sbrk(2) broken

Skip Ford skip at
Fri Jan 4 05:53:37 PST 2008

Robert Watson wrote:
> On Fri, 4 Jan 2008, Dag-Erling Smørgrav wrote:
> >Robert Watson <rwatson at> writes:
> >>The right answer is presumably to introduce a new LIMIT_SWAP, which
> >>limits the allocation of anonymous memory by processes, and size it to
> >>something like 90% of swap space by default.
> >
> >Not a good solution on its own.  You need a per-process limit as well, 
> >otherwise a malloc() bomb will still cause other processes to fail 
> >randomly.
> That was what I had in mind, the above should read RLIMIT_SWAP.

Are you referring to the implementation of RLIMIT_SWAP in the
overcommit-disable patch at:

...or some other as yet unwritten implementation?  That patch doesn't
currently do 90% of swap but easily can.  That's been available for almost 3
years now.  I tested it at one point but not lately and it never went into
production.  Do you, and others, have a problem with that implementation?


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