> Even if you disable overcommit, I don't think you will get pages assigned when you allocate. If your allocations don't trigger an allocation failure, you should get the same behavior with respect to disk cache using otherwise unused pages.

Doesn't really change the point. The RAM might not be completely wasted, but given that near every app will over-allocate and just use the pooled memory, you will waste memory that could otherwise be used to run more stuff.

And it can be quite significant, like it's pretty common for server apps to start a big process and then have COWed thread per connection in a pool, so your apache2 eating maybe 60MB per thread in pool is now in gigabytes range at very small pool sizes.

Blog is essentially call to "let's make apps like we did in the DOS era" which is ridiculus