malloc not behaving well when brk space is limited?

[u-igbb@aetey.se]

Hello,

Background:
 Compiling a native musl-based toolchain for ia32 on Linux 2.6+.
 Using the standalone dynamic loader mode.
 (The latter seems to lead to a quite limited heap space, by kernel
 behaviour/design)

I encounter out of memory errors. A look at the malloc source does not
find any fallback to mmap when heap is exhausted. What would you suggest
as a suitable approach to make it work?

Somebody has possibly already encountered and solved this with musl?

I see also reports about a related out of memory problem with
pae-executables which means a solution might help many musl users.

The other standard libraries I am using (glibc, uclibc) seem to happily
switch to allocation from mmap() when the heap is full. I understand
that this costs some code and performance but a breakup is no good either.

Any ideas? Maintaining and using an external libmalloc or substituting
malloc in musl? This feels like quite a burden...
(Would musl internal calls to malloc notice the external library
and resolve to its entry points instead of the internal malloc?)

Rune