On Wed, 2012-02-08 at 08:50 -0500, Trond Myklebust wrote:
> On Wed, 2012-02-08 at 07:04 -0500, Jeff Layton wrote:
> > On a x86_64 machine:
> >
> > pre-patch:
> > (gdb) p sizeof(struct idmap)
> > $1 = 39504
> >
> > post-patch:
> > (gdb) p sizeof(struct idmap)
> > $1 = 8784
> >
> > That changes this from an order 4 to an order 2 allocation. Would be
> > even nicer to get it down to under a page, but this will help
> > considerably.
> >
> > Reviewed-by: Jeff Layton <jlayton@xxxxxxxxxx>
>
> We could do that by allocating the two idmap_hashent arrays separately.
> I'll see about that later today.
Here you go... It now ensures that the arrays don't even get allocated
at all if you are using the new idmapper...
8<------------------------------------------------------------------------
>From 8650c9610f9aeeb536a70feacb488dfb6583090e Mon Sep 17 00:00:00 2001
From: Trond Myklebust <Trond.Myklebust@xxxxxxxxxx>
Date: Wed, 8 Feb 2012 13:39:15 -0500
Subject: [PATCH] NFSv4: Further reduce the footprint of the idmapper
Don't allocate the legacy idmapper tables until we actually need
them.
Signed-off-by: Trond Myklebust <Trond.Myklebust@xxxxxxxxxx>
---
fs/nfs/idmap.c | 42 ++++++++++++++++++++++++++++++++++++------
1 files changed, 36 insertions(+), 6 deletions(-)
diff --git a/fs/nfs/idmap.c b/fs/nfs/idmap.c
index fff7948..b5c6d8e 100644
--- a/fs/nfs/idmap.c
+++ b/fs/nfs/idmap.c
@@ -367,7 +367,7 @@ struct idmap_hashent {
struct idmap_hashtable {
__u8 h_type;
- struct idmap_hashent h_entries[IDMAP_HASH_SZ];
+ struct idmap_hashent *h_entries;
};
struct idmap {
@@ -478,21 +478,40 @@ nfs_idmap_new(struct nfs_client *clp)
return 0;
}
+static void
+idmap_alloc_hashtable(struct idmap_hashtable *h)
+{
+ if (h->h_entries != NULL)
+ return;
+ h->h_entries = kcalloc(IDMAP_HASH_SZ,
+ sizeof(*h->h_entries),
+ GFP_KERNEL);
+}
+
+static void
+idmap_free_hashtable(struct idmap_hashtable *h)
+{
+ int i;
+
+ if (h->h_entries == NULL)
+ return;
+ for (i = 0; i < IDMAP_HASH_SZ; i++)
+ kfree(h->h_entries[i].ih_name);
+ kfree(h->h_entries);
+}
+
void
nfs_idmap_delete(struct nfs_client *clp)
{
struct idmap *idmap = clp->cl_idmap;
- int i;
if (!idmap)
return;
nfs_idmap_unregister(clp, idmap->idmap_pipe);
rpc_destroy_pipe_data(idmap->idmap_pipe);
clp->cl_idmap = NULL;
- for (i = 0; i < ARRAY_SIZE(idmap->idmap_user_hash.h_entries); i++)
- kfree(idmap->idmap_user_hash.h_entries[i].ih_name);
- for (i = 0; i < ARRAY_SIZE(idmap->idmap_group_hash.h_entries); i++)
- kfree(idmap->idmap_group_hash.h_entries[i].ih_name);
+ idmap_free_hashtable(&idmap->idmap_user_hash);
+ idmap_free_hashtable(&idmap->idmap_group_hash);
kfree(idmap);
}
@@ -586,6 +605,8 @@ void nfs_idmap_quit(void)
static inline struct idmap_hashent *
idmap_name_hash(struct idmap_hashtable* h, const char *name, size_t len)
{
+ if (h->h_entries == NULL)
+ return NULL;
return &h->h_entries[fnvhash32(name, len) % IDMAP_HASH_SZ];
}
@@ -594,6 +615,8 @@ idmap_lookup_name(struct idmap_hashtable *h, const char *name, size_t len)
{
struct idmap_hashent *he = idmap_name_hash(h, name, len);
+ if (he == NULL)
+ return NULL;
if (he->ih_namelen != len || memcmp(he->ih_name, name, len) != 0)
return NULL;
if (time_after(jiffies, he->ih_expires))
@@ -604,6 +627,8 @@ idmap_lookup_name(struct idmap_hashtable *h, const char *name, size_t len)
static inline struct idmap_hashent *
idmap_id_hash(struct idmap_hashtable* h, __u32 id)
{
+ if (h->h_entries == NULL)
+ return NULL;
return &h->h_entries[fnvhash32(&id, sizeof(id)) % IDMAP_HASH_SZ];
}
@@ -611,6 +636,9 @@ static struct idmap_hashent *
idmap_lookup_id(struct idmap_hashtable *h, __u32 id)
{
struct idmap_hashent *he = idmap_id_hash(h, id);
+
+ if (he == NULL)
+ return NULL;
if (he->ih_id != id || he->ih_namelen == 0)
return NULL;
if (time_after(jiffies, he->ih_expires))
@@ -626,12 +654,14 @@ idmap_lookup_id(struct idmap_hashtable *h, __u32 id)
static inline struct idmap_hashent *
idmap_alloc_name(struct idmap_hashtable *h, char *name, size_t len)
{
+ idmap_alloc_hashtable(h);
return idmap_name_hash(h, name, len);
}
static inline struct idmap_hashent *
idmap_alloc_id(struct idmap_hashtable *h, __u32 id)
{
+ idmap_alloc_hashtable(h);
return idmap_id_hash(h, id);
}
--
1.7.7.6
--
Trond Myklebust
Linux NFS client maintainer
NetApp
Trond.Myklebust@xxxxxxxxxx
www.netapp.com
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