On Tue, Oct 01, 2002 at 07:23:24AM +0000, Leopold Toetsch wrote:
> # New Ticket Created by Leopold Toetsch
> # Please include the string: [perl #17702]
> # in the subject line of all future correspondence about this issue.
> # <URL: http://rt.perl.org/rt2/Ticket/Display.html?id=17702 >
>
>
> This patch stops parrot from permanently allocating increasing amounts
> of memory:
>
> Please try this:
>
> $ cd languages/perl6
> $ perl6 -B examples/life.p6
> $ cd -
> $ ./parrot -d languages/perl6/examples/life.p6 N
>
> where N is e.g. 1, 10, 100, 1000 and watch memory usage of parrot and
> allocated memory reported by -d.
>
> I tried different things to fix this (e.g correcting the statistics by
> sizeof(struct Memory_Block), omitting the additional allocated 32 bytes
> (what are they used for?) - but this all didn't help.
Applied, nervously. Clearly the previous behavior was not good -- but
was there a reason for it? Does it avoid some worst-case behavior, or
work around a subtle problem?
It was added in revision 1.81, which was a Peter Gibbs and Mike
Lambert patch adding COW support. The relevant chunk is:
@@ -158,10 +169,17 @@ static void compact_pool(struct Parrot_I
/* total-reclaimable == currently used. Add a minimum block to the
* current amount, so we can avoid having to allocate it in the
* future. */
- total_size = pool->total_allocated - pool->reclaimable + pool->minimum_block_size;
- /* total_size = pool->total_allocated; */
- /* TODO: can reduce this by pool->total_reclaimable if we want to
- * be precise */
+ {
+ struct Memory_Block *cur_block, *next_block;
+ total_size = 0;
+ cur_block = pool->top_block;
+ while (cur_block) {
+ total_size += cur_block->size - cur_block->free;
+ cur_block = cur_block->prev;
+ }
+ }
+ total_size += pool->minimum_block_size;
+
/* Snag a block big enough for everything */
new_block = alloc_new_block(interpreter, total_size, pool);
