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nfsd4: drc containerization 

The nfsd duplicate reply cache should not be shared between network
namespaces.

The most straightforward way to fix this is just to move every global in
the code to per-net-namespace memory, so that's what we do.

Still todo: sort out which members of nfsd_stats should be global and
which per-net-namespace.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>
This commit is contained in:
J. Bruce Fields 2019-05-17 09:03:38 -04:00
parent b401170f6d
commit 3ba75830ce
4 changed files with 154 additions and 125 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
fs/nfsd/cache.h
View File

@ -10,6 +10,7 @@
#define NFSCACHE_H
#include <linux/sunrpc/svc.h>
#include "netns.h"
/*
* Representation of a reply cache entry.
@ -77,8 +78,8 @@ enum {
/* Checksum this amount of the request */
#define RC_CSUMLEN (256U)
int nfsd_reply_cache_init(void);
void nfsd_reply_cache_shutdown(void);
int nfsd_reply_cache_init(struct nfsd_net *);
void nfsd_reply_cache_shutdown(struct nfsd_net *);
int nfsd_cache_lookup(struct svc_rqst *);
void nfsd_cache_update(struct svc_rqst *, int, __be32 *);
int nfsd_reply_cache_stats_open(struct inode *, struct file *);

35
fs/nfsd/netns.h
View File

@ -127,6 +127,41 @@ struct nfsd_net {
*/
bool *nfsd_versions;
bool *nfsd4_minorversions;
/*
* Duplicate reply cache
*/
struct nfsd_drc_bucket *drc_hashtbl;
struct kmem_cache *drc_slab;
/* max number of entries allowed in the cache */
unsigned int max_drc_entries;
/* number of significant bits in the hash value */
unsigned int maskbits;
unsigned int drc_hashsize;
/*
* Stats and other tracking of on the duplicate reply cache. All of these and
* the "rc" fields in nfsdstats are protected by the cache_lock
*/
/* total number of entries */
atomic_t num_drc_entries;
/* cache misses due only to checksum comparison failures */
unsigned int payload_misses;
/* amount of memory (in bytes) currently consumed by the DRC */
unsigned int drc_mem_usage;
/* longest hash chain seen */
unsigned int longest_chain;
/* size of cache when we saw the longest hash chain */
unsigned int longest_chain_cachesize;
struct shrinker nfsd_reply_cache_shrinker;
};
/* Simple check to find out if a given net was properly initialized */

225
fs/nfsd/nfscache.c
View File

@ -9,6 +9,7 @@
* Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
*/
#include <linux/sunrpc/svc_xprt.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/sunrpc/addr.h>
@ -35,48 +36,12 @@ struct nfsd_drc_bucket {
spinlock_t cache_lock;
};
static struct nfsd_drc_bucket *drc_hashtbl;
static struct kmem_cache *drc_slab;
/* max number of entries allowed in the cache */
static unsigned int max_drc_entries;
/* number of significant bits in the hash value */
static unsigned int maskbits;
static unsigned int drc_hashsize;
/*
* Stats and other tracking of on the duplicate reply cache. All of these and
* the "rc" fields in nfsdstats are protected by the cache_lock
*/
/* total number of entries */
static atomic_t num_drc_entries;
/* cache misses due only to checksum comparison failures */
static unsigned int payload_misses;
/* amount of memory (in bytes) currently consumed by the DRC */
static unsigned int drc_mem_usage;
/* longest hash chain seen */
static unsigned int longest_chain;
/* size of cache when we saw the longest hash chain */
static unsigned int longest_chain_cachesize;
static int nfsd_cache_append(struct svc_rqst *rqstp, struct kvec *vec);
static unsigned long nfsd_reply_cache_count(struct shrinker *shrink,
struct shrink_control *sc);
static unsigned long nfsd_reply_cache_scan(struct shrinker *shrink,
struct shrink_control *sc);
static struct shrinker nfsd_reply_cache_shrinker = {
.scan_objects = nfsd_reply_cache_scan,
.count_objects = nfsd_reply_cache_count,
.seeks = 1,
};
/*
* Put a cap on the size of the DRC based on the amount of available
* low memory in the machine.
