dynamically allocate the name cache and name cache hashing header

SCCS-vsn: sys/kern/vfs_cache.c 7.5

diff --git a/usr/src/sys/kern/vfs_cache.c b/usr/src/sys/kern/vfs_cache.c
index bbba599..f3ea883 100644 (file)
--- a/usr/src/sys/kern/vfs_cache.c
+++ b/usr/src/sys/kern/vfs_cache.c
@@ -14,7 +14,7 @@
  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  *
  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  *

- *     @(#)vfs_cache.c 7.4 (Berkeley) %G%
+ *     @(#)vfs_cache.c 7.5 (Berkeley) %G%

  */
 
 #include "param.h"
  */
 
 #include "param.h"


@@ -23,6 +23,7 @@
 #include "vnode.h"
 #include "namei.h"
 #include "errno.h"
 #include "vnode.h"
 #include "namei.h"
 #include "errno.h"

+#include "malloc.h"

 
 /*
  * Name caching works as follows:
 
 /*
  * Name caching works as follows:


@@ -45,21 +46,15 @@
 /*
  * Structures associated with name cacheing.
  */
 /*
  * Structures associated with name cacheing.
  */

-#define        NCHHASH         128     /* size of hash table */
-
-#if    ((NCHHASH)&((NCHHASH)-1)) != 0
-#define        NHASH(vp, h)    ((((unsigned)(h) >> 6) + (h)) % (NCHHASH))
-#else
-#define        NHASH(vp, h)    ((((unsigned)(h) >> 6) + (h)) & ((NCHHASH)-1))
-#endif
-

 union nchash {
        union   nchash *nch_head[2];
        struct  namecache *nch_chain[2];
 union nchash {
        union   nchash *nch_head[2];
        struct  namecache *nch_chain[2];

-} nchash[NCHHASH];
+} *nchashtbl;

 #define        nch_forw        nch_chain[0]
 #define        nch_back        nch_chain[1]
 
 #define        nch_forw        nch_chain[0]
 #define        nch_back        nch_chain[1]
 

+u_long nchash;                         /* size of hash table - 1 */
+long   numcache;                       /* number of cache entries allocated */

 struct namecache *nchhead, **nchtail;  /* LRU chain pointers */
 struct nchstats nchstats;              /* cache effectiveness statistics */
 
 struct namecache *nchhead, **nchtail;  /* LRU chain pointers */
 struct nchstats nchstats;              /* cache effectiveness statistics */
 


@@ -94,7 +89,7 @@ cache_lookup(ndp)
                return (0);
        }
        dvp = ndp->ni_dvp;
                return (0);
        }
        dvp = ndp->ni_dvp;

-       nhp = &nchash[NHASH(dvp, ndp->ni_hash)];
+       nhp = &nchashtbl[ndp->ni_hash & nchash];

        for (ncp = nhp->nch_forw; ncp != (struct namecache *)nhp;
            ncp = ncp->nc_forw) {
                if (ncp->nc_dvp == dvp &&
        for (ncp = nhp->nch_forw; ncp != (struct namecache *)nhp;
            ncp = ncp->nc_forw) {
                if (ncp->nc_dvp == dvp &&


@@ -184,7 +179,12 @@ cache_enter(ndp)
        /*
         * Free the cache slot at head of lru chain.
         */
        /*
         * Free the cache slot at head of lru chain.
         */

-       if (ncp = nchhead) {
+       if (numcache < desiredvnodes) {
+               ncp = (struct namecache *)
+                       malloc(sizeof *ncp, M_CACHE, M_WAITOK);
+               bzero((char *)ncp, sizeof *ncp);
+               numcache++;
+       } else if (ncp = nchhead) {

                /* remove from lru chain */
                *ncp->nc_prev = ncp->nc_nxt;
                if (ncp->nc_nxt)
                /* remove from lru chain */
                *ncp->nc_prev = ncp->nc_nxt;
                if (ncp->nc_nxt)


@@ -193,48 +193,46 @@ cache_enter(ndp)
                        nchtail = ncp->nc_prev;
                /* remove from old hash chain */
                remque(ncp);
                        nchtail = ncp->nc_prev;
                /* remove from old hash chain */
                remque(ncp);

