2009-03-31 21:02:44

by Greg Banks

[permalink] [raw]
Subject: [patch 13/29] knfsd: reply cache cleanups

Make REQHASH() an inline function. Rename hash_list to cache_hash.
Fix an obsolete comment.

Signed-off-by: Greg Banks <[email protected]>
---

fs/nfsd/nfscache.c | 29 +++++++++++++++++++----------
include/linux/nfsd/cache.h | 3 +--
2 files changed, 20 insertions(+), 12 deletions(-)

Index: bfields/fs/nfsd/nfscache.c
===================================================================
--- bfields.orig/fs/nfsd/nfscache.c
+++ bfields/fs/nfsd/nfscache.c
@@ -29,15 +29,24 @@
*/
#define CACHESIZE 1024
#define HASHSIZE 64
-#define REQHASH(xid) (((((__force __u32)xid) >> 24) ^ ((__force __u32)xid)) & (HASHSIZE-1))

-static struct hlist_head * hash_list;
+static struct hlist_head * cache_hash;
static struct list_head lru_head;
static int cache_disabled = 1;

+/*
+ * Calculate the hash index from an XID.
+ */
+static inline u32 request_hash(u32 xid)
+{
+ u32 h = xid;
+ h ^= (xid >> 24);
+ return h & (HASHSIZE-1);
+}
+
static int nfsd_cache_append(struct svc_rqst *rqstp, struct kvec *vec);

-/*
+/*
* locking for the reply cache:
* A cache entry is "single use" if c_state == RC_INPROG
* Otherwise, it when accessing _prev or _next, the lock must be held.
@@ -62,8 +71,8 @@ int nfsd_reply_cache_init(void)
i--;
}

- hash_list = kcalloc (HASHSIZE, sizeof(struct hlist_head), GFP_KERNEL);
- if (!hash_list)
+ cache_hash = kcalloc (HASHSIZE, sizeof(struct hlist_head), GFP_KERNEL);
+ if (!cache_hash)
goto out_nomem;

cache_disabled = 0;
@@ -88,8 +97,8 @@ void nfsd_reply_cache_shutdown(void)

cache_disabled = 1;

- kfree (hash_list);
- hash_list = NULL;
+ kfree (cache_hash);
+ cache_hash = NULL;
}

/*
@@ -108,7 +117,7 @@ static void
hash_refile(struct svc_cacherep *rp)
{
hlist_del_init(&rp->c_hash);
- hlist_add_head(&rp->c_hash, hash_list + REQHASH(rp->c_xid));
+ hlist_add_head(&rp->c_hash, cache_hash + request_hash(rp->c_xid));
}

/*
@@ -138,7 +147,7 @@ nfsd_cache_lookup(struct svc_rqst *rqstp
spin_lock(&cache_lock);
rtn = RC_DOIT;

- rh = &hash_list[REQHASH(xid)];
+ rh = &cache_hash[request_hash(xid)];
hlist_for_each_entry(rp, hn, rh, c_hash) {
if (rp->c_state != RC_UNUSED &&
xid == rp->c_xid && proc == rp->c_proc &&
@@ -264,7 +273,7 @@ nfsd_cache_update(struct svc_rqst *rqstp

len = resv->iov_len - ((char*)statp - (char*)resv->iov_base);
len >>= 2;
-
+
/* Don't cache excessive amounts of data and XDR failures */
if (!statp || len > (256 >> 2)) {
rp->c_state = RC_UNUSED;
Index: bfields/include/linux/nfsd/cache.h
===================================================================
--- bfields.orig/include/linux/nfsd/cache.h
+++ bfields/include/linux/nfsd/cache.h
@@ -14,8 +14,7 @@
#include <linux/uio.h>

/*
- * Representation of a reply cache entry. The first two members *must*
- * be hash_next and hash_prev.
+ * Representation of a reply cache entry.
*/
struct svc_cacherep {
struct hlist_node c_hash;

--
Greg


2009-05-12 19:55:01

by J. Bruce Fields

[permalink] [raw]
Subject: Re: [patch 13/29] knfsd: reply cache cleanups

On Wed, Apr 01, 2009 at 07:28:13AM +1100, Greg Banks wrote:
> Make REQHASH() an inline function. Rename hash_list to cache_hash.
> Fix an obsolete comment.