@ -94,6 +59,9 @@ static struct shrinker nfsd_reply_cache_shrinker = {
* ...with a hard cap of 256k entries. In the worst case, each entry will be
* ~1k, so the above numbers should give a rough max of the amount of memory
* used in k.
*
* XXX: these limits are per-container, so memory used will increase
* linearly with number of containers. Maybe that's OK.
*/
static unsigned int
nfsd_cache_size_limit(void)
@ -116,17 +84,18 @@ nfsd_hashsize(unsigned int limit)
}
static u32
nfsd_cache_hash(__be32 xid)
nfsd_cache_hash(__be32 xid, struct nfsd_net *nn)
{
return hash_32(be32_to_cpu(xid), maskbits);
return hash_32(be32_to_cpu(xid), nn->maskbits);
}
static struct svc_cacherep *
nfsd_reply_cache_alloc(struct svc_rqst *rqstp, __wsum csum)
nfsd_reply_cache_alloc(struct svc_rqst *rqstp, __wsum csum,
struct nfsd_net *nn)
{
struct svc_cacherep *rp;
rp = kmem_cache_alloc(drc_slab, GFP_KERNEL);
rp = kmem_cache_alloc(nn->drc_slab, GFP_KERNEL);
if (rp) {
rp->c_state = RC_UNUSED;
rp->c_type = RC_NOCACHE;
@ -147,62 +116,68 @@ nfsd_reply_cache_alloc(struct svc_rqst *rqstp, __wsum csum)
}
static void
nfsd_reply_cache_free_locked(struct nfsd_drc_bucket *b, struct svc_cacherep *rp)
nfsd_reply_cache_free_locked(struct nfsd_drc_bucket *b, struct svc_cacherep *rp,
struct nfsd_net *nn)
{
if (rp->c_type == RC_REPLBUFF && rp->c_replvec.iov_base) {
drc_mem_usage -= rp->c_replvec.iov_len;
nn->drc_mem_usage -= rp->c_replvec.iov_len;
kfree(rp->c_replvec.iov_base);
}
if (rp->c_state != RC_UNUSED) {
rb_erase(&rp->c_node, &b->rb_head);
list_del(&rp->c_lru);
atomic_dec(&num_drc_entries);
drc_mem_usage -= sizeof(*rp);
atomic_dec(&nn->num_drc_entries);
nn->drc_mem_usage -= sizeof(*rp);
}
kmem_cache_free(drc_slab, rp);
kmem_cache_free(nn->drc_slab, rp);
}
static void
nfsd_reply_cache_free(struct nfsd_drc_bucket *b, struct svc_cacherep *rp)
nfsd_reply_cache_free(struct nfsd_drc_bucket *b, struct svc_cacherep *rp,
struct nfsd_net *nn)
{
spin_lock(&b->cache_lock);
nfsd_reply_cache_free_locked(b, rp);
nfsd_reply_cache_free_locked(b, rp, nn);
spin_unlock(&b->cache_lock);
}
int nfsd_reply_cache_init(void)
int nfsd_reply_cache_init(struct nfsd_net *nn)
{
unsigned int hashsize;
unsigned int i;
int status = 0;
max_drc_entries = nfsd_cache_size_limit();
atomic_set(&num_drc_entries, 0);
hashsize = nfsd_hashsize(max_drc_entries);
maskbits = ilog2(hashsize);
nn->max_drc_entries = nfsd_cache_size_limit();
atomic_set(&nn->num_drc_entries, 0);
hashsize = nfsd_hashsize(nn->max_drc_entries);
nn->maskbits = ilog2(hashsize);
status = register_shrinker(&nfsd_reply_cache_shrinker);
nn->nfsd_reply_cache_shrinker.scan_objects = nfsd_reply_cache_scan;
nn->nfsd_reply_cache_shrinker.count_objects = nfsd_reply_cache_count;
