Messages in this thread | | | Date | Mon, 6 Mar 2000 10:56:33 -0500 (EST) | From | Gregory Maxwell <> | Subject | Re: Linux 2.2.15pre12 |
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On Mon, 6 Mar 2000, Paul Jakma wrote:
> another question, forgive me if it's stupid: Why do we even allow > overcommited memory? What reason is there is to support app's that > malloc() a huge amount of memory without using that memory? [snip]
This isn't the only case. Linux uses COW paging on fork. I.e. if an app forks, it doesn't get a seperate copy of pages until it writes to them. This is a termendous speed increase (no copies until needed, cache, etc) and quite a bit of memory savings, but you lose this memory saving if you turn off overcommit.
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