Memory pools implementation in C

Question

I am looking for a good memory pool implementation in C.

it should include the following:

1. Anti fragmentation.
2. Be super fast :)
3. Ability to "bundle" several allocations from different sizes under some identifier and delete all the allocations with the given identifier.
4. Thread safe

Answer 1

Have you looked into

• nedmalloc http://www.nedprod.com/programs/portable/nedmalloc/
• ptmalloc http://www.malloc.de/en/

Both leverage a memory pool but keep it mostly transparent to the user.

In general, you will find best performance in your own custom memory pool (you can optimize for your pattern). I ended up writing a few for different access patterns.

Answer 2

I think the excellent talloc, developed as part of samba might be what you're looking for. The part I find most interesting is that any pointer returned from talloc is a valid memory context. Their example is:

struct foo *X = talloc(mem_ctx, struct foo);
X->name = talloc_strdup(X, "foo");
// ...
talloc_free(X); // frees memory for both X and X->name

In response to your particular points:

(1) Not sure what anti-fragmentation is in this case. In C you're not going to get compacting garbage collection anyway, so I think your choices are somewhat limited.

(2) It advertises being only 4% slower than plain malloc(3), which is quite fast.

(3) See example above.

(4) It is thread safe as long as different threads use different contexts & the underlying malloc is thread safe.