From ee4cdf7ba857a894ad1650d6ab77669cbbfa329e Mon Sep 17 00:00:00 2001 From: David Howells Date: Tue, 2 Jul 2024 00:40:22 +0100 Subject: netfs: Speed up buffered reading Improve the efficiency of buffered reads in a number of ways: (1) Overhaul the algorithm in general so that it's a lot more compact and split the read submission code between buffered and unbuffered versions. The unbuffered version can be vastly simplified. (2) Read-result collection is handed off to a work queue rather than being done in the I/O thread. Multiple subrequests can be processes simultaneously. (3) When a subrequest is collected, any folios it fully spans are collected and "spare" data on either side is donated to either the previous or the next subrequest in the sequence. Notes: (*) Readahead expansion is massively slows down fio, presumably because it causes a load of extra allocations, both folio and xarray, up front before RPC requests can be transmitted. (*) RDMA with cifs does appear to work, both with SIW and RXE. (*) PG_private_2-based reading and copy-to-cache is split out into its own file and altered to use folio_queue. Note that the copy to the cache now creates a new write transaction against the cache and adds the folios to be copied into it. This allows it to use part of the writeback I/O code. Signed-off-by: David Howells cc: Jeff Layton cc: netfs@lists.linux.dev cc: linux-fsdevel@vger.kernel.org Link: https://lore.kernel.org/r/20240814203850.2240469-20-dhowells@redhat.com/ # v2 Signed-off-by: Christian Brauner --- fs/netfs/internal.h | 35 ++++++++++++++++++++++++++++------- 1 file changed, 28 insertions(+), 7 deletions(-) (limited to 'fs/netfs/internal.h') diff --git a/fs/netfs/internal.h b/fs/netfs/internal.h index 21a3c7d13585..c9f0ed24cb7b 100644 --- a/fs/netfs/internal.h +++ b/fs/netfs/internal.h @@ -23,16 +23,9 @@ /* * buffered_read.c */ -void netfs_rreq_unlock_folios(struct netfs_io_request *rreq); int netfs_prefetch_for_write(struct file *file, struct folio *folio, size_t offset, size_t len); -/* - * io.c - */ -void netfs_rreq_work(struct work_struct *work); -int netfs_begin_read(struct netfs_io_request *rreq, bool sync); - /* * main.c */ @@ -90,6 +83,28 @@ static inline void netfs_see_request(struct netfs_io_request *rreq, trace_netfs_rreq_ref(rreq->debug_id, refcount_read(&rreq->ref), what); } +/* + * read_collect.c + */ +void netfs_read_termination_worker(struct work_struct *work); +void netfs_rreq_terminated(struct netfs_io_request *rreq, bool was_async); + +/* + * read_pgpriv2.c + */ +void netfs_pgpriv2_mark_copy_to_cache(struct netfs_io_subrequest *subreq, + struct netfs_io_request *rreq, + struct folio_queue *folioq, + int slot); +void netfs_pgpriv2_write_to_the_cache(struct netfs_io_request *rreq); +bool netfs_pgpriv2_unlock_copied_folios(struct netfs_io_request *wreq); + +/* + * read_retry.c + */ +void netfs_retry_reads(struct netfs_io_request *rreq); +void netfs_unlock_abandoned_read_pages(struct netfs_io_request *rreq); + /* * stats.c */ @@ -117,6 +132,7 @@ extern atomic_t netfs_n_wh_buffered_write; extern atomic_t netfs_n_wh_writethrough; extern atomic_t netfs_n_wh_dio_write; extern atomic_t netfs_n_wh_writepages; +extern atomic_t netfs_n_wh_copy_to_cache; extern atomic_t netfs_n_wh_wstream_conflict; extern atomic_t netfs_n_wh_upload; extern atomic_t netfs_n_wh_upload_done; @@ -162,6 +178,11 @@ struct netfs_io_request *netfs_create_write_req(struct address_space *mapping, void netfs_reissue_write(struct netfs_io_stream *stream, struct netfs_io_subrequest *subreq, struct iov_iter *source); +void netfs_issue_write(struct netfs_io_request *wreq, + struct netfs_io_stream *stream); +int netfs_advance_write(struct netfs_io_request *wreq, + struct netfs_io_stream *stream, + loff_t start, size_t len, bool to_eof); struct netfs_io_request *netfs_begin_writethrough(struct kiocb *iocb, size_t len); int netfs_advance_writethrough(struct netfs_io_request *wreq, struct writeback_control *wbc, struct folio *folio, size_t copied, bool to_page_end, -- cgit