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nfsd4: drc containerization

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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
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 @@ out_nomem:
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 @@ out:
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 @@ found_entry:
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 @@ found_entry:
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 @@ out_export_error:
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 @@ out_free_all:
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 @@ out_unregister_pernet:
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();