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authorTrond Myklebust <Trond.Myklebust@netapp.com>2010-05-13 20:51:06 +0400
committerTrond Myklebust <Trond.Myklebust@netapp.com>2010-05-14 23:09:34 +0400
commit93a05e65c090dda9cbd79d0cf57b65c4dbd8da55 (patch)
treebcffc5640b3038292362afb4283965b94f60cc0f /net/sunrpc
parentd300a41ef1c39cc5e6b90fd8834ea7ab16b5c48f (diff)
downloadlinux-93a05e65c090dda9cbd79d0cf57b65c4dbd8da55.tar.xz
SUNRPC: Ensure memory shrinker doesn't waste time in rpcauth_prune_expired()
The 'cred_unused' list, that is traversed by rpcauth_cache_shrinker is ordered by time. If we hit a credential that is under the 60 second garbage collection moratorium, we should exit because we know at that point that all successive credentials are subject to the same moratorium... Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Diffstat (limited to 'net/sunrpc')
-rw-r--r--net/sunrpc/auth.c12
1 files changed, 7 insertions, 5 deletions
diff --git a/net/sunrpc/auth.c b/net/sunrpc/auth.c
index 0667a36aee78..c40856f589f0 100644
--- a/net/sunrpc/auth.c
+++ b/net/sunrpc/auth.c
@@ -236,10 +236,13 @@ rpcauth_prune_expired(struct list_head *free, int nr_to_scan)
list_for_each_entry_safe(cred, next, &cred_unused, cr_lru) {
- /* Enforce a 60 second garbage collection moratorium */
+ /*
+ * Enforce a 60 second garbage collection moratorium
+ * Note that the cred_unused list must be time-ordered.
+ */
if (time_in_range(cred->cr_expire, expired, jiffies) &&
test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags) != 0)
- continue;
+ return 0;
list_del_init(&cred->cr_lru);
number_cred_unused--;
@@ -258,7 +261,7 @@ rpcauth_prune_expired(struct list_head *free, int nr_to_scan)
if (nr_to_scan == 0)
break;
}
- return nr_to_scan;
+ return (number_cred_unused / 100) * sysctl_vfs_cache_pressure;
}
/*
@@ -275,8 +278,7 @@ rpcauth_cache_shrinker(int nr_to_scan, gfp_t gfp_mask)
if (list_empty(&cred_unused))
return 0;
spin_lock(&rpc_credcache_lock);
- nr_to_scan = rpcauth_prune_expired(&free, nr_to_scan);
- res = (number_cred_unused / 100) * sysctl_vfs_cache_pressure;
+ res = rpcauth_prune_expired(&free, nr_to_scan);
spin_unlock(&rpc_credcache_lock);
rpcauth_destroy_credlist(&free);
return res;