-               /* grab the inode we just found */
-               ncp->nc_vp = ndp->ni_vp;
-               if (ndp->ni_vp)
-                       ncp->nc_vpid = ndp->ni_vp->v_id;
-               else
-                       ncp->nc_vpid = 0;
-               /* fill in cache info */
-               ncp->nc_dvp = ndp->ni_dvp;
-               ncp->nc_dvpid = ndp->ni_dvp->v_id;
-               ncp->nc_nlen = ndp->ni_namelen;
-               bcopy(ndp->ni_ptr, ncp->nc_name, (unsigned)ncp->nc_nlen);
-               /* link at end of lru chain */
-               ncp->nc_nxt = NULL;
-               ncp->nc_prev = nchtail;
-               *nchtail = ncp;
-               nchtail = &ncp->nc_nxt;
-               /* and insert on hash chain */
-               nhp = &nchash[NHASH(ndp->ni_vp, ndp->ni_hash)];
-               insque(ncp, nhp);
-       }
+       } else
+               return;
+       /* grab the vnode we just found */
+       ncp->nc_vp = ndp->ni_vp;
+       if (ndp->ni_vp)
+               ncp->nc_vpid = ndp->ni_vp->v_id;
+       else
+               ncp->nc_vpid = 0;
+       /* fill in cache info */
+       ncp->nc_dvp = ndp->ni_dvp;
+       ncp->nc_dvpid = ndp->ni_dvp->v_id;
+       ncp->nc_nlen = ndp->ni_namelen;
+       bcopy(ndp->ni_ptr, ncp->nc_name, (unsigned)ncp->nc_nlen);
+       /* link at end of lru chain */
+       ncp->nc_nxt = NULL;
+       ncp->nc_prev = nchtail;
+       *nchtail = ncp;
+       nchtail = &ncp->nc_nxt;
+       /* and insert on hash chain */
+       nhp = &nchashtbl[ndp->ni_hash & nchash];
+       insque(ncp, nhp);

 }
 
 /*
 }
 
 /*

- * Name cache initialization, from main() when we are booting
+ * Name cache initialization, from vfs_init() when we are booting

  */
 nchinit()
 {
        register union nchash *nchp;
  */
 nchinit()
 {
        register union nchash *nchp;

-       register struct namecache *ncp;
+       long nchashsize;

 
        nchhead = 0;
        nchtail = &nchhead;
 
        nchhead = 0;
        nchtail = &nchhead;

-       for (ncp = namecache; ncp < &namecache[nchsize]; ncp++) {
-               ncp->nc_forw = ncp;                     /* hash chain */
-               ncp->nc_back = ncp;
-               ncp->nc_nxt = NULL;                     /* lru chain */
-               *nchtail = ncp;
-               ncp->nc_prev = nchtail;
-               nchtail = &ncp->nc_nxt;
-               /* all else is zero already */
-       }
-       for (nchp = nchash; nchp < &nchash[NCHHASH]; nchp++) {
+       nchashsize = roundup((desiredvnodes + 1) * sizeof *nchp / 2,
+               NBPG * CLSIZE);
+       nchashtbl = (union nchash *)malloc(nchashsize, M_CACHE, M_WAITOK);
+       for (nchash = 1; nchash <= nchashsize / sizeof *nchp; nchash <<= 1)
+               /* void */;
+       nchash = (nchash >> 1) - 1;
+       for (nchp = &nchashtbl[nchash]; nchp >= nchashtbl; nchp--) {

                nchp->nch_head[0] = nchp;
                nchp->nch_head[1] = nchp;
        }
                nchp->nch_head[0] = nchp;
                nchp->nch_head[1] = nchp;
        }


@@ -247,14 +245,18 @@ nchinit()
 cache_purge(vp)
        struct vnode *vp;
 {
 cache_purge(vp)
        struct vnode *vp;
 {

+       union nchash *nhp;

        struct namecache *ncp;
 
        vp->v_id = ++nextvnodeid;
        if (nextvnodeid != 0)
                return;
        struct namecache *ncp;
 
        vp->v_id = ++nextvnodeid;
        if (nextvnodeid != 0)
                return;

-       for (ncp = namecache; ncp < &namecache[nchsize]; ncp++) {
-               ncp->nc_vpid = 0;
-               ncp->nc_dvpid = 0;
+       for (nhp = &nchashtbl[nchash]; nhp >= nchashtbl; nhp--) {
+               for (ncp = nhp->nch_forw; ncp != (struct namecache *)nhp;
+                   ncp = ncp->nc_forw) {
+                       ncp->nc_vpid = 0;
+                       ncp->nc_dvpid = 0;
+               }

        }
        vp->v_id = ++nextvnodeid;
 }
        }
        vp->v_id = ++nextvnodeid;
 }