nn->nfsd_reply_cache_shrinker.seeks = 1;
status = register_shrinker(&nn->nfsd_reply_cache_shrinker);
if (status)
return status;
drc_slab = kmem_cache_create("nfsd_drc", sizeof(struct svc_cacherep),
0, 0, NULL);
if (!drc_slab)
nn->drc_slab = kmem_cache_create("nfsd_drc",
sizeof(struct svc_cacherep), 0, 0, NULL);
if (!nn->drc_slab)
goto out_nomem;
drc_hashtbl = kcalloc(hashsize, sizeof(*drc_hashtbl), GFP_KERNEL);
if (!drc_hashtbl) {
drc_hashtbl = vzalloc(array_size(hashsize,
sizeof(*drc_hashtbl)));
if (!drc_hashtbl)
nn->drc_hashtbl = kcalloc(hashsize,
sizeof(*nn->drc_hashtbl), GFP_KERNEL);
if (!nn->drc_hashtbl) {
nn->drc_hashtbl = vzalloc(array_size(hashsize,
sizeof(*nn->drc_hashtbl)));
if (!nn->drc_hashtbl)
goto out_nomem;
}
for (i = 0; i < hashsize; i++) {
INIT_LIST_HEAD(&drc_hashtbl[i].lru_head);
spin_lock_init(&drc_hashtbl[i].cache_lock);
INIT_LIST_HEAD(&nn->drc_hashtbl[i].lru_head);
spin_lock_init(&nn->drc_hashtbl[i].cache_lock);
}
drc_hashsize = hashsize;
nn->drc_hashsize = hashsize;
return 0;
out_nomem:
@ -210,27 +185,28 @@ int nfsd_reply_cache_init(void)
return -ENOMEM;
}
void nfsd_reply_cache_shutdown(void)
void nfsd_reply_cache_shutdown(struct nfsd_net *nn)
{
struct svc_cacherep *rp;
unsigned int i;
unregister_shrinker(&nfsd_reply_cache_shrinker);
unregister_shrinker(&nn->nfsd_reply_cache_shrinker);
for (i = 0; i < drc_hashsize; i++) {
struct list_head *head = &drc_hashtbl[i].lru_head;
for (i = 0; i < nn->drc_hashsize; i++) {
struct list_head *head = &nn->drc_hashtbl[i].lru_head;
while (!list_empty(head)) {
rp = list_first_entry(head, struct svc_cacherep, c_lru);
nfsd_reply_cache_free_locked(&drc_hashtbl[i], rp);
nfsd_reply_cache_free_locked(&nn->drc_hashtbl[i],
rp, nn);
}
}
kvfree(drc_hashtbl);
drc_hashtbl = NULL;
drc_hashsize = 0;
kvfree(nn->drc_hashtbl);
nn->drc_hashtbl = NULL;
nn->drc_hashsize = 0;
kmem_cache_destroy(drc_slab);
drc_slab = NULL;
kmem_cache_destroy(nn->drc_slab);
nn->drc_slab = NULL;
}
/*
@ -245,7 +221,7 @@ lru_put_end(struct nfsd_drc_bucket *b, struct svc_cacherep *rp)
}
static long
prune_bucket(struct nfsd_drc_bucket *b)
prune_bucket(struct nfsd_drc_bucket *b, struct nfsd_net *nn)
{
struct svc_cacherep *rp, *tmp;
long freed = 0;
@ -257,10 +233,10 @@ prune_bucket(struct nfsd_drc_bucket *b)
*/
if (rp->c_state == RC_INPROG)
continue;
if (atomic_read(&num_drc_entries) <= max_drc_entries &&
if (atomic_read(&nn->num_drc_entries) <= nn->max_drc_entries &&
time_before(jiffies, rp->c_timestamp + RC_EXPIRE))
break;
nfsd_reply_cache_free_locked(b, rp);
nfsd_reply_cache_free_locked(b, rp, nn);
freed++;
}
return freed;
@ -271,18 +247,18 @@ prune_bucket(struct nfsd_drc_bucket *b)
* Also prune the oldest ones when the total exceeds the max number of entries.
