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SUNRPC: Ensure memory shrinker doesn't waste time in rpcauth_prune_expired()

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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>
This commit is contained in:
Trond Myklebust
2010-05-13 12:51:06 -04:00
parent d300a41ef1
commit 93a05e65c0
1 changed files with 7 additions and 5 deletions
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12
net/sunrpc/auth.c
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@@ -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) { 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) && if (time_in_range(cred->cr_expire, expired, jiffies) &&
test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags) != 0) test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags) != 0)
continue; return 0;
list_del_init(&cred->cr_lru); list_del_init(&cred->cr_lru);
number_cred_unused--; number_cred_unused--;
@@ -258,7 +261,7 @@ rpcauth_prune_expired(struct list_head *free, int nr_to_scan)
if (nr_to_scan == 0) if (nr_to_scan == 0)
break; 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)) if (list_empty(&cred_unused))
return 0; return 0;
spin_lock(&rpc_credcache_lock); spin_lock(&rpc_credcache_lock);
nr_to_scan = rpcauth_prune_expired(&free, nr_to_scan); res = rpcauth_prune_expired(&free, nr_to_scan);
res = (number_cred_unused / 100) * sysctl_vfs_cache_pressure;
spin_unlock(&rpc_credcache_lock); spin_unlock(&rpc_credcache_lock);
rpcauth_destroy_credlist(&free); rpcauth_destroy_credlist(&free);
return res; return res;