"Brett E." <brettspamacct@xxxxxxxxxxxxx> said:The key phrase in your post is "as long as RAM is not needed for anything else." My assertion was that this is not the case and it seems to favor cache over pages being used. Sar shows heavy paging to/from disk even though 500 megs are reported in cache. I hope I don't need to go into what paging in/out in succession means regarding paging out pages which we will need shortly after they are paged out. Sar also reports no swapping, hence the need to figure out why there is a disprepency before continuing.
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I created a hack which allocates memory causing cache to go down, then exits, freeing up the malloc'ed memory. This brings free memory up by 400 megs and brings the cache down to close to 0, of course the cache grows right afterwards. It would be nice to cap the cache datastructures in the kernel but I've been posting about this since September to no avail so my expectations are pretty low.
Because it is complete nonsense. Keeping stuff around in RAM in case it
is needed again, as long as RAM is not needed for anything else, is a mayor
win. That is what cache is.