KernelTrap: Swap Pre-Fetching

“Con Kolivas posted a patch for the 2.6.13 kernel that
implements cache prefetching. The patch is based on earlier work by
Thomas Schlichter. Con explains, ‘I have resuscitated and rewritten
some early prefetch code Thomas Schlichter did in late 2.5 to
create a configurable kernel thread that reads in swap from ram in
reverse order it was written out. It does this once kswapd has been
idle for a minute (implying no current vm stress).’ He goes on to
explain, ‘Note that swapped in pages are kept on backing store
(swap), meaning no further I/O is required if the page needs to
swap back out…'”

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