From: "Ludovic Courtès" <ludo@gnu.org>
To: wingo@igalia.com
Cc: "Ludovic Courtès" <ludo@gnu.org>, 28590@debbugs.gnu.org
Subject: bug#28590: [PATCH 5/7] weak-table: 'move_weak_entry' reports disappeared links.
Date: Tue, 3 Oct 2017 13:43:50 +0200 [thread overview]
Message-ID: <20171003114352.13984-6-ludo@gnu.org> (raw)
In-Reply-To: <20171003114352.13984-1-ludo@gnu.org>
* libguile/weak-table.c (move_weak_entry): Change to return a Boolean.
(give_to_poor): Remove 'copy_weak_entry' call and adjust accordingly.
---
libguile/weak-table.c | 46 +++++++++++++++++++++++++++++-----------------
1 file changed, 29 insertions(+), 17 deletions(-)
diff --git a/libguile/weak-table.c b/libguile/weak-table.c
index b5db3ef48..5c4b3d30a 100644
--- a/libguile/weak-table.c
+++ b/libguile/weak-table.c
@@ -199,28 +199,45 @@ move_disappearing_links (scm_t_weak_entry *from, scm_t_weak_entry *to,
}
}
-static void
+/* Move weak entry FROM to TO. Return non-zero on success, and zero if
+ the entry at FROM disappeared in the meantime. */
+static int
move_weak_entry (scm_t_weak_entry *from, scm_t_weak_entry *to,
scm_t_weak_table_kind kind)
{
if (from->hash)
{
scm_t_weak_entry copy;
-
+
copy_weak_entry (from, ©);
- to->hash = copy.hash;
- to->key = copy.key;
- to->value = copy.value;
- move_disappearing_links (from, to,
- SCM_PACK (copy.key), SCM_PACK (copy.value),
- kind);
+ if (copy.key != 0 && copy.value != 0)
+ {
+ to->hash = copy.hash;
+ to->key = copy.key;
+ to->value = copy.value;
+
+ move_disappearing_links (from, to,
+ SCM_PACK (copy.key), SCM_PACK (copy.value),
+ kind);
+ return 1;
+ }
+ else
+ {
+ /* Lost weak reference: make sure all the disappearing links
+ are registered (in the case of a doubly-weak table, one of
+ the disappearing links could still be there.) */
+ memset (to, '\0', sizeof *to);
+ unregister_disappearing_links (from, kind);
+ return 0;
+ }
}
else
{
+ unregister_disappearing_links (from, kind);
to->hash = 0;
- to->key = 0;
- to->value = 0;
+ to->key = to->value = 0;
+ return 0;
}
}
@@ -301,16 +318,14 @@ give_to_poor (scm_t_weak_table *table, unsigned long k)
{
unsigned long next = (k + 1) % size;
unsigned long hash;
- scm_t_weak_entry copy;
hash = table->entries[next].hash;
if (!hash || hash_to_index (hash, size) == next)
break;
- copy_weak_entry (&table->entries[next], ©);
-
- if (!copy.key || !copy.value)
+ if (!move_weak_entry (&table->entries[next], &table->entries[k],
+ table->kind))
/* Lost weak reference. */
{
give_to_poor (table, next);
@@ -318,9 +333,6 @@ give_to_poor (scm_t_weak_table *table, unsigned long k)
continue;
}
- move_weak_entry (&table->entries[next], &table->entries[k],
- table->kind);
-
k = next;
}
--
2.14.2
next prev parent reply other threads:[~2017-10-03 11:43 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-25 8:49 bug#28590: Weak tables in 2.2.2 grow indefinitely Ludovic Courtès
2017-09-26 9:57 ` Ludovic Courtès
2017-10-02 9:53 ` Ludovic Courtès
2017-10-03 11:43 ` bug#28590: [PATCH 0/7] Attempt to reduce memory growth Ludovic Courtès
2017-10-03 11:43 ` bug#28590: [PATCH 1/7] weak-table: Fix unbounded growth of the disappearing link table Ludovic Courtès
2017-10-03 11:43 ` bug#28590: [PATCH 2/7] weak-table: Stress the GC a little less when resizing Ludovic Courtès
2017-10-03 11:43 ` bug#28590: [PATCH 3/7] weak-table: Make sure 'move_disappearing_links' actually moves links Ludovic Courtès
2017-10-03 11:43 ` bug#28590: [PATCH 4/7] weak-table: Always unregister previous links when inserting an entry Ludovic Courtès
2017-10-03 11:43 ` Ludovic Courtès [this message]
2017-10-03 11:43 ` bug#28590: [PATCH 6/7] weak-table: 'rob_from_rich' accounts for disappeared entries Ludovic Courtès
2017-10-03 11:43 ` bug#28590: [PATCH 7/7] weak-table: Resize less frequently Ludovic Courtès
2017-10-04 13:09 ` bug#28590: [PATCH 0/7] Attempt to reduce memory growth Ludovic Courtès
2017-10-05 14:09 ` Ludovic Courtès
2017-11-07 10:58 ` bug#28590: Weak tables in 2.2.2 grow indefinitely Ludovic Courtès
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