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-rw-r--r--libdiskfs/Makefile2
-rw-r--r--libdiskfs/diskfs.h5
-rw-r--r--libdiskfs/node-cache.c107
3 files changed, 55 insertions, 59 deletions
diff --git a/libdiskfs/Makefile b/libdiskfs/Makefile
index 47b93390..803761d1 100644
--- a/libdiskfs/Makefile
+++ b/libdiskfs/Makefile
@@ -61,7 +61,7 @@ MIGSTUBS = fsServer.o ioServer.o fsysServer.o exec_startupServer.o \
startup_notifyServer.o
OBJS = $(sort $(SRCS:.c=.o) $(MIGSTUBS))
-HURDLIBS = fshelp iohelp store ports shouldbeinlibc pager
+HURDLIBS = fshelp iohelp store ports shouldbeinlibc pager ihash
LDLIBS += -lpthread
fsys-MIGSFLAGS = -imacros $(srcdir)/fsmutations.h -DREPLY_PORTS
diff --git a/libdiskfs/diskfs.h b/libdiskfs/diskfs.h
index 11fb0ad1..106aeb06 100644
--- a/libdiskfs/diskfs.h
+++ b/libdiskfs/diskfs.h
@@ -25,6 +25,7 @@
#include <pthread.h>
#include <hurd/ports.h>
#include <hurd/fshelp.h>
+#include <hurd/ihash.h>
#include <hurd/iohelp.h>
#include <idvec.h>
#include <features.h>
@@ -80,8 +81,8 @@ struct peropen
filesystem. */
struct node
{
- /* Links on hash list. */
- struct node *hnext, **hprevp;
+ /* The slot we occupy in the node cache. */
+ hurd_ihash_locp_t slot;
struct disknode *dn;
diff --git a/libdiskfs/node-cache.c b/libdiskfs/node-cache.c
index a76474af..ee7e6fdb 100644
--- a/libdiskfs/node-cache.c
+++ b/libdiskfs/node-cache.c
@@ -17,46 +17,49 @@
You should have received a copy of the GNU General Public License
along with the GNU Hurd. If not, see <http://www.gnu.org/licenses/>. */
-#include "priv.h"
-
-#define INOHSZ 8192
-#if ((INOHSZ&(INOHSZ-1)) == 0)
-#define INOHASH(ino) ((ino)&(INOHSZ-1))
-#else
-#define INOHASH(ino) (((unsigned)(ino))%INOHSZ)
-#endif
+#include <hurd/ihash.h>
-/* The nodehash is a cache of nodes.
+#include "priv.h"
- Access to nodehash and nodehash_nr_items is protected by
- nodecache_lock.
+/* The node cache is implemented using a hash table. Access to the
+ cache is protected by nodecache_lock.
- Every node in the nodehash carries a light reference. When we are
+ Every node in the cache carries a light reference. When we are
asked to give up that light reference, we reacquire our lock
momentarily to check whether someone else reacquired a reference
- through the nodehash. */
-static struct node *nodehash[INOHSZ];
-static size_t nodehash_nr_items;
-static pthread_rwlock_t nodecache_lock = PTHREAD_RWLOCK_INITIALIZER;
+ through the cache. */
+
+/* The size of ino_t is larger than hurd_ihash_key_t on 32 bit
+ platforms. We therefore have to use libihashs generalized key
+ interface. */
+
+/* This is the mix function of fasthash, see
+ https://code.google.com/p/fast-hash/ for reference. */
+#define mix_fasthash(h) ({ \
+ (h) ^= (h) >> 23; \
+ (h) *= 0x2127599bf4325c37ULL; \
+ (h) ^= (h) >> 47; })
-/* Initialize the inode hash table. */
-static void __attribute__ ((constructor))
-nodecache_init ()
+static hurd_ihash_key_t
+hash (const void *key)
{
+ ino_t i;
+ i = *(ino_t *) key;
+ mix_fasthash (i);
+ return (hurd_ihash_key_t) i;
}
-/* Lookup node with inode number INUM. Returns NULL if the node is
- not found in the node cache. */
-static struct node *
-lookup (ino_t inum)
+static int
+compare (const void *a, const void *b)
{
- struct node *np;
- for (np = nodehash[INOHASH(inum)]; np; np = np->hnext)
- if (np->cache_id == inum)
- return np;
- return NULL;
+ return *(ino_t *) a == *(ino_t *) b;
}
+static struct hurd_ihash nodecache =
+ HURD_IHASH_INITIALIZER_GKI (offsetof (struct node, slot), NULL, NULL,
