On Wed, 12 Jan 2011 19:29:30 -0500, Jonathan M Davis <jmdavisp...@gmx.com>
wrote:
On Wednesday, January 12, 2011 15:29:51 %u wrote:
Sorry to bump this up, but is RefCounted(T) really leaking, or am I
missing
something? I would like to use this in my program, and I'm curious as to
why no one responded, since if it's actually leaking, it would be an
important issue.
There probably aren't all that many people who saw your post, and out of
those
who did, there are probably very few - if any - who have actually done
much with
RefCounted. It's fairly new.
There's at least one major bug on Array at the moment (
http://d.puremagic.com/issues/show_bug.cgi?id=4942 ). There are also
several
bugs having to do with destructors at the moment which could be causing
you
problems.
Now, even assuming that you're not seeing any problem with a
destructor-related
bug and that you're not hitting a known bug with Array, there are three
things
that you need to be aware of which would likely show high memory usage
regardless:
1. Array uses an array internally, and there is some caching that goes
on with
regards to arrays that has to do with appending. This means that if
you're
dealing with large arrays, you could have several which haven't been
garbage
collected yet simply because they're cached. Steven Schveighoffer has
talked
about it in several posts, and he has done some work to improve the
situation,
but I'm not sure that any of it has been in a release yet.
No, there is no release yet, but the code is checked into svn. But Array
doesn't use D appending anyways.
2. The garbage collector does not currently run in its own thread. IIUC,
it only
gets run when you try and allocate memory. So, if you allocate a bunch of
memory, and then you never try and allocate memory again, no memory will
be
collected, regardless of whether it's currently being used or not.
3. As I understand it, the current garbage collector _never_ gives
memory back
to the OS. It will reclaim memory that you're not referencing any longer
so that
it doesn't necessarily need to go grab more memory from the OS when you
try and
allocate something, but once the garbage collector has gotten a block of
memory
from the OS, it doesn't give it back. So, currently you will _never_ see
the
memory usage of a D program go down, unless you're explicitly using
malloc and
free instead of GC-allocated memory.
Um... Array acutally uses malloc and free to allocate its data.
But even so, malloc and free have the same property where they don't
always give back memory to the OS. IIUC, Linux can only change the size
of memory it wants, it cannot free pages in the middle of the block.
-Steve
