Memory power management
Posted Jun 11, 2011 0:29 UTC (Sat) by giraffedata
In reply to: Memory power management
Parent article: Memory power management
I think it's usually the case that essentially all the memory is "used," so I don't get how the proposed policy can be effective. Memory is "used" to varying degrees, i.e. how important the contents are. Some is actually indispensable because there's no practical way to recreate its contents. But other memory is a cache of file contents, cache of dentries, memory that could be moved to swap space, and the like.
There's also internal fragmentation in memory allocation pools -- memory that's used just to anticipate future allocations and save time.
So I don't see any policy that just says power down totally free memory as being terribly useful. We need a policy that weighs for each page the value of having that data in memory vs the cost of powering that page.
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