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linux/fs/netfs/stats.c
David Howells ee4cdf7ba8
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 <dhowells@redhat.com>
cc: Jeff Layton <jlayton@kernel.org>
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 <brauner@kernel.org>
2024-09-12 12:20:41 +02:00

93 lines
3.2 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/* Netfs support statistics
*
* Copyright (C) 2021 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*/
#include <linux/export.h>
#include <linux/seq_file.h>
#include "internal.h"
atomic_t netfs_n_rh_dio_read;
atomic_t netfs_n_rh_readahead;
atomic_t netfs_n_rh_read_folio;
atomic_t netfs_n_rh_rreq;
atomic_t netfs_n_rh_sreq;
atomic_t netfs_n_rh_download;
atomic_t netfs_n_rh_download_done;
atomic_t netfs_n_rh_download_failed;
atomic_t netfs_n_rh_download_instead;
atomic_t netfs_n_rh_read;
atomic_t netfs_n_rh_read_done;
atomic_t netfs_n_rh_read_failed;
atomic_t netfs_n_rh_zero;
atomic_t netfs_n_rh_short_read;
atomic_t netfs_n_rh_write;
atomic_t netfs_n_rh_write_begin;
atomic_t netfs_n_rh_write_done;
atomic_t netfs_n_rh_write_failed;
atomic_t netfs_n_rh_write_zskip;
atomic_t netfs_n_wh_buffered_write;
atomic_t netfs_n_wh_writethrough;
atomic_t netfs_n_wh_dio_write;
atomic_t netfs_n_wh_writepages;
atomic_t netfs_n_wh_copy_to_cache;
atomic_t netfs_n_wh_wstream_conflict;
atomic_t netfs_n_wh_upload;
atomic_t netfs_n_wh_upload_done;
atomic_t netfs_n_wh_upload_failed;
atomic_t netfs_n_wh_write;
atomic_t netfs_n_wh_write_done;
atomic_t netfs_n_wh_write_failed;
atomic_t netfs_n_wb_lock_skip;
atomic_t netfs_n_wb_lock_wait;
atomic_t netfs_n_folioq;
int netfs_stats_show(struct seq_file *m, void *v)
{
seq_printf(m, "Reads : DR=%u RA=%u RF=%u WB=%u WBZ=%u\n",
atomic_read(&netfs_n_rh_dio_read),
atomic_read(&netfs_n_rh_readahead),
atomic_read(&netfs_n_rh_read_folio),
atomic_read(&netfs_n_rh_write_begin),
atomic_read(&netfs_n_rh_write_zskip));
seq_printf(m, "Writes : BW=%u WT=%u DW=%u WP=%u 2C=%u\n",
atomic_read(&netfs_n_wh_buffered_write),
atomic_read(&netfs_n_wh_writethrough),
atomic_read(&netfs_n_wh_dio_write),
atomic_read(&netfs_n_wh_writepages),
atomic_read(&netfs_n_wh_copy_to_cache));
seq_printf(m, "ZeroOps: ZR=%u sh=%u sk=%u\n",
atomic_read(&netfs_n_rh_zero),
atomic_read(&netfs_n_rh_short_read),
atomic_read(&netfs_n_rh_write_zskip));
seq_printf(m, "DownOps: DL=%u ds=%u df=%u di=%u\n",
atomic_read(&netfs_n_rh_download),
atomic_read(&netfs_n_rh_download_done),
atomic_read(&netfs_n_rh_download_failed),
atomic_read(&netfs_n_rh_download_instead));
seq_printf(m, "CaRdOps: RD=%u rs=%u rf=%u\n",
atomic_read(&netfs_n_rh_read),
atomic_read(&netfs_n_rh_read_done),
atomic_read(&netfs_n_rh_read_failed));
seq_printf(m, "UpldOps: UL=%u us=%u uf=%u\n",
atomic_read(&netfs_n_wh_upload),
atomic_read(&netfs_n_wh_upload_done),
atomic_read(&netfs_n_wh_upload_failed));
seq_printf(m, "CaWrOps: WR=%u ws=%u wf=%u\n",
atomic_read(&netfs_n_wh_write),
atomic_read(&netfs_n_wh_write_done),
atomic_read(&netfs_n_wh_write_failed));
seq_printf(m, "Objs : rr=%u sr=%u foq=%u wsc=%u\n",
atomic_read(&netfs_n_rh_rreq),
atomic_read(&netfs_n_rh_sreq),
atomic_read(&netfs_n_folioq),
atomic_read(&netfs_n_wh_wstream_conflict));
seq_printf(m, "WbLock : skip=%u wait=%u\n",
atomic_read(&netfs_n_wb_lock_skip),
atomic_read(&netfs_n_wb_lock_wait));
return fscache_stats_show(m);
}
EXPORT_SYMBOL(netfs_stats_show);