diff options
| author | Kent Overstreet <kent.overstreet@linux.dev> | 2024-10-14 21:35:44 -0400 |
|---|---|---|
| committer | Kent Overstreet <kent.overstreet@linux.dev> | 2024-12-21 01:36:15 -0500 |
| commit | 27de0ee39f810dab2e948d2c465f8fcf8cbf9f8c (patch) | |
| tree | 5125cee5e3e2ecdff6feb3c71f6eb1e0df4c62f9 | |
| parent | be5a7be1062b2e588519d7ed68ff2e8f4ed0a42a (diff) | |
bcachefs: Add block plugging to read paths
This will help with some of the btree_trans srcu lock hold time warnings
that are still turning up; submit_bio() can block for awhile if the
device is sufficiently congested.
It's not a perfect solution since blk_plug bios are submitted when
scheduling; we might want a way to disable the "submit on context
switch" behaviour, or switch to our own plugging in the future.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
| -rw-r--r-- | fs/bcachefs/fs-io-buffered.c | 19 | ||||
| -rw-r--r-- | fs/bcachefs/fs-io-direct.c | 5 |
2 files changed, 23 insertions, 1 deletions
diff --git a/fs/bcachefs/fs-io-buffered.c b/fs/bcachefs/fs-io-buffered.c index 95972809e76d..0923f38a2fcd 100644 --- a/fs/bcachefs/fs-io-buffered.c +++ b/fs/bcachefs/fs-io-buffered.c @@ -248,6 +248,7 @@ void bch2_readahead(struct readahead_control *ractl) struct bch_io_opts opts; struct folio *folio; struct readpages_iter readpages_iter; + struct blk_plug plug; bch2_inode_opts_get(&opts, c, &inode->ei_inode); @@ -255,6 +256,16 @@ void bch2_readahead(struct readahead_control *ractl) if (ret) return; + /* + * Besides being a general performance optimization, plugging helps with + * avoiding btree transaction srcu warnings - submitting a bio can + * block, and we don't want todo that with the transaction locked. + * + * However, plugged bios are submitted when we schedule; we ideally + * would have our own scheduler hook to call unlock_long() before + * scheduling. + */ + blk_start_plug(&plug); bch2_pagecache_add_get(inode); struct btree_trans *trans = bch2_trans_get(c); @@ -281,7 +292,7 @@ void bch2_readahead(struct readahead_control *ractl) bch2_trans_put(trans); bch2_pagecache_add_put(inode); - + blk_finish_plug(&plug); darray_exit(&readpages_iter.folios); } @@ -296,9 +307,13 @@ int bch2_read_single_folio(struct folio *folio, struct address_space *mapping) struct bch_fs *c = inode->v.i_sb->s_fs_info; struct bch_read_bio *rbio; struct bch_io_opts opts; + struct blk_plug plug; int ret; DECLARE_COMPLETION_ONSTACK(done); + BUG_ON(folio_test_uptodate(folio)); + BUG_ON(folio_test_dirty(folio)); + if (!bch2_folio_create(folio, GFP_KERNEL)) return -ENOMEM; @@ -313,7 +328,9 @@ int bch2_read_single_folio(struct folio *folio, struct address_space *mapping) rbio->bio.bi_iter.bi_sector = folio_sector(folio); BUG_ON(!bio_add_folio(&rbio->bio, folio, folio_size(folio), 0)); + blk_start_plug(&plug); bch2_trans_run(c, (bchfs_read(trans, rbio, inode_inum(inode), NULL), 0)); + blk_finish_plug(&plug); wait_for_completion(&done); ret = blk_status_to_errno(rbio->bio.bi_status); diff --git a/fs/bcachefs/fs-io-direct.c b/fs/bcachefs/fs-io-direct.c index 6d3a05ae5da8..2089c36b5866 100644 --- a/fs/bcachefs/fs-io-direct.c +++ b/fs/bcachefs/fs-io-direct.c @@ -70,6 +70,7 @@ static int bch2_direct_IO_read(struct kiocb *req, struct iov_iter *iter) struct bch_io_opts opts; struct dio_read *dio; struct bio *bio; + struct blk_plug plug; loff_t offset = req->ki_pos; bool sync = is_sync_kiocb(req); size_t shorten; @@ -128,6 +129,8 @@ static int bch2_direct_IO_read(struct kiocb *req, struct iov_iter *iter) */ dio->should_dirty = iter_is_iovec(iter); + blk_start_plug(&plug); + goto start; while (iter->count) { bio = bio_alloc_bioset(NULL, @@ -160,6 +163,8 @@ start: bch2_read(c, rbio_init(bio, opts), inode_inum(inode)); } + blk_finish_plug(&plug); + iter->count += shorten; if (sync) { |