Now that we have a couple of large text buffers in the nlm_host struct,
the nlm_host cache should use a slab to reduce memory utilization and
fragmentation on systems that manage a large number of NLM peers.
We keep these hardware cache-aligned to speed up the linked list search
in nlm_lookup_host().
The overhead of creating a fresh nlm_host entry is also reduced using
SLAB's init_once callback instead of using kzalloc().
Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
---
fs/lockd/host.c | 44 ++++++++++++++++++++++++++++++++++++++++++-
fs/lockd/svc.c | 12 +++++++++---
include/linux/lockd/lockd.h | 2 ++
3 files changed, 54 insertions(+), 4 deletions(-)
diff --git a/fs/lockd/host.c b/fs/lockd/host.c
index 4dfe250..015c787 100644
--- a/fs/lockd/host.c
+++ b/fs/lockd/host.c
@@ -25,6 +25,8 @@
#define NLM_HOST_EXPIRE (300 * HZ)
#define NLM_HOST_COLLECT (120 * HZ)
+static struct kmem_cache *nlm_host_cachep;
+
static struct hlist_head nlm_hosts[NLM_HOST_NRHASH];
static unsigned long nlm_next_gc;
static unsigned long nlm_nrhosts;
@@ -609,7 +611,8 @@ nlm_shutdown_hosts(void)
host->h_inuse, host->h_expires);
}
}
- }
+ } else
+ nlm_destroy_host_cache();
}
/*
@@ -651,3 +654,42 @@ nlm_gc_hosts(void)
nlm_next_gc = jiffies + NLM_HOST_COLLECT;
}
+
+static void nlm_host_init_once(void *foo)
+{
+ struct nlm_host *host = (struct nlm_host *)foo;
+
+ INIT_HLIST_NODE(&host->h_hash);
+ host->h_rpcclnt = NULL;
+ init_waitqueue_head(&host->h_gracewait);
+ init_rwsem(&host->h_rwsem);
+ mutex_init(&host->h_mutex);
+ INIT_LIST_HEAD(&host->h_lockowners);
+ spin_lock_init(&host->h_lock);
+ INIT_LIST_HEAD(&host->h_granted);
+ INIT_LIST_HEAD(&host->h_reclaim);
+}
+
+/**
+ * nlm_init_host_cache - create a slab cache for nlm_host entries
+ *
+ */
+int __init nlm_init_host_cache(void)
+{
+ nlm_host_cachep = kmem_cache_create("nlm_host_cache",
+ sizeof(struct nlm_host), 0,
+ SLAB_HWCACHE_ALIGN,
+ nlm_host_init_once);
+ if (nlm_host_cachep == NULL)
+ return -ENOMEM;
+ return 0;
+}
+
+/**
+ * nlm_destroy_host_cache - destroy the slab cache for nlm_host entries
+ *
+ */
+void nlm_destroy_host_cache(void)
+{
+ kmem_cache_destroy(nlm_host_cachep);
+}
diff --git a/fs/lockd/svc.c b/fs/lockd/svc.c
index cdfdc4e..e747e48 100644
--- a/fs/lockd/svc.c
+++ b/fs/lockd/svc.c
@@ -508,12 +508,18 @@ module_param(nsm_use_hostnames, bool, 0644);
static int __init init_nlm(void)
{
+ if (nlm_init_host_cache())
+ return -ENOMEM;
+
#ifdef CONFIG_SYSCTL
nlm_sysctl_table = register_sysctl_table(nlm_sysctl_root);
- return nlm_sysctl_table ? 0 : -ENOMEM;
-#else
- return 0;
+ if (!nlm_sysctl_table) {
+ nlm_destroy_host_cache();
+ return -ENOMEM;
+ }
#endif
+
+ return 0;
}
static void __exit exit_nlm(void)
diff --git a/include/linux/lockd/lockd.h b/include/linux/lockd/lockd.h
index 6fc4f3e..73b3b0c 100644
--- a/include/linux/lockd/lockd.h
+++ b/include/linux/lockd/lockd.h
@@ -214,6 +214,8 @@ void nlmclnt_next_cookie(struct nlm_cookie *);
/*
* Host cache
*/
+int __init nlm_init_host_cache(void);
+void nlm_destroy_host_cache(void);
struct nlm_host *nlmclnt_lookup_host(const struct sockaddr *sap,
const size_t salen,
const unsigned short protocol,
--
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