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/objects.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) (limited to 'fs/netfs/objects.c') diff --git a/fs/netfs/objects.c b/fs/netfs/objects.c index 4291cd405fc1..31e388ec6e48 100644 --- a/fs/netfs/objects.c +++ b/fs/netfs/objects.c @@ -36,7 +36,6 @@ struct netfs_io_request *netfs_alloc_request(struct address_space *mapping, memset(rreq, 0, kmem_cache_size(cache)); rreq->start = start; rreq->len = len; - rreq->upper_len = len; rreq->origin = origin; rreq->netfs_ops = ctx->ops; rreq->mapping = mapping; @@ -44,6 +43,8 @@ struct netfs_io_request *netfs_alloc_request(struct address_space *mapping, rreq->i_size = i_size_read(inode); rreq->debug_id = atomic_inc_return(&debug_ids); rreq->wsize = INT_MAX; + rreq->io_streams[0].sreq_max_len = ULONG_MAX; + rreq->io_streams[0].sreq_max_segs = 0; spin_lock_init(&rreq->lock); INIT_LIST_HEAD(&rreq->io_streams[0].subrequests); INIT_LIST_HEAD(&rreq->io_streams[1].subrequests); @@ -52,9 +53,10 @@ struct netfs_io_request *netfs_alloc_request(struct address_space *mapping, if (origin == NETFS_READAHEAD || origin == NETFS_READPAGE || + origin == NETFS_READ_GAPS || origin == NETFS_READ_FOR_WRITE || origin == NETFS_DIO_READ) - INIT_WORK(&rreq->work, netfs_rreq_work); + INIT_WORK(&rreq->work, netfs_read_termination_worker); else INIT_WORK(&rreq->work, netfs_write_collection_worker); @@ -163,7 +165,7 @@ void netfs_put_request(struct netfs_io_request *rreq, bool was_async, if (was_async) { rreq->work.func = netfs_free_request; if (!queue_work(system_unbound_wq, &rreq->work)) - BUG(); + WARN_ON(1); } else { netfs_free_request(&rreq->work); } -- cgit v1.2.3