mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2024-11-15 00:04:15 +08:00
ee4cdf7ba8
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>
202 lines
6.5 KiB
C
202 lines
6.5 KiB
C
/* SPDX-License-Identifier: GPL-2.0-or-later */
|
|
/* NFS filesystem cache interface definitions
|
|
*
|
|
* Copyright (C) 2008 Red Hat, Inc. All Rights Reserved.
|
|
* Written by David Howells (dhowells@redhat.com)
|
|
*/
|
|
|
|
#ifndef _NFS_FSCACHE_H
|
|
#define _NFS_FSCACHE_H
|
|
|
|
#include <linux/swap.h>
|
|
#include <linux/nfs_fs.h>
|
|
#include <linux/nfs_mount.h>
|
|
#include <linux/nfs4_mount.h>
|
|
#include <linux/fscache.h>
|
|
#include <linux/iversion.h>
|
|
|
|
#ifdef CONFIG_NFS_FSCACHE
|
|
|
|
/*
|
|
* Definition of the auxiliary data attached to NFS inode storage objects
|
|
* within the cache.
|
|
*
|
|
* The contents of this struct are recorded in the on-disk local cache in the
|
|
* auxiliary data attached to the data storage object backing an inode. This
|
|
* permits coherency to be managed when a new inode binds to an already extant
|
|
* cache object.
|
|
*/
|
|
struct nfs_fscache_inode_auxdata {
|
|
s64 mtime_sec;
|
|
s64 mtime_nsec;
|
|
s64 ctime_sec;
|
|
s64 ctime_nsec;
|
|
u64 change_attr;
|
|
};
|
|
|
|
struct nfs_netfs_io_data {
|
|
/*
|
|
* NFS may split a netfs_io_subrequest into multiple RPCs, each
|
|
* with their own read completion. In netfs, we can only call
|
|
* netfs_subreq_terminated() once for each subrequest. Use the
|
|
* refcount here to double as a marker of the last RPC completion,
|
|
* and only call netfs via netfs_subreq_terminated() once.
|
|
*/
|
|
refcount_t refcount;
|
|
struct netfs_io_subrequest *sreq;
|
|
|
|
/*
|
|
* Final disposition of the netfs_io_subrequest, sent in
|
|
* netfs_subreq_terminated()
|
|
*/
|
|
atomic64_t transferred;
|
|
int error;
|
|
};
|
|
|
|
static inline void nfs_netfs_get(struct nfs_netfs_io_data *netfs)
|
|
{
|
|
refcount_inc(&netfs->refcount);
|
|
}
|
|
|
|
static inline void nfs_netfs_put(struct nfs_netfs_io_data *netfs)
|
|
{
|
|
/* Only the last RPC completion should call netfs_subreq_terminated() */
|
|
if (!refcount_dec_and_test(&netfs->refcount))
|
|
return;
|
|
|
|
/*
|
|
* The NFS pageio interface may read a complete page, even when netfs
|
|
* only asked for a partial page. Specifically, this may be seen when
|
|
* one thread is truncating a file while another one is reading the last
|
|
* page of the file.
|
|
* Correct the final length here to be no larger than the netfs subrequest
|
|
* length, and thus avoid netfs's "Subreq overread" warning message.
|
|
*/
|
|
netfs->sreq->transferred = min_t(s64, netfs->sreq->len,
|
|
atomic64_read(&netfs->transferred));
|
|
netfs_read_subreq_terminated(netfs->sreq, netfs->error, false);
|
|
kfree(netfs);
|
|
}
|
|
static inline void nfs_netfs_inode_init(struct nfs_inode *nfsi)
|
|
{
|
|
netfs_inode_init(&nfsi->netfs, &nfs_netfs_ops, false);
|
|
}
|
|
extern void nfs_netfs_initiate_read(struct nfs_pgio_header *hdr);
|
|
extern void nfs_netfs_read_completion(struct nfs_pgio_header *hdr);
|
|
extern int nfs_netfs_folio_unlock(struct folio *folio);
|
|
|
|
/*
|
|
* fscache.c
|
|
*/
|
|
extern int nfs_fscache_get_super_cookie(struct super_block *, const char *, int);
|
|
extern void nfs_fscache_release_super_cookie(struct super_block *);
|
|
|
|
extern void nfs_fscache_init_inode(struct inode *);
|
|
extern void nfs_fscache_clear_inode(struct inode *);
|
|
extern void nfs_fscache_open_file(struct inode *, struct file *);
|
|
extern void nfs_fscache_release_file(struct inode *, struct file *);
|
|
extern int nfs_netfs_readahead(struct readahead_control *ractl);
|
|
extern int nfs_netfs_read_folio(struct file *file, struct folio *folio);
|
|
|
|
static inline bool nfs_fscache_release_folio(struct folio *folio, gfp_t gfp)
|
|
{
|
|
if (folio_test_private_2(folio)) { /* [DEPRECATED] */
|
|
if (current_is_kswapd() || !(gfp & __GFP_FS))
|
|
return false;
|
|
folio_wait_private_2(folio);
|
|
}
|
|
fscache_note_page_release(netfs_i_cookie(netfs_inode(folio->mapping->host)));
|
|
return true;
|
|
}
|
|
|
|
static inline void nfs_fscache_update_auxdata(struct nfs_fscache_inode_auxdata *auxdata,
|
|
struct inode *inode)
|
|
{
|
|
memset(auxdata, 0, sizeof(*auxdata));
|
|
auxdata->mtime_sec = inode_get_mtime(inode).tv_sec;
|
|
auxdata->mtime_nsec = inode_get_mtime(inode).tv_nsec;
|
|
auxdata->ctime_sec = inode_get_ctime(inode).tv_sec;
|
|
auxdata->ctime_nsec = inode_get_ctime(inode).tv_nsec;
|
|
|
|
if (NFS_SERVER(inode)->nfs_client->rpc_ops->version == 4)
|
|
auxdata->change_attr = inode_peek_iversion_raw(inode);
|
|
}
|
|
|
|
/*
|
|
* Invalidate the contents of fscache for this inode. This will not sleep.