+ hash, compare);
+static pthread_rwlock_t nodecache_lock = PTHREAD_RWLOCK_INITIALIZER;
+
/* Fetch inode INUM, set *NPP to the node structure;
gain one user reference and lock the node. */
error_t __attribute__ ((weak))
@@ -73,9 +76,10 @@ diskfs_cached_lookup_context (ino_t inum, struct node **npp,
{
error_t err;
struct node *np, *tmp;
+ hurd_ihash_locp_t slot;
pthread_rwlock_rdlock (&nodecache_lock);
- np = lookup (inum);
+ np = hurd_ihash_locp_find (&nodecache, (hurd_ihash_key_t) &inum, &slot);
if (np)
goto gotit;
pthread_rwlock_unlock (&nodecache_lock);
@@ -89,7 +93,8 @@ diskfs_cached_lookup_context (ino_t inum, struct node **npp,
/* Put NP in NODEHASH. */
pthread_rwlock_wrlock (&nodecache_lock);
- tmp = lookup (inum);
+ tmp = hurd_ihash_locp_find (&nodecache, (hurd_ihash_key_t) &np->cache_id,
+ &slot);
if (tmp)
{
/* We lost a race. */
@@ -98,13 +103,10 @@ diskfs_cached_lookup_context (ino_t inum, struct node **npp,
goto gotit;
}
- np->hnext = nodehash[INOHASH(inum)];
- if (np->hnext)
- np->hnext->hprevp = &np->hnext;
- np->hprevp = &nodehash[INOHASH(inum)];
- nodehash[INOHASH(inum)] = np;
+ err = hurd_ihash_locp_add (&nodecache, slot,
+ (hurd_ihash_key_t) &np->cache_id, np);
+ assert_perror (err);
diskfs_nref_light (np);
- nodehash_nr_items += 1;
pthread_rwlock_unlock (&nodecache_lock);
/* Get the contents of NP off disk. */
@@ -133,7 +135,7 @@ diskfs_cached_ifind (ino_t inum)
struct node *np;
pthread_rwlock_rdlock (&nodecache_lock);
- np = lookup (inum);
+ np = hurd_ihash_find (&nodecache, (hurd_ihash_key_t) &inum);
pthread_rwlock_unlock (&nodecache_lock);
assert (np);
@@ -144,7 +146,7 @@ void __attribute__ ((weak))
diskfs_try_dropping_softrefs (struct node *np)
{
pthread_rwlock_wrlock (&nodecache_lock);
- if (np->hprevp != NULL)
+ if (np->slot != NULL)
{
/* Check if someone reacquired a reference through the
nodehash. */
@@ -159,12 +161,8 @@ diskfs_try_dropping_softrefs (struct node *np)
return;
}
- *np->hprevp = np->hnext;
- if (np->hnext)
- np->hnext->hprevp = np->hprevp;
- np->hnext = NULL;
- np->hprevp = NULL;
- nodehash_nr_items -= 1;
+ hurd_ihash_locp_remove (&nodecache, np->slot);
+ np->slot = NULL;
diskfs_nrele_light (np);
}
pthread_rwlock_unlock (&nodecache_lock);
@@ -179,7 +177,6 @@ error_t __attribute__ ((weak))
diskfs_node_iterate (error_t (*fun)(struct node *))
{
error_t err = 0;
- int n;
size_t num_nodes;
struct node *node, **node_list, **p;
@@ -191,7 +188,7 @@ diskfs_node_iterate (error_t (*fun)(struct node *))
nodecache_lock, but we can't hold this while locking the
individual node locks). */
/* XXX: Can we? */
- num_nodes = nodehash_nr_items;
+ num_nodes = nodecache.nr_items;
/* TODO This method doesn't scale beyond a few dozen nodes and should be
replaced. */
@@ -203,17 +200,15 @@ diskfs_node_iterate (error_t (*fun)(struct node *))
}
p = node_list;
- for (n = 0; n < INOHSZ; n++)
- for (node = nodehash[n]; node; node = node->hnext)
- {
- *p++ = node;
-
- /* We acquire a hard reference for node, but without using
- diskfs_nref. We do this so that diskfs_new_hardrefs will not
- get called. */
- refcounts_ref (&node->refcounts, NULL);
- }
+ HURD_IHASH_ITERATE (&nodecache, i)
+ {
+ *p++ = node = i;
+ /* We acquire a hard reference for node, but without using
+ diskfs_nref. We do this so that diskfs_new_hardrefs will not
+ get called. */
+ refcounts_ref (&node->refcounts, NULL);
+ }
pthread_rwlock_unlock (&nodecache_lock);
p = node_list;
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-01 07:30:19 +0000