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netfs: Use mempools for allocating requests and subrequests

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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
This commit is contained in:
David Howells 2024-03-15 14:37:18 +00:00
parent b4ff7b178b
commit d9f85a04fb
4 changed files with 88 additions and 27 deletions
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2
fs/netfs/internal.h
View File

@ -37,6 +37,8 @@ int netfs_begin_read(struct netfs_io_request *rreq, bool sync);
extern unsigned int netfs_debug;
extern struct list_head netfs_io_requests;
extern spinlock_t netfs_proc_lock;
extern mempool_t netfs_request_pool;
extern mempool_t netfs_subrequest_pool;
#ifdef CONFIG_PROC_FS
static inline void netfs_proc_add_rreq(struct netfs_io_request *rreq)

51
fs/netfs/main.c
View File

@ -7,6 +7,7 @@
#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"
@ -23,6 +24,11 @@ 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);
@ -98,25 +104,54 @@ 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;
goto error_proc;
if (!proc_create_seq("fs/netfs/requests", S_IFREG | 0444, NULL,
&netfs_requests_seq_ops))
goto error_proc;
goto error_procfile;
#ifdef CONFIG_FSCACHE_STATS
if (!proc_create_single("fs/netfs/stats", S_IFREG | 0444, NULL,
netfs_stats_show))
goto error_proc;
goto error_procfile;
#endif
ret = fscache_init();
if (ret < 0)
goto error_proc;
goto error_fscache;
return 0;
error_proc:
error_fscache:
error_procfile:
remove_proc_entry("fs/netfs", NULL);
error:
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);
@ -125,5 +160,9 @@ 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);

57
fs/netfs/objects.c
View File

@ -6,6 +6,8 @@
*/
#include <linux/slab.h>
#include <linux/mempool.h>
#include <linux/delay.h>
#include "internal.h"
/*
@ -20,17 +22,22 @@ struct netfs_io_request *netfs_alloc_request(struct address_space *mapping,
struct inode *inode = file ? file_inode(file) : mapping->host;
struct netfs_inode *ctx = netfs_inode(inode);
struct netfs_io_request *rreq;
mempool_t *mempool = ctx->ops->request_pool ?: &netfs_request_pool;
struct kmem_cache *cache = mempool->pool_data;
bool is_unbuffered = (origin == NETFS_UNBUFFERED_WRITE ||
origin == NETFS_DIO_READ ||
origin == NETFS_DIO_WRITE);
bool cached = !is_unbuffered && netfs_is_cache_enabled(ctx);
int ret;
rreq = kzalloc(ctx->ops->io_request_size ?: sizeof(struct netfs_io_request),
GFP_KERNEL);
if (!rreq)
return ERR_PTR(-ENOMEM);
for (;;) {
rreq = mempool_alloc(mempool, GFP_KERNEL);
if (rreq)
break;
msleep(10);
}
memset(rreq, 0, kmem_cache_size(cache));
rreq->start = start;
rreq->len = len;
rreq->upper_len = len;
@ -56,7 +63,7 @@ struct netfs_io_request *netfs_alloc_request(struct address_space *mapping,
if (rreq->netfs_ops->init_request) {
ret = rreq->netfs_ops->init_request(rreq, file);
if (ret < 0) {
kfree(rreq);
mempool_free(rreq, rreq->netfs_ops->request_pool ?: &netfs_request_pool);
return ERR_PTR(ret);
}
}
@ -88,6 +95,14 @@ void netfs_clear_subrequests(struct netfs_io_request *rreq, bool was_async)
}
}
static void netfs_free_request_rcu(struct rcu_head *rcu)
{
struct netfs_io_request *rreq = container_of(rcu, struct netfs_io_request, rcu);
mempool_free(rreq, rreq->netfs_ops->request_pool ?: &netfs_request_pool);
netfs_stat_d(&netfs_n_rh_rreq);
}
static void netfs_free_request(struct work_struct *work)
{
struct netfs_io_request *rreq =
@ -110,8 +125,7 @@ static void netfs_free_request(struct work_struct *work)
}
kvfree(rreq->direct_bv);
}
kfree_rcu(rreq, rcu);
netfs_stat_d(&netfs_n_rh_rreq);
call_rcu(&rreq->rcu, netfs_free_request_rcu);
}
void netfs_put_request(struct netfs_io_request *rreq, bool was_async,
@ -143,20 +157,25 @@ void netfs_put_request(struct netfs_io_request *rreq, bool was_async,
struct netfs_io_subrequest *netfs_alloc_subrequest(struct netfs_io_request *rreq)
{
struct netfs_io_subrequest *subreq;
mempool_t *mempool = rreq->netfs_ops->subrequest_pool ?: &netfs_subrequest_pool;
struct kmem_cache *cache = mempool->pool_data;
subreq = kzalloc(rreq->netfs_ops->io_subrequest_size ?:
sizeof(struct netfs_io_subrequest),
GFP_KERNEL);
if (subreq) {
INIT_WORK(&subreq->work, NULL);
INIT_LIST_HEAD(&subreq->rreq_link);
refcount_set(&subreq->ref, 2);
subreq->rreq = rreq;
subreq->debug_index = atomic_inc_return(&rreq->subreq_counter);
netfs_get_request(rreq, netfs_rreq_trace_get_subreq);
netfs_stat(&netfs_n_rh_sreq);
for (;;) {
subreq = mempool_alloc(rreq->netfs_ops->subrequest_pool ?: &netfs_subrequest_pool,
GFP_KERNEL);
if (subreq)
break;
msleep(10);
}
memset(subreq, 0, kmem_cache_size(cache));
INIT_WORK(&subreq->work, NULL);
INIT_LIST_HEAD(&subreq->rreq_link);
refcount_set(&subreq->ref, 2);
subreq->rreq = rreq;
subreq->debug_index = atomic_inc_return(&rreq->subreq_counter);
netfs_get_request(rreq, netfs_rreq_trace_get_subreq);
netfs_stat(&netfs_n_rh_sreq);
return subreq;
}
@ -178,7 +197,7 @@ static void netfs_free_subrequest(struct netfs_io_subrequest *subreq,
trace_netfs_sreq(subreq, netfs_sreq_trace_free);
if (rreq->netfs_ops->free_subrequest)
rreq->netfs_ops->free_subrequest(subreq);
kfree(subreq);
mempool_free(subreq, rreq->netfs_ops->subrequest_pool ?: &netfs_subrequest_pool);
netfs_stat_d(&netfs_n_rh_sreq);
netfs_put_request(rreq, was_async, netfs_rreq_trace_put_subreq);
}

5
include/linux/netfs.h
View File

@ -20,6 +20,7 @@
#include <linux/uio.h>
enum netfs_sreq_ref_trace;
typedef struct mempool_s mempool_t;
/**
* folio_start_private_2 - Start an fscache write on a folio. [DEPRECATED]
@ -236,8 +237,8 @@ struct netfs_io_request {
* Operations the network filesystem can/must provide to the helpers.
*/
struct netfs_request_ops {
unsigned int io_request_size; /* Alloc size for netfs_io_request struct */
unsigned int io_subrequest_size; /* Alloc size for netfs_io_subrequest struct */
mempool_t *request_pool;
mempool_t *subrequest_pool;
int (*init_request)(struct netfs_io_request *rreq, struct file *file);
void (*free_request)(struct netfs_io_request *rreq);
void (*free_subrequest)(struct netfs_io_subrequest *rreq);