Messages in this thread | | | Date | Wed, 06 Jun 2001 14:57:29 -0700 | From | LA Walsh <> | Subject | Re: Break 2.4 VM in five easy steps |
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"Eric W. Biederman" wrote:
> The hard rule will always be that to cover all pathological cases swap > must be greater than RAM. Because in the worse case all RAM will be > in thes swap cache. That this is more than just the worse case in 2.4 > is problematic. I.e. In the worst case: > Virtual Memory = RAM + (swap - RAM).
Hmmm....so my 512M laptop only really has 256M? Um...I regularlly run more than 256M of programs. I don't want it to swap -- its a special, weird condition if I do start swapping. I don't want to waste 1G of HD (5%) for something I never want to use. IRIX runs just fine with swap<RAM. In Irix, your Virtual Memory = RAM + swap. Seems like the Linux kernel requires more swap than other old OS's (SunOS3 (virtual mem = min(mem,swap)). I *thought* I remember that restriction being lifted in SunOS4 when they upgraded the VM. Even though I worked there for 6 years, that was 6 years ago...
> You can't improve the worst case. We can improve the worst case that > many people are facing.
--- Other OS's don't have this pathological 'worst case' scenario. Even my Windows [vm]box seems to operate fine with swap<MEM. On IRIX, virtual space closely approximates physical + disk memory.
> It's worth complaining about. It is also worth digging into and find > out what the real problem is. I have a hunch that this hole > conversation on swap sizes being irritating is hiding the real > problem.
--- Okay, admission of ignorance. When we speak of "swap space", is this term inclusive of both demand paging space and swap-out-entire-programs space or one or another? -linda
-- The above thoughts and | They may have nothing to do with writings are my own. | the opinions of my employer. :-) L A Walsh | Trust Technology, Core Linux, SGI law@sgi.com | Voice: (650) 933-5338
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