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From dbff902c41d3e87f2a0491272d5aca80aef29224 Mon Sep 17 00:00:00 2001
From: Justus Winter <4winter@informatik.uni-hamburg.de>
Date: Sun, 7 Jun 2015 00:58:36 +0200
Subject: [PATCH hurd 3/3] libihash: prefer performance degradation over
failure
* libihash/ihash.c (hurd_ihash_add): Add the item even though we are
above the load factor if resizing failed.
---
libihash/ihash.c | 18 +++++++++++++++---
1 file changed, 15 insertions(+), 3 deletions(-)
diff --git a/libihash/ihash.c b/libihash/ihash.c
index a97de3e..c273834 100644
--- a/libihash/ihash.c
+++ b/libihash/ihash.c
@@ -301,18 +301,19 @@ hurd_ihash_add (hurd_ihash_t ht, hurd_ihash_key_t key, hurd_ihash_value_t item)
{
struct hurd_ihash old_ht = *ht;
int was_added;
+ int fatal = 0; /* bail out on allocation errors */
unsigned int i;
if (ht->size)
{
/* Only fill the hash table up to its maximum load factor. */
if (hurd_ihash_get_load (ht) <= ht->max_load)
+ add_one:
if (add_one (ht, key, item))
return 0;
}
/* The hash table is too small, and we have to increase it. */
- ht->nr_items = 0;
if (ht->size == 0)
ht->size = HURD_IHASH_MIN_SIZE;
else
@@ -323,11 +324,22 @@ hurd_ihash_add (hurd_ihash_t ht, hurd_ihash_key_t key, hurd_ihash_value_t item)
if (ht->items == NULL)
{
- *ht = old_ht;
- return ENOMEM;
+ if (fatal || old_ht.size == 0)
+ {
+ *ht = old_ht;
+ return ENOMEM;
+ }
+
+ /* We prefer performance degradation over failure. Therefore,
+ we add the item even though we are above the load factor. If
+ the table is full, this will fail. We set the fatal flag to
+ avoid looping. */
+ fatal = 1;
+ goto add_one;
}
/* We have to rehash the old entries. */
+ ht->nr_items = 0;
for (i = 0; i < old_ht.size; i++)
if (!index_empty (&old_ht, i))
{
--
2.1.4
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