|
|
*/
|
|
static inline void nfs_fscache_invalidate(struct inode *inode, int flags)
|
|
{
|
|
struct nfs_fscache_inode_auxdata auxdata;
|
|
struct fscache_cookie *cookie = netfs_i_cookie(&NFS_I(inode)->netfs);
|
|
|
|
nfs_fscache_update_auxdata(&auxdata, inode);
|
|
fscache_invalidate(cookie, &auxdata, i_size_read(inode), flags);
|
|
}
|
|
|
|
/*
|
|
* indicate the client caching state as readable text
|
|
*/
|
|
static inline const char *nfs_server_fscache_state(struct nfs_server *server)
|
|
{
|
|
if (server->fscache)
|
|
return "yes";
|
|
return "no ";
|
|
}
|
|
|
|
static inline void nfs_netfs_set_pgio_header(struct nfs_pgio_header *hdr,
|
|
struct nfs_pageio_descriptor *desc)
|
|
{
|
|
hdr->netfs = desc->pg_netfs;
|
|
}
|
|
static inline void nfs_netfs_set_pageio_descriptor(struct nfs_pageio_descriptor *desc,
|
|
struct nfs_pgio_header *hdr)
|
|
{
|
|
desc->pg_netfs = hdr->netfs;
|
|
}
|
|
static inline void nfs_netfs_reset_pageio_descriptor(struct nfs_pageio_descriptor *desc)
|
|
{
|
|
desc->pg_netfs = NULL;
|
|
}
|
|
#else /* CONFIG_NFS_FSCACHE */
|
|
static inline void nfs_netfs_inode_init(struct nfs_inode *nfsi) {}
|
|
static inline void nfs_netfs_initiate_read(struct nfs_pgio_header *hdr) {}
|
|
static inline void nfs_netfs_read_completion(struct nfs_pgio_header *hdr) {}
|
|
static inline int nfs_netfs_folio_unlock(struct folio *folio)
|
|
{
|
|
return 1;
|
|
}
|
|
static inline void nfs_fscache_release_super_cookie(struct super_block *sb) {}
|
|
|
|
static inline void nfs_fscache_init_inode(struct inode *inode) {}
|
|
static inline void nfs_fscache_clear_inode(struct inode *inode) {}
|
|
static inline void nfs_fscache_open_file(struct inode *inode,
|
|
struct file *filp) {}
|
|
static inline void nfs_fscache_release_file(struct inode *inode, struct file *file) {}
|
|
static inline int nfs_netfs_readahead(struct readahead_control *ractl)
|
|
{
|
|
return -ENOBUFS;
|
|
}
|
|
static inline int nfs_netfs_read_folio(struct file *file, struct folio *folio)
|
|
{
|
|
return -ENOBUFS;
|
|
}
|
|
|
|
static inline bool nfs_fscache_release_folio(struct folio *folio, gfp_t gfp)
|
|
{
|
|
return true; /* may release folio */
|
|
}
|
|
static inline void nfs_fscache_invalidate(struct inode *inode, int flags) {}
|
|
|
|
static inline const char *nfs_server_fscache_state(struct nfs_server *server)
|
|
{
|
|
return "no ";
|
|
}
|
|
static inline void nfs_netfs_set_pgio_header(struct nfs_pgio_header *hdr,
|
|
struct nfs_pageio_descriptor *desc) {}
|
|
static inline void nfs_netfs_set_pageio_descriptor(struct nfs_pageio_descriptor *desc,
|
|
struct nfs_pgio_header *hdr) {}
|
|
static inline void nfs_netfs_reset_pageio_descriptor(struct nfs_pageio_descriptor *desc) {}
|
|
#endif /* CONFIG_NFS_FSCACHE */
|
|
#endif /* _NFS_FSCACHE_H */
|