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commit d54ad18d9783729ffd7a54458bb0b941f3f14f75
Author: Justus Winter <4winter@informatik.uni-hamburg.de>
Date: Wed Apr 30 02:04:31 2014 +0200
fatfs: improve diskfs_node_iterate
Currently, diskfs_node_iterate iterates twice over all nodes in the
cache. The first time only to determine the number of nodes currently
in the cache. Simply count them instead.
* fatfs/inode.c (nodehash_nr_items): New variable.
(diskfs_cached_lookup): Increment nodehash_nr_items.
(diskfs_cached_lookup_in_dirbuf): Likewise.
(diskfs_node_norefs): Decrement nodehash_nr_items.
(diskfs_node_iterate): Fix the type of num_nodes, use nodehash_nr_items.
diff --git a/fatfs/inode.c b/fatfs/inode.c
index 4229806..ed6f3f0 100644
--- a/fatfs/inode.c
+++ b/fatfs/inode.c
@@ -45,6 +45,7 @@
#endif
static struct node *nodehash[INOHSZ];
+static size_t nodehash_nr_items;
static error_t read_node (struct node *np, vm_address_t buf);
@@ -106,6 +107,7 @@ diskfs_cached_lookup (ino64_t inum, struct node **npp)
dn->hnext->dn->hprevp = &dn->hnext;
dn->hprevp = &nodehash[INOHASH(inum)];
nodehash[INOHASH(inum)] = np;
+ nodehash_nr_items += 1;
pthread_spin_unlock (&diskfs_node_refcnt_lock);
@@ -171,6 +173,7 @@ diskfs_cached_lookup_in_dirbuf (int inum, struct node **npp, vm_address_t buf)
dn->hnext->dn->hprevp = &dn->hnext;
dn->hprevp = &nodehash[INOHASH(inum)];
nodehash[INOHASH(inum)] = np;
+ nodehash_nr_items += 1;
pthread_spin_unlock (&diskfs_node_refcnt_lock);
@@ -216,7 +219,8 @@ diskfs_node_norefs (struct node *np)
*np->dn->hprevp = np->dn->hnext;
if (np->dn->hnext)
np->dn->hnext->dn->hprevp = np->dn->hprevp;
-
+ nodehash_nr_items -= 1;
+
while (last)
{
struct cluster_chain *next = last->next;
@@ -546,7 +550,8 @@ error_t
diskfs_node_iterate (error_t (*fun)(struct node *))
{
error_t err = 0;
- int n, num_nodes = 0;
+ int n;
+ size_t num_nodes;
struct node *node, **node_list, **p;
pthread_spin_lock (&diskfs_node_refcnt_lock);
@@ -557,9 +562,7 @@ diskfs_node_iterate (error_t (*fun)(struct node *))
diskfs_node_refcnt_lock, but we can't hold this while locking the
individual node locks). */
- for (n = 0; n < INOHSZ; n++)
- for (node = nodehash[n]; node; node = node->dn->hnext)
- num_nodes++;
+ num_nodes = nodehash_nr_items;
node_list = alloca (num_nodes * sizeof (struct node *));
p = node_list;
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