Re: [RFC] high system time & lock contention running large mixedworkload

From: Rik van Riel
Date: Tue Dec 01 2009 - 21:05:55 EST


Andrea Arcangeli wrote:
I taken number 7 purely as mentioned by Larry about old code, but I
don't mind what is the actual breakpoint level where we start to send
the ipi flood to destroy all userland tlbs mapping the page so the
young bit can be set by the cpu on the old pte. If you agree with me
at the lowest priority we shouldn't flood ipