SUNRPC: Convert the credential garbage collector into a shrinker callback

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

diff --git a/include/linux/sunrpc/auth.h b/include/linux/sunrpc/auth.h
index e5a3b5141ed2501ed26ee6ca3157acb0047695c4..7a69ca3bebaf8cc33fcd1542d7a8e900774f50aa 100644 (file)
--- a/include/linux/sunrpc/auth.h
+++ b/include/linux/sunrpc/auth.h
@@ -64,8 +64,6 @@ struct rpc_cred {
 struct rpc_cred_cache {
        struct hlist_head       hashtable[RPC_CREDCACHE_NR];
        spinlock_t              lock;
-       unsigned long           nextgc;         /* next garbage collection */
-       unsigned long           expire;         /* cache expiry interval */
 };
 
 struct rpc_authops;
@@ -128,6 +126,8 @@ extern const struct rpc_authops     authunix_ops;
 extern const struct rpc_authops        authnull_ops;
 
 void __init            rpc_init_authunix(void);
+void __init            rpcauth_init_module(void);
+void __exit            rpcauth_remove_module(void);
 
 int                    rpcauth_register(const struct rpc_authops *);
 int                    rpcauth_unregister(const struct rpc_authops *);
@@ -147,7 +147,7 @@ int                 rpcauth_unwrap_resp(struct rpc_task *task, kxdrproc_t decode, void *rqstp,
 int                    rpcauth_refreshcred(struct rpc_task *);
 void                   rpcauth_invalcred(struct rpc_task *);
 int                    rpcauth_uptodatecred(struct rpc_task *);
-int                    rpcauth_init_credcache(struct rpc_auth *, unsigned long);
+int                    rpcauth_init_credcache(struct rpc_auth *);
 void                   rpcauth_destroy_credcache(struct rpc_auth *);
 void                   rpcauth_clear_credcache(struct rpc_cred_cache *);
 

diff --git a/net/sunrpc/auth.c b/net/sunrpc/auth.c
index cf1198d10ee9e0d43ee0afc8645bb591f540b32a..81f4c776c558ef0ebe49318a1435acc5685ac06e 100644 (file)
--- a/net/sunrpc/auth.c
+++ b/net/sunrpc/auth.c
@@ -26,6 +26,7 @@ static const struct rpc_authops *auth_flavors[RPC_AUTH_MAXFLAVOR] = {
 };
 
 static LIST_HEAD(cred_unused);
+static unsigned long number_cred_unused;
 
 static u32
 pseudoflavor_to_flavor(u32 flavor) {
@@ -136,7 +137,7 @@ rpcauth_unhash_cred(struct rpc_cred *cred)
  * Initialize RPC credential cache
  */
 int
-rpcauth_init_credcache(struct rpc_auth *auth, unsigned long expire)
+rpcauth_init_credcache(struct rpc_auth *auth)
 {
        struct rpc_cred_cache *new;
        int i;
@@ -147,8 +148,6 @@ rpcauth_init_credcache(struct rpc_auth *auth, unsigned long expire)
        for (i = 0; i < RPC_CREDCACHE_NR; i++)
                INIT_HLIST_HEAD(&new->hashtable[i]);
        spin_lock_init(&new->lock);
-       new->expire = expire;
-       new->nextgc = jiffies + (expire >> 1);
        auth->au_credcache = new;
        return 0;
 }
@@ -187,7 +186,11 @@ rpcauth_clear_credcache(struct rpc_cred_cache *cache)
                while (!hlist_empty(head)) {
                        cred = hlist_entry(head->first, struct rpc_cred, cr_hash);
                        get_rpccred(cred);
-                       list_move_tail(&cred->cr_lru, &free);
+                       if (!list_empty(&cred->cr_lru)) {
+                               list_del(&cred->cr_lru);
+                               number_cred_unused--;
+                       }
+                       list_add_tail(&cred->cr_lru, &free);
                        rpcauth_unhash_cred_locked(cred);
                }
        }
@@ -214,18 +217,16 @@ rpcauth_destroy_credcache(struct rpc_auth *auth)
 /*
  * Remove stale credentials. Avoid sleeping inside the loop.
  */
-static void
-rpcauth_prune_expired(struct list_head *free)
+static int
+rpcauth_prune_expired(struct list_head *free, int nr_to_scan)
 {
        spinlock_t *cache_lock;
        struct rpc_cred *cred;
 
        while (!list_empty(&cred_unused)) {
                cred = list_entry(cred_unused.next, struct rpc_cred, cr_lru);
-               if (time_after(jiffies, cred->cr_expire +
-                                       cred->cr_auth->au_credcache->expire))
-                       break;
                list_del_init(&cred->cr_lru);
+               number_cred_unused--;
                if (atomic_read(&cred->cr_count) != 0)
                        continue;
                cache_lock = &cred->cr_auth->au_credcache->lock;
@@ -234,23 +235,32 @@ rpcauth_prune_expired(struct list_head *free)
                        get_rpccred(cred);
                        list_add_tail(&cred->cr_lru, free);
                        rpcauth_unhash_cred_locked(cred);
+                       nr_to_scan--;
                }
                spin_unlock(cache_lock);
+               if (nr_to_scan == 0)
+                       break;
        }
+       return nr_to_scan;
 }
 
 /*
- * Run garbage collector.
+ * Run memory cache shrinker.
  */
-static void
-rpcauth_gc_credcache(struct rpc_cred_cache *cache, struct list_head *free)
+static int
+rpcauth_cache_shrinker(int nr_to_scan, gfp_t gfp_mask)
 {
-       if (list_empty(&cred_unused) || time_before(jiffies, cache->nextgc))
-               return;
+       LIST_HEAD(free);
+       int res;
+
+       if (list_empty(&cred_unused))
+               return 0;
        spin_lock(&rpc_credcache_lock);
-       cache->nextgc = jiffies + cache->expire;
-       rpcauth_prune_expired(free);
+       nr_to_scan = rpcauth_prune_expired(&free, nr_to_scan);
+       res = (number_cred_unused / 100) * sysctl_vfs_cache_pressure;
        spin_unlock(&rpc_credcache_lock);
+       rpcauth_destroy_credlist(&free);
+       return res;
 }
 
 /*
@@ -318,7 +328,6 @@ found:
                        cred = ERR_PTR(res);
                }
        }
-       rpcauth_gc_credcache(cache, &free);
        rpcauth_destroy_credlist(&free);
 out:
        return cred;
@@ -408,13 +417,16 @@ put_rpccred(struct rpc_cred *cred)
 need_lock:
        if (!atomic_dec_and_lock(&cred->cr_count, &rpc_credcache_lock))
                return;
-       if (!list_empty(&cred->cr_lru))
+       if (!list_empty(&cred->cr_lru)) {
+               number_cred_unused--;
                list_del_init(&cred->cr_lru);
+       }
        if (test_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags) == 0)
                rpcauth_unhash_cred(cred);
        else if (test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags) != 0) {
                cred->cr_expire = jiffies;
                list_add_tail(&cred->cr_lru, &cred_unused);
+               number_cred_unused++;
                spin_unlock(&rpc_credcache_lock);
                return;
        }
@@ -520,3 +532,18 @@ rpcauth_uptodatecred(struct rpc_task *task)
        return cred == NULL ||
                test_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags) != 0;
 }
+
+
+static struct shrinker *rpc_cred_shrinker;
+
+void __init rpcauth_init_module(void)
+{
+       rpc_init_authunix();
+       rpc_cred_shrinker = set_shrinker(DEFAULT_SEEKS, rpcauth_cache_shrinker);
+}
+
+void __exit rpcauth_remove_module(void)
+{
+       if (rpc_cred_shrinker != NULL)
+               remove_shrinker(rpc_cred_shrinker);
+}

diff --git a/net/sunrpc/auth_gss/auth_gss.c b/net/sunrpc/auth_gss/auth_gss.c
index 068fa6dfb64e0c1c87878aee33cb0b6375e28ff0..8653a92144ae088f2b07a894ad2f4b2cf397b83f 100644 (file)
--- a/net/sunrpc/auth_gss/auth_gss.c
+++ b/net/sunrpc/auth_gss/auth_gss.c
@@ -64,7 +64,6 @@ static const struct rpc_credops gss_credops;
 
 #define NFS_NGROUPS    16
 
-#define GSS_CRED_EXPIRE                (60 * HZ)       /* XXX: reasonable? */
 #define GSS_CRED_SLACK         1024            /* XXX: unused */
 /* length of a krb5 verifier (48), plus data added before arguments when
  * using integrity (two 4-byte integers): */
@@ -643,7 +642,7 @@ gss_create(struct rpc_clnt *clnt, rpc_authflavor_t flavor)
                goto err_put_mech;
        }
 
-       err = rpcauth_init_credcache(auth, GSS_CRED_EXPIRE);
+       err = rpcauth_init_credcache(auth);
        if (err)
                goto err_unlink_pipe;
 

diff --git a/net/sunrpc/auth_unix.c b/net/sunrpc/auth_unix.c
index 205878a3caa5c3ac940e5a03ff3d7928e2ebdf3c..d9c50d810d150376b378bdeb42775c851ecbc82f 100644 (file)
--- a/net/sunrpc/auth_unix.c
+++ b/net/sunrpc/auth_unix.c
@@ -21,8 +21,6 @@ struct unx_cred {
 };
 #define uc_uid                 uc_base.cr_uid
 
-#define UNX_CRED_EXPIRE                (60 * HZ)
-
 #define UNX_WRITESLACK         (21 + (UNX_MAXNODENAME >> 2))
 
 #ifdef RPC_DEBUG
@@ -38,8 +36,7 @@ unx_create(struct rpc_clnt *clnt, rpc_authflavor_t flavor)
 {
        dprintk("RPC:       creating UNIX authenticator for client %p\n",
                        clnt);
-       if (atomic_inc_return(&unix_auth.au_count) == 1)
-               unix_cred_cache.nextgc = jiffies + (unix_cred_cache.expire >> 1);
+       atomic_inc(&unix_auth.au_count);
        return &unix_auth;
 }
 
@@ -232,7 +229,6 @@ const struct rpc_authops authunix_ops = {
 
 static
 struct rpc_cred_cache  unix_cred_cache = {
-       .expire         = UNX_CRED_EXPIRE,
 };
 
 static

diff --git a/net/sunrpc/sunrpc_syms.c b/net/sunrpc/sunrpc_syms.c
index 018065fca84bf934f7d82ba4cede08dc40ebe27c..384c4ad5ab86db1b2e657d46efdd46a609b808a0 100644 (file)
--- a/net/sunrpc/sunrpc_syms.c
+++ b/net/sunrpc/sunrpc_syms.c
@@ -152,7 +152,7 @@ init_sunrpc(void)
        cache_register(&ip_map_cache);
        cache_register(&unix_gid_cache);
        init_socket_xprt();
-       rpc_init_authunix();
+       rpcauth_init_module();
 out:
        return err;
 }
@@ -160,6 +160,7 @@ out:
 static void __exit
 cleanup_sunrpc(void)
 {
+       rpcauth_remove_module();
        cleanup_socket_xprt();
        unregister_rpc_pipefs();
        rpc_destroy_mempool();