f2fs: clarify and enhance the f2fs_gc flow
This patch makes clearer the ambiguous f2fs_gc flow as follows.
1. Remove intermediate checkpoint condition during f2fs_gc
(i.e., should_do_checkpoint() and GC_BLOCKED)
2. Remove unnecessary return values of f2fs_gc because of #1.
(i.e., GC_NODE, GC_OK, etc)
3. Simplify write_checkpoint() because of #2.
4. Clarify the main f2fs_gc flow.
o monitor how many freed sections during one iteration of do_garbage_collect().
o do GC more without checkpoints if we can't get enough free sections.
o do checkpoint once we've got enough free sections through forground GCs.
5. Adopt thread-logging (Slack-Space-Recycle) scheme more aggressively on data
log types. See. get_ssr_segement()
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 7aa270f..777f17e 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -29,7 +29,7 @@
* We should do GC or end up with checkpoint, if there are so many dirty
* dir/node pages without enough free segments.
*/
- if (has_not_enough_free_secs(sbi)) {
+ if (has_not_enough_free_secs(sbi, 0)) {
mutex_lock(&sbi->gc_mutex);
f2fs_gc(sbi);
}
@@ -308,7 +308,7 @@
* If there is not enough reserved sections,
* we should not reuse prefree segments.
*/
- if (has_not_enough_free_secs(sbi))
+ if (has_not_enough_free_secs(sbi, 0))
return NULL_SEGNO;
/*
@@ -536,6 +536,23 @@
}
}
+static int get_ssr_segment(struct f2fs_sb_info *sbi, int type)
+{
+ struct curseg_info *curseg = CURSEG_I(sbi, type);
+ const struct victim_selection *v_ops = DIRTY_I(sbi)->v_ops;
+
+ if (IS_NODESEG(type) || !has_not_enough_free_secs(sbi, 0))
+ return v_ops->get_victim(sbi,
+ &(curseg)->next_segno, BG_GC, type, SSR);
+
+ /* For data segments, let's do SSR more intensively */
+ for (; type >= CURSEG_HOT_DATA; type--)
+ if (v_ops->get_victim(sbi, &(curseg)->next_segno,
+ BG_GC, type, SSR))
+ return 1;
+ return 0;
+}
+
/*
* flush out current segment and replace it with new segment
* This function should be returned with success, otherwise BUG