} else {
+			struct f2fs_gc_control gc_control = {
+				.victim_segno = NULL_SEGNO,
+				.init_gc_type = BG_GC,
+				.no_bg_gc = true,
+				.should_migrate_blocks = false,
+				.err_gc_skipped = false };
 			f2fs_down_write(&sbi->gc_lock);
-			f2fs_gc(sbi, false, false, false, NULL_SEGNO);
+			f2fs_gc(sbi, &gc_control);
 		}
 	}
 }
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 8c81dd324297..a28c27eed6d0 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -2076,8 +2076,14 @@ static int f2fs_disable_checkpoint(struct f2fs_sb_info *sbi)
 	sbi->gc_mode = GC_URGENT_HIGH;
 
 	while (!f2fs_time_over(sbi, DISABLE_TIME)) {
+		struct f2fs_gc_control gc_control = {
+			.victim_segno = NULL_SEGNO,
+			.init_gc_type = FG_GC,
+			.should_migrate_blocks = false,
+			.err_gc_skipped = true };
+
 		f2fs_down_write(&sbi->gc_lock);
-		err = f2fs_gc(sbi, true, false, false, NULL_SEGNO);
+		err = f2fs_gc(sbi, &gc_control);
 		if (err == -ENODATA) {
 			err = 0;
 			break;
diff --git a/include/trace/events/f2fs.h b/include/trace/events/f2fs.h
index 7e915dbf3674..54ec9e543f09 100644
--- a/include/trace/events/f2fs.h
+++ b/include/trace/events/f2fs.h
@@ -644,19 +644,19 @@ TRACE_EVENT(f2fs_background_gc,
 
 TRACE_EVENT(f2fs_gc_begin,
 
-	TP_PROTO(struct super_block *sb, bool sync, bool background,
+	TP_PROTO(struct super_block *sb, int gc_type, bool no_bg_gc,
 			long long dirty_nodes, long long dirty_dents,
 			long long dirty_imeta, unsigned int free_sec,
 			unsigned int free_seg, int reserved_seg,
 			unsigned int prefree_seg),
 
-	TP_ARGS(sb, sync, background, dirty_nodes, dirty_dents, dirty_imeta,
+	TP_ARGS(sb, gc_type, no_bg_gc, dirty_nodes, dirty_dents, dirty_imeta,
 		free_sec, free_seg, reserved_seg, prefree_seg),
 
 	TP_STRUCT__entry(
 		__field(dev_t,		dev)
-		__field(bool,		sync)
-		__field(bool,		background)
+		__field(int,		gc_type)
+		__field(bool,		no_bg_gc)
 		__field(long long,	dirty_nodes)
 		__field(long long,	dirty_dents)
 		__field(long long,	dirty_imeta)
@@ -668,8 +668,8 @@ TRACE_EVENT(f2fs_gc_begin,
 
 	TP_fast_assign(
 		__entry->dev		= sb->s_dev;
-		__entry->sync		= sync;
-		__entry->background	= background;
+		__entry->gc_type	= gc_type;
+		__entry->no_bg_gc	= no_bg_gc;
 		__entry->dirty_nodes	= dirty_nodes;
 		__entry->dirty_dents	= dirty_dents;
 		__entry->dirty_imeta	= dirty_imeta;
@@ -679,12 +679,12 @@ TRACE_EVENT(f2fs_gc_begin,
 		__entry->prefree_seg	= prefree_seg;
 	),
 
-	TP_printk("dev = (%d,%d), sync = %d, background = %d, nodes = %lld, "
+	TP_printk("dev = (%d,%d), gc_type = %s, no_background_GC = %d, nodes = %lld, "
 		"dents = %lld, imeta = %lld, free_sec:%u, free_seg:%u, "
 		"rsv_seg:%d, prefree_seg:%u",
 		show_dev(__entry->dev),
-		__entry->sync,
-		__entry->background,
+		show_gc_type(__entry->gc_type),
+		(__entry->gc_type == BG_GC) ? __entry->no_bg_gc : -1,
 		__entry->dirty_nodes,
 		__entry->dirty_dents,
 		__entry->dirty_imeta,
-- 
2.36.0.550.gb090851708-goog

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