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bcachefs: BCH_WATERMARK_interior_updates

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This adds a new watermark, higher priority than BCH_WATERMARK_reclaim,
for interior btree updates. We've seen a deadlock where journal replay
triggers a ton of btree node merges, and these use up all available open
buckets and then interior updates get stuck.

One cause of this is that we're currently lacking btree node merging on
write buffer btrees - that needs to be fixed as well.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
This commit is contained in:
Kent Overstreet 2024-04-01 19:20:36 -04:00
parent ba947ecd39
commit e2a316b3cc
6 changed files with 12 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
fs/bcachefs/alloc_foreground.c
View File

@ -188,8 +188,10 @@ long bch2_bucket_alloc_new_fs(struct bch_dev *ca)
static inline unsigned open_buckets_reserved(enum bch_watermark watermark)
{
switch (watermark) {
case BCH_WATERMARK_reclaim:
case BCH_WATERMARK_interior_updates:
return 0;
case BCH_WATERMARK_reclaim:
return OPEN_BUCKETS_COUNT / 6;
case BCH_WATERMARK_btree:
case BCH_WATERMARK_btree_copygc:
return OPEN_BUCKETS_COUNT / 4;

3
fs/bcachefs/alloc_types.h
View File

@ -22,7 +22,8 @@ struct bucket_alloc_state {
x(copygc) \
x(btree) \
x(btree_copygc) \
x(reclaim)
x(reclaim) \
x(interior_updates)
enum bch_watermark {
#define x(name) BCH_WATERMARK_##name,

2
fs/bcachefs/btree_io.c
View File

@ -1861,7 +1861,7 @@ static void btree_node_write_work(struct work_struct *work)
} else {
ret = bch2_trans_do(c, NULL, NULL, 0,
bch2_btree_node_update_key_get_iter(trans, b, &wbio->key,
BCH_WATERMARK_reclaim|
BCH_WATERMARK_interior_updates|
BCH_TRANS_COMMIT_journal_reclaim|
BCH_TRANS_COMMIT_no_enospc|
BCH_TRANS_COMMIT_no_check_rw,

3
fs/bcachefs/btree_trans_commit.c
View File

@ -887,6 +887,7 @@ int bch2_trans_commit_error(struct btree_trans *trans, unsigned flags,
int ret, unsigned long trace_ip)
{
struct bch_fs *c = trans->c;
enum bch_watermark watermark = flags & BCH_WATERMARK_MASK;
switch (ret) {
case -BCH_ERR_btree_insert_btree_node_full:
@ -905,7 +906,7 @@ int bch2_trans_commit_error(struct btree_trans *trans, unsigned flags,
* flag
*/
if ((flags & BCH_TRANS_COMMIT_journal_reclaim) &&
(flags & BCH_WATERMARK_MASK) != BCH_WATERMARK_reclaim) {
watermark < BCH_WATERMARK_reclaim) {
ret = -BCH_ERR_journal_reclaim_would_deadlock;
break;
}

6
fs/bcachefs/btree_update_interior.c
View File

@ -687,7 +687,7 @@ static void btree_update_nodes_written(struct btree_update *as)
* which may require allocations as well.
*/
ret = commit_do(trans, &as->disk_res, &journal_seq,
BCH_WATERMARK_reclaim|
BCH_WATERMARK_interior_updates|
BCH_TRANS_COMMIT_no_enospc|
BCH_TRANS_COMMIT_no_check_rw|
BCH_TRANS_COMMIT_journal_reclaim,
@ -1121,7 +1121,7 @@ bch2_btree_update_start(struct btree_trans *trans, struct btree_path *path,
unsigned journal_flags = watermark|JOURNAL_RES_GET_CHECK;
if ((flags & BCH_TRANS_COMMIT_journal_reclaim) &&
watermark != BCH_WATERMARK_reclaim)
watermark < BCH_WATERMARK_reclaim)
journal_flags |= JOURNAL_RES_GET_NONBLOCK;
ret = drop_locks_do(trans,
@ -1217,7 +1217,7 @@ bch2_btree_update_start(struct btree_trans *trans, struct btree_path *path,
*/
if (bch2_err_matches(ret, ENOSPC) &&
(flags & BCH_TRANS_COMMIT_journal_reclaim) &&
watermark != BCH_WATERMARK_reclaim) {
watermark < BCH_WATERMARK_reclaim) {
ret = -BCH_ERR_journal_reclaim_would_deadlock;
goto err;
}

1
fs/bcachefs/buckets.h
View File

@ -226,6 +226,7 @@ static inline u64 bch2_dev_buckets_reserved(struct bch_dev *ca, enum bch_waterma
fallthrough;
case BCH_WATERMARK_btree_copygc:
case BCH_WATERMARK_reclaim:
case BCH_WATERMARK_interior_updates:
break;
}