David Howells d9f85a04fb netfs: Use mempools for allocating requests and subrequests
Use mempools for allocating requests and subrequests in an effort to make
sure that allocation always succeeds so that when performing writeback we
can always make progress.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
cc: linux-mm@kvack.org
2024-05-01 18:07:35 +01:00

169 lines
4.3 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/* Miscellaneous bits for the netfs support library.
*
* Copyright (C) 2022 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*/
#include <linux/module.h>
#include <linux/export.h>
#include <linux/mempool.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include "internal.h"
#define CREATE_TRACE_POINTS
#include <trace/events/netfs.h>
MODULE_DESCRIPTION("Network fs support");
MODULE_AUTHOR("Red Hat, Inc.");
MODULE_LICENSE("GPL");
EXPORT_TRACEPOINT_SYMBOL(netfs_sreq);
unsigned netfs_debug;
module_param_named(debug, netfs_debug, uint, S_IWUSR | S_IRUGO);
MODULE_PARM_DESC(netfs_debug, "Netfs support debugging mask");
static struct kmem_cache *netfs_request_slab;
static struct kmem_cache *netfs_subrequest_slab;
mempool_t netfs_request_pool;
mempool_t netfs_subrequest_pool;
#ifdef CONFIG_PROC_FS
LIST_HEAD(netfs_io_requests);
DEFINE_SPINLOCK(netfs_proc_lock);
static const char *netfs_origins[nr__netfs_io_origin] = {
[NETFS_READAHEAD] = "RA",
[NETFS_READPAGE] = "RP",
[NETFS_READ_FOR_WRITE] = "RW",
[NETFS_COPY_TO_CACHE] = "CC",
[NETFS_WRITEBACK] = "WB",
[NETFS_WRITETHROUGH] = "WT",
[NETFS_UNBUFFERED_WRITE] = "UW",
[NETFS_DIO_READ] = "DR",
[NETFS_DIO_WRITE] = "DW",
};
/*
* Generate a list of I/O requests in /proc/fs/netfs/requests
*/
static int netfs_requests_seq_show(struct seq_file *m, void *v)
{
struct netfs_io_request *rreq;
if (v == &netfs_io_requests) {
seq_puts(m,
"REQUEST OR REF FL ERR OPS COVERAGE\n"
"======== == === == ==== === =========\n"
);
return 0;
}
rreq = list_entry(v, struct netfs_io_request, proc_link);
seq_printf(m,
"%08x %s %3d %2lx %4d %3d @%04llx %zx/%zx",
rreq->debug_id,
netfs_origins[rreq->origin],
refcount_read(&rreq->ref),
rreq->flags,
rreq->error,
atomic_read(&rreq->nr_outstanding),
rreq->start, rreq->submitted, rreq->len);
seq_putc(m, '\n');
return 0;
}
static void *netfs_requests_seq_start(struct seq_file *m, loff_t *_pos)
__acquires(rcu)
{
rcu_read_lock();
return seq_list_start_head(&netfs_io_requests, *_pos);
}
static void *netfs_requests_seq_next(struct seq_file *m, void *v, loff_t *_pos)
{
return seq_list_next(v, &netfs_io_requests, _pos);
}
static void netfs_requests_seq_stop(struct seq_file *m, void *v)
__releases(rcu)
{
rcu_read_unlock();
}
static const struct seq_operations netfs_requests_seq_ops = {
.start = netfs_requests_seq_start,
.next = netfs_requests_seq_next,
.stop = netfs_requests_seq_stop,
.show = netfs_requests_seq_show,
};
#endif /* CONFIG_PROC_FS */
static int __init netfs_init(void)
{
int ret = -ENOMEM;
netfs_request_slab = kmem_cache_create("netfs_request",
sizeof(struct netfs_io_request), 0,
SLAB_HWCACHE_ALIGN | SLAB_ACCOUNT,
NULL);
if (!netfs_request_slab)
goto error_req;
if (mempool_init_slab_pool(&netfs_request_pool, 100, netfs_request_slab) < 0)
goto error_reqpool;
netfs_subrequest_slab = kmem_cache_create("netfs_subrequest",
sizeof(struct netfs_io_subrequest), 0,
SLAB_HWCACHE_ALIGN | SLAB_ACCOUNT,
NULL);
if (!netfs_subrequest_slab)
goto error_subreq;
if (mempool_init_slab_pool(&netfs_subrequest_pool, 100, netfs_subrequest_slab) < 0)
goto error_subreqpool;
if (!proc_mkdir("fs/netfs", NULL))
goto error_proc;
if (!proc_create_seq("fs/netfs/requests", S_IFREG | 0444, NULL,
&netfs_requests_seq_ops))
goto error_procfile;
#ifdef CONFIG_FSCACHE_STATS
if (!proc_create_single("fs/netfs/stats", S_IFREG | 0444, NULL,
netfs_stats_show))
goto error_procfile;
#endif
ret = fscache_init();
if (ret < 0)
goto error_fscache;
return 0;
error_fscache:
error_procfile:
remove_proc_entry("fs/netfs", NULL);
error_proc:
mempool_exit(&netfs_subrequest_pool);
error_subreqpool:
kmem_cache_destroy(netfs_subrequest_slab);
error_subreq:
mempool_exit(&netfs_request_pool);
error_reqpool:
kmem_cache_destroy(netfs_request_slab);
error_req:
return ret;
}
fs_initcall(netfs_init);
static void __exit netfs_exit(void)
{
fscache_exit();
remove_proc_entry("fs/netfs", NULL);
mempool_exit(&netfs_subrequest_pool);
kmem_cache_destroy(netfs_subrequest_slab);
mempool_exit(&netfs_request_pool);
kmem_cache_destroy(netfs_request_slab);
}
module_exit(netfs_exit);