malloc(3) ignores RLIMIT_DATA

[Robert Watson]

On Tue, 19 Feb 2008, Jason Evans wrote:

>> As sbrk() is less preferable because of framentation and race conditions, 
>> why not to create mmap() flag MMAP_DSS to check RLIMIT_DATA and to use it 
>> in malloc(3) ?
>
> There has been general agreement among the people I've discussed this issue 
> with that the correct solution is to add a separate resource limit for 
> anonymously mapped memory, which would provide capabilities similar to what 
> your suggestion would provide.

Konstantine has updated his patches and reported on them in the recent status 
report:

   http://www.freebsd.org/news/status/report-2007-10-2007-12.html#VM-Overcommit

Here's the main site for information on the patch:

   http://people.freebsd.org/~kib/overcommit/

He describes a per-uid limit, but I think it might also be useful to have a 
per-process limit tht can also be enforced, although possibly not by default, 
so that protecting applications from each other doesn't require creating 
separate users for them.

Robert N M Watson
Computer Laboratory
University of Cambridge