[PATCH] f2fs: relax async discard commands more

From: Jaegeuk Kim
Date: Thu Dec 29 2016 - 17:07:53 EST


This patch relaxes async discard commands to avoid waiting its end_io during
checkpoint.
Instead of waiting them during checkpoint, it will be done when actually reusing
them.

Test on initial partition of nvme drive.

# time fstrim /mnt/test

Before : 6.158s
After : 4.822s

Reviewed-by: Chao Yu <yuchao0@xxxxxxxxxx>
Signed-off-by: Jaegeuk Kim <jaegeuk@xxxxxxxxxx>
---
fs/f2fs/checkpoint.c | 7 ++-----
fs/f2fs/f2fs.h | 4 +++-
fs/f2fs/segment.c | 23 +++++++++++++++++++----
fs/f2fs/super.c | 3 +++
4 files changed, 27 insertions(+), 10 deletions(-)

diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
index f73ee9534d83..1a9ba69a22ba 100644
--- a/fs/f2fs/checkpoint.c
+++ b/fs/f2fs/checkpoint.c
@@ -1254,7 +1254,6 @@ int write_checkpoint(struct f2fs_sb_info *sbi, struct cp_control *cpc)
f2fs_bug_on(sbi, prefree_segments(sbi));
flush_sit_entries(sbi, cpc);
clear_prefree_segments(sbi, cpc);
- f2fs_wait_all_discard_bio(sbi);
unblock_operations(sbi);
goto out;
}
@@ -1273,12 +1272,10 @@ int write_checkpoint(struct f2fs_sb_info *sbi, struct cp_control *cpc)

/* unlock all the fs_lock[] in do_checkpoint() */
err = do_checkpoint(sbi, cpc);
- if (err) {
+ if (err)
release_discard_addrs(sbi);
- } else {
+ else
clear_prefree_segments(sbi, cpc);
- f2fs_wait_all_discard_bio(sbi);
- }

unblock_operations(sbi);
stat_inc_cp_count(sbi->stat_info);
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index bdcfe2a9b532..e0db895fd84c 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -183,6 +183,8 @@ struct discard_entry {

struct bio_entry {
struct list_head list;
+ block_t lstart;
+ block_t len;
struct bio *bio;
struct completion event;
int error;
@@ -2111,7 +2113,7 @@ void destroy_flush_cmd_control(struct f2fs_sb_info *, bool);
void invalidate_blocks(struct f2fs_sb_info *, block_t);
bool is_checkpointed_data(struct f2fs_sb_info *, block_t);
void refresh_sit_entry(struct f2fs_sb_info *, block_t, block_t);
-void f2fs_wait_all_discard_bio(struct f2fs_sb_info *);
+void f2fs_wait_discard_bio(struct f2fs_sb_info *, block_t);
void clear_prefree_segments(struct f2fs_sb_info *, struct cp_control *);
void release_discard_addrs(struct f2fs_sb_info *);
int npages_for_summary_flush(struct f2fs_sb_info *, bool);
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 485b9118b418..672bcdefe836 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -625,20 +625,23 @@ static void locate_dirty_segment(struct f2fs_sb_info *sbi, unsigned int segno)
}

static struct bio_entry *__add_bio_entry(struct f2fs_sb_info *sbi,
- struct bio *bio)
+ struct bio *bio, block_t lstart, block_t len)
{
struct list_head *wait_list = &(SM_I(sbi)->wait_list);
struct bio_entry *be = f2fs_kmem_cache_alloc(bio_entry_slab, GFP_NOFS);

INIT_LIST_HEAD(&be->list);
be->bio = bio;
+ be->lstart = lstart;
+ be->len = len;
init_completion(&be->event);
list_add_tail(&be->list, wait_list);

return be;
}

-void f2fs_wait_all_discard_bio(struct f2fs_sb_info *sbi)
+/* This should be covered by global mutex, &sit_i->sentry_lock */
+void f2fs_wait_discard_bio(struct f2fs_sb_info *sbi, block_t blkaddr)
{
struct list_head *wait_list = &(SM_I(sbi)->wait_list);
struct bio_entry *be, *tmp;
@@ -647,7 +650,15 @@ void f2fs_wait_all_discard_bio(struct f2fs_sb_info *sbi)
struct bio *bio = be->bio;
int err;

- wait_for_completion_io(&be->event);
+ if (!completion_done(&be->event)) {
+ if ((be->lstart <= blkaddr &&
+ blkaddr < be->lstart + be->len) ||
+ blkaddr == NULL_ADDR)
+ wait_for_completion_io(&be->event);
+ else
+ continue;
+ }
+
err = be->error;
if (err == -EOPNOTSUPP)
err = 0;
@@ -675,6 +686,7 @@ static int __f2fs_issue_discard_async(struct f2fs_sb_info *sbi,
struct block_device *bdev, block_t blkstart, block_t blklen)
{
struct bio *bio = NULL;
+ block_t lblkstart = blkstart;
int err;

trace_f2fs_issue_discard(sbi->sb, blkstart, blklen);
@@ -689,7 +701,8 @@ static int __f2fs_issue_discard_async(struct f2fs_sb_info *sbi,
SECTOR_FROM_BLOCK(blklen),
GFP_NOFS, 0, &bio);
if (!err && bio) {
- struct bio_entry *be = __add_bio_entry(sbi, bio);
+ struct bio_entry *be = __add_bio_entry(sbi, bio,
+ lblkstart, blklen);

bio->bi_private = be;
bio->bi_end_io = f2fs_submit_bio_wait_endio;
@@ -1575,6 +1588,8 @@ void allocate_data_block(struct f2fs_sb_info *sbi, struct page *page,

*new_blkaddr = NEXT_FREE_BLKADDR(sbi, curseg);

+ f2fs_wait_discard_bio(sbi, *new_blkaddr);
+
/*
* __add_sum_entry should be resided under the curseg_mutex
* because, this function updates a summary entry in the
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index f3697f97e527..461c29043aec 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -770,6 +770,9 @@ static void f2fs_put_super(struct super_block *sb)
write_checkpoint(sbi, &cpc);
}

+ /* be sure to wait for any on-going discard commands */
+ f2fs_wait_discard_bio(sbi, NULL_ADDR);
+
/* write_checkpoint can update stat informaion */
f2fs_destroy_stats(sbi);

--
2.11.0