Understanding Virtual Memory

http://www.redhat.com/magazine/001nov04/features/vm/

by ansgri • 13 years ago

29 5 13 years ago

redhat.com

jeffjose• 13 years ago

The article is a lil dated, but I presume the principles still hold true?

ansgri• 13 years ago

I presume so, because the VM manager is a critical and very stable component.

Even google://'virtual memory "changelog" site:kernel.org' doesn't seem to uncover any significant changes.

lgeek• 13 years ago

I'm not familiar with the VM implementation on Linux, so I don't know if it has changed significantly. I expect it has.

However, a lot of the article seems to be around swapping to disk. We have enough physical memory now that swapping to disk shouldn't regularly happen.

Other things which affect VM design and/or performance on modern systems, but were not much of a concern in 2004: ubiquity of multi-core CPUs, virtualization, use of large pages, 64 bit machines. However, I'm more familiar with academic research than with the state of the mainline kernel.

Edit: Linux is regularly used on lots of non-x86 architectures nowadays, so the VM design might not be so x86-centric anymore.

cpleppert• 13 years ago

The large pages feature (huge pages) still works the same way but the transparent huge pages patch has been integrated recently: http://www.slideshare.net/raghusiddarth/transparent-hugepage...

I personally wouldn't mess with the VM settings the way the author suggests. I don't remember doing that eight years ago anyway even with less RAM on a desktop. On a server you want the working set to fit in RAM anyway and the page cache is already pretty smart.

The best resource is a general kernel book: http://www.amazon.com/Linux-Kernel-Development-3rd-Edition/d...

in terms of the interaction between memory, the cpu, and virtual memory What every Programmer should know about memory should be required reading: http://www.akkadia.org/drepper/cpumemory.pdf

Maven911• 13 years ago

I had no idea that redhat had a magazine, thank you for that

Understanding Virtual Memory

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