OK--applying for 2.6.31.--b.

>
> Signed-off-by: Greg Banks <[email protected]>
> ---
>
> fs/nfsd/nfscache.c | 29 +++++++++++++++++++----------
> include/linux/nfsd/cache.h | 3 +--
> 2 files changed, 20 insertions(+), 12 deletions(-)
>
> Index: bfields/fs/nfsd/nfscache.c
> ===================================================================
> --- bfields.orig/fs/nfsd/nfscache.c
> +++ bfields/fs/nfsd/nfscache.c
> @@ -29,15 +29,24 @@
> */
> #define CACHESIZE 1024
> #define HASHSIZE 64
> -#define REQHASH(xid) (((((__force __u32)xid) >> 24) ^ ((__force __u32)xid)) & (HASHSIZE-1))
>
> -static struct hlist_head * hash_list;
> +static struct hlist_head * cache_hash;
> static struct list_head lru_head;
> static int cache_disabled = 1;
>
> +/*
> + * Calculate the hash index from an XID.
> + */
> +static inline u32 request_hash(u32 xid)
> +{
> + u32 h = xid;
> + h ^= (xid >> 24);
> + return h & (HASHSIZE-1);
> +}
> +
> static int nfsd_cache_append(struct svc_rqst *rqstp, struct kvec *vec);
>
> -/*
> +/*
> * locking for the reply cache:
> * A cache entry is "single use" if c_state == RC_INPROG
> * Otherwise, it when accessing _prev or _next, the lock must be held.
> @@ -62,8 +71,8 @@ int nfsd_reply_cache_init(void)
> i--;
> }
>
> - hash_list = kcalloc (HASHSIZE, sizeof(struct hlist_head), GFP_KERNEL);
> - if (!hash_list)
> + cache_hash = kcalloc (HASHSIZE, sizeof(struct hlist_head), GFP_KERNEL);
> + if (!cache_hash)
> goto out_nomem;
>
> cache_disabled = 0;
> @@ -88,8 +97,8 @@ void nfsd_reply_cache_shutdown(void)
>
> cache_disabled = 1;
>
> - kfree (hash_list);
> - hash_list = NULL;
> + kfree (cache_hash);
> + cache_hash = NULL;
> }
>
> /*
> @@ -108,7 +117,7 @@ static void
> hash_refile(struct svc_cacherep *rp)
> {
> hlist_del_init(&rp->c_hash);
> - hlist_add_head(&rp->c_hash, hash_list + REQHASH(rp->c_xid));
> + hlist_add_head(&rp->c_hash, cache_hash + request_hash(rp->c_xid));
> }
>
> /*
> @@ -138,7 +147,7 @@ nfsd_cache_lookup(struct svc_rqst *rqstp
> spin_lock(&cache_lock);
> rtn = RC_DOIT;
>
> - rh = &hash_list[REQHASH(xid)];
> + rh = &cache_hash[request_hash(xid)];
> hlist_for_each_entry(rp, hn, rh, c_hash) {
> if (rp->c_state != RC_UNUSED &&
> xid == rp->c_xid && proc == rp->c_proc &&
> @@ -264,7 +273,7 @@ nfsd_cache_update(struct svc_rqst *rqstp
>
> len = resv->iov_len - ((char*)statp - (char*)resv->iov_base);
> len >>= 2;
> -
> +
> /* Don't cache excessive amounts of data and XDR failures */
> if (!statp || len > (256 >> 2)) {
> rp->c_state = RC_UNUSED;
> Index: bfields/include/linux/nfsd/cache.h
> ===================================================================
> --- bfields.orig/include/linux/nfsd/cache.h
> +++ bfields/include/linux/nfsd/cache.h
> @@ -14,8 +14,7 @@
> #include <linux/uio.h>
>
> /*
> - * Representation of a reply cache entry. The first two members *must*
> - * be hash_next and hash_prev.
> + * Representation of a reply cache entry.
> */
> struct svc_cacherep {
> struct hlist_node c_hash;
>
> --
> Greg