Messages in this thread | | | Date | Tue, 21 Mar 2000 09:04:04 -0800 (PST) | From | David Whysong <> | Subject | Re: Overcommitable memory?? |
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[CC list trimmed again, I doubt Stephen Tweedie or Rik van Riel are interested in this discussion.]
On Tue, 21 Mar 2000, James Sutherland wrote:
>>Preventing system OOM using resource limits is equivalent to disabling >>overcommit. You have to restrict each of N users to 1/N of the total >>system memory. > >No. That is NOT overcommit. Overcommit, in this context, is when a >process calls malloc() and is given unpopulated address space, which >will be populated on use.
In the quota case, in order to prevent a system-wide OOM you must give each of N users an average of 1/N of the total system memory (ignoring kernel overhead). The side effect is that overcommittment is now impossible, because the system can only be overcommitted if a user has exceeded their quota, which is not allowed...
Unless you don't count COW pages against a user's quota?
Dave
David Whysong dwhysong@physics.ucsb.edu Astrophysics graduate student University of California, Santa Barbara My public PGP keys are on my web page - http://www.physics.ucsb.edu/~dwhysong DSS PGP Key 0x903F5BD6 : FE78 91FE 4508 106F 7C88 1706 B792 6995 903F 5BD6 D-H PGP key 0x5DAB0F91 : BC33 0F36 FCCD E72C 441F 663A 72ED 7FB7 5DAB 0F91
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