[Sugar-devel] poor man's mmap "sliding window" on Python 2.5.x

John Gilmore gnu at toad.com
Wed Jul 8 21:45:23 EDT 2009

> The process is doing a linear read through the file, and is slow
> enough that it appears only to grow. But if I run another process that
> allocates a lot of memory, then the kernel does discard pages pages.

So are you saying that two identical processes that mmap large amounts
of memory, (much larger than the DRAM and with no swap space), then
walk sequentially through the memory, will split the memory evenly
among them, and will complete in a reasonable amount of time.  But one
process will get very slow and never complete?

Sounds like a reproducible test case like that would be worth
reporting to the linux-kernel mailing list, to see if anybody
recognizes the bug, or wants to go hunting it.


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