*/
static long
prune_cache_entries(void)
prune_cache_entries(struct nfsd_net *nn)
{
unsigned int i;
long freed = 0;
for (i = 0; i < drc_hashsize; i++) {
struct nfsd_drc_bucket *b = &drc_hashtbl[i];
for (i = 0; i < nn->drc_hashsize; i++) {
struct nfsd_drc_bucket *b = &nn->drc_hashtbl[i];
if (list_empty(&b->lru_head))
continue;
spin_lock(&b->cache_lock);
freed += prune_bucket(b);
freed += prune_bucket(b, nn);
spin_unlock(&b->cache_lock);
}
return freed;
@ -291,13 +267,19 @@ prune_cache_entries(void)
static unsigned long
nfsd_reply_cache_count(struct shrinker *shrink, struct shrink_control *sc)
{
return atomic_read(&num_drc_entries);
struct nfsd_net *nn = container_of(shrink,
struct nfsd_net, nfsd_reply_cache_shrinker);
return atomic_read(&nn->num_drc_entries);
}
static unsigned long
nfsd_reply_cache_scan(struct shrinker *shrink, struct shrink_control *sc)
{
return prune_cache_entries();
struct nfsd_net *nn = container_of(shrink,
struct nfsd_net, nfsd_reply_cache_shrinker);
return prune_cache_entries(nn);
}
/*
* Walk an xdr_buf and get a CRC for at most the first RC_CSUMLEN bytes
@ -333,11 +315,12 @@ nfsd_cache_csum(struct svc_rqst *rqstp)
}
static int
nfsd_cache_key_cmp(const struct svc_cacherep *key, const struct svc_cacherep *rp)
nfsd_cache_key_cmp(const struct svc_cacherep *key,
const struct svc_cacherep *rp, struct nfsd_net *nn)
{
if (key->c_key.k_xid == rp->c_key.k_xid &&
key->c_key.k_csum != rp->c_key.k_csum)
++payload_misses;
++nn->payload_misses;
return memcmp(&key->c_key, &rp->c_key, sizeof(key->c_key));
}
@ -348,7 +331,8 @@ nfsd_cache_key_cmp(const struct svc_cacherep *key, const struct svc_cacherep *rp
* inserts an empty key on failure.
*/
static struct svc_cacherep *
nfsd_cache_insert(struct nfsd_drc_bucket *b, struct svc_cacherep *key)
nfsd_cache_insert(struct nfsd_drc_bucket *b, struct svc_cacherep *key,
struct nfsd_net *nn)
{
struct svc_cacherep *rp, *ret = key;
struct rb_node **p = &b->rb_head.rb_node,
@ -361,7 +345,7 @@ nfsd_cache_insert(struct nfsd_drc_bucket *b, struct svc_cacherep *key)
parent = *p;
rp = rb_entry(parent, struct svc_cacherep, c_node);
cmp = nfsd_cache_key_cmp(key, rp);
cmp = nfsd_cache_key_cmp(key, rp, nn);
if (cmp < 0)
p = &parent->rb_left;
else if (cmp > 0)
@ -375,14 +359,14 @@ nfsd_cache_insert(struct nfsd_drc_bucket *b, struct svc_cacherep *key)
rb_insert_color(&key->c_node, &b->rb_head);
out:
/* tally hash chain length stats */
if (entries > longest_chain) {
longest_chain = entries;
longest_chain_cachesize = atomic_read(&num_drc_entries);
} else if (entries == longest_chain) {
if (entries > nn->longest_chain) {
nn->longest_chain = entries;
nn->longest_chain_cachesize = atomic_read(&nn->num_drc_entries);
} else if (entries == nn->longest_chain) {
/* prefer to keep the smallest cachesize possible here */
longest_chain_cachesize = min_t(unsigned int,
longest_chain_cachesize,
atomic_read(&num_drc_entries));
nn->longest_chain_cachesize = min_t(unsigned int,
nn->longest_chain_cachesize,
atomic_read(&nn->num_drc_entries));
}
lru_put_end(b, ret);
@ -399,11 +383,12 @@ nfsd_cache_insert(struct nfsd_drc_bucket *b, struct svc_cacherep *key)
int
nfsd_cache_lookup(struct svc_rqst *rqstp)
{
struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id);
struct svc_cacherep *rp, *found;
__be32 xid = rqstp->rq_xid;
__wsum csum;
u32 hash = nfsd_cache_hash(xid);
struct nfsd_drc_bucket *b = &drc_hashtbl[hash];
u32 hash = nfsd_cache_hash(xid, nn);
struct nfsd_drc_bucket *b = &nn->drc_hashtbl[hash];
int type = rqstp->rq_cachetype;
int rtn = RC_DOIT;
@ -419,16 +404,16 @@ nfsd_cache_lookup(struct svc_rqst *rqstp)
* Since the common case is a cache miss followed by an insert,
* preallocate an entry.
