Messages in this thread | | | Date | Sun, 9 Dec 2001 01:09:33 +0000 (GMT) | From | "Quim K. Holland" <> | Subject | Required Swap for recent 2.4 kernels? |
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It seems that in early days of 2.4.x, the total usable VM used to be not close to sum of the physical RAM and swap. Is this still true for post 2.4.10 kernels?
Back in January 2001, in response to a question about ``recommended swap for 2.4.x'', Rik van Riel answered (quotes '>' are from the messagey by alex@foogod.com):
It has. We now leave dirty pages swapcached, which means that for certain workloads Linux 2.4 eats up much more swap space than Linux 2.2.
On the other hand, if you almost never used swap under Linux 2.2, you probably won't be using it under 2.4 either.
> 2) Subtract the amount of RAM you have > (believe it or not, the more RAM you have, > the less swap you need. Imagine that).
For Linux 2.4, it may be better to substract a bit less, because of the issue above.
If you have a very swap-intensive workload, you may end up with 90% of your memory being "duplicated" in swap, in which case this rule doesn't work.
My understanding is that this answer is not applicable to post 2.4.10 kernels, but if so then would the total usable VM be <physical RAM> + <swap> - <kernel itself> - <kernel overhead that is not proportional to the VM workload>?
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