*/
rp = nfsd_reply_cache_alloc(rqstp, csum);
rp = nfsd_reply_cache_alloc(rqstp, csum, nn);
if (!rp) {
dprintk("nfsd: unable to allocate DRC entry!\n");
return rtn;
}
spin_lock(&b->cache_lock);
found = nfsd_cache_insert(b, rp);
found = nfsd_cache_insert(b, rp, nn);
if (found != rp) {
nfsd_reply_cache_free_locked(NULL, rp);
nfsd_reply_cache_free_locked(NULL, rp, nn);
rp = found;
goto found_entry;
}
@ -437,11 +422,11 @@ nfsd_cache_lookup(struct svc_rqst *rqstp)
rqstp->rq_cacherep = rp;
rp->c_state = RC_INPROG;
atomic_inc(&num_drc_entries);
drc_mem_usage += sizeof(*rp);
atomic_inc(&nn->num_drc_entries);
nn->drc_mem_usage += sizeof(*rp);
/* go ahead and prune the cache */
prune_bucket(b);
prune_bucket(b, nn);
out:
spin_unlock(&b->cache_lock);
return rtn;
@ -476,7 +461,7 @@ nfsd_cache_lookup(struct svc_rqst *rqstp)
break;
default:
printk(KERN_WARNING "nfsd: bad repcache type %d\n", rp->c_type);
nfsd_reply_cache_free_locked(b, rp);
nfsd_reply_cache_free_locked(b, rp, nn);
}
goto out;
@ -501,6 +486,7 @@ nfsd_cache_lookup(struct svc_rqst *rqstp)
void
nfsd_cache_update(struct svc_rqst *rqstp, int cachetype, __be32 *statp)
{
struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id);
struct svc_cacherep *rp = rqstp->rq_cacherep;
struct kvec *resv = &rqstp->rq_res.head[0], *cachv;
u32 hash;
@ -511,15 +497,15 @@ nfsd_cache_update(struct svc_rqst *rqstp, int cachetype, __be32 *statp)
if (!rp)
return;
hash = nfsd_cache_hash(rp->c_key.k_xid);
b = &drc_hashtbl[hash];
hash = nfsd_cache_hash(rp->c_key.k_xid, nn);
b = &nn->drc_hashtbl[hash];
len = resv->iov_len - ((char*)statp - (char*)resv->iov_base);
len >>= 2;
/* Don't cache excessive amounts of data and XDR failures */
if (!statp || len > (256 >> 2)) {
nfsd_reply_cache_free(b, rp);
nfsd_reply_cache_free(b, rp, nn);
return;
}
@ -534,18 +520,18 @@ nfsd_cache_update(struct svc_rqst *rqstp, int cachetype, __be32 *statp)
bufsize = len << 2;
cachv->iov_base = kmalloc(bufsize, GFP_KERNEL);
if (!cachv->iov_base) {
nfsd_reply_cache_free(b, rp);
nfsd_reply_cache_free(b, rp, nn);
return;
}
cachv->iov_len = bufsize;
memcpy(cachv->iov_base, statp, bufsize);
break;
case RC_NOCACHE:
nfsd_reply_cache_free(b, rp);
nfsd_reply_cache_free(b, rp, nn);
return;
}
spin_lock(&b->cache_lock);
drc_mem_usage += bufsize;
nn->drc_mem_usage += bufsize;
lru_put_end(b, rp);
rp->c_secure = test_bit(RQ_SECURE, &rqstp->rq_flags);
rp->c_type = cachetype;
@ -581,21 +567,26 @@ nfsd_cache_append(struct svc_rqst *rqstp, struct kvec *data)
*/
static int nfsd_reply_cache_stats_show(struct seq_file *m, void *v)
{
seq_printf(m, "max entries: %u\n", max_drc_entries);
struct nfsd_net *nn = v;
seq_printf(m, "max entries: %u\n", nn->max_drc_entries);
seq_printf(m, "num entries: %u\n",
atomic_read(&num_drc_entries));
seq_printf(m, "hash buckets: %u\n", 1 << maskbits);
seq_printf(m, "mem usage: %u\n", drc_mem_usage);
atomic_read(&nn->num_drc_entries));
seq_printf(m, "hash buckets: %u\n", 1 << nn->maskbits);
seq_printf(m, "mem usage: %u\n", nn->drc_mem_usage);
seq_printf(m, "cache hits: %u\n", nfsdstats.rchits);
seq_printf(m, "cache misses: %u\n", nfsdstats.rcmisses);
seq_printf(m, "not cached: %u\n", nfsdstats.rcnocache);
seq_printf(m, "payload misses: %u\n", payload_misses);
seq_printf(m, "longest chain len: %u\n", longest_chain);
seq_printf(m, "cachesize at longest: %u\n", longest_chain_cachesize);
seq_printf(m, "payload misses: %u\n", nn->payload_misses);
seq_printf(m, "longest chain len: %u\n", nn->longest_chain);
seq_printf(m, "cachesize at longest: %u\n", nn->longest_chain_cachesize);
return 0;
}
int nfsd_reply_cache_stats_open(struct inode *inode, struct file *file)
{
return single_open(file, nfsd_reply_cache_stats_show, NULL);
struct nfsd_net *nn = net_generic(file_inode(file)->i_sb->s_fs_info,
nfsd_net_id);
return single_open(file, nfsd_reply_cache_stats_show, nn);
}

14
fs/nfsd/nfsctl.c
View File

@ -1242,6 +1242,9 @@ static __net_init int nfsd_init_net(struct net *net)
goto out_idmap_error;
nn->nfsd_versions = NULL;
nn->nfsd4_minorversions = NULL;
retval = nfsd_reply_cache_init(nn);
if (retval)
goto out_drc_error;
nn->nfsd4_lease = 90; /* default lease time */
nn->nfsd4_grace = 90;
nn->somebody_reclaimed = false;
@ -1254,6 +1257,8 @@ static __net_init int nfsd_init_net(struct net *net)
init_waitqueue_head(&nn->ntf_wq);
return 0;
out_drc_error:
nfsd_idmap_shutdown(net);
out_idmap_error:
nfsd_export_shutdown(net);
out_export_error:
@ -1262,6 +1267,9 @@ static __net_init int nfsd_init_net(struct net *net)
static __net_exit void nfsd_exit_net(struct net *net)
{
struct nfsd_net *nn = net_generic(net, nfsd_net_id);
nfsd_reply_cache_shutdown(nn);
nfsd_idmap_shutdown(net);
nfsd_export_shutdown(net);
nfsd_netns_free_versions(net_generic(net, nfsd_net_id));
@ -1295,9 +1303,6 @@ static int __init init_nfsd(void)
if (retval)
goto out_exit_pnfs;
nfsd_stat_init(); /* Statistics */
retval = nfsd_reply_cache_init();
if (retval)
goto out_free_stat;
nfsd_lockd_init(); /* lockd->nfsd callbacks */
retval = create_proc_exports_entry();
if (retval)
@ -1311,8 +1316,6 @@ static int __init init_nfsd(void)
remove_proc_entry("fs/nfs", NULL);
out_free_lockd:
nfsd_lockd_shutdown();
nfsd_reply_cache_shutdown();
out_free_stat:
nfsd_stat_shutdown();
nfsd_fault_inject_cleanup();
out_exit_pnfs:
@ -1328,7 +1331,6 @@ static int __init init_nfsd(void)
static void __exit exit_nfsd(void)
{
nfsd_reply_cache_shutdown();
remove_proc_entry("fs/nfs/exports", NULL);
remove_proc_entry("fs/nfs", NULL);
nfsd_stat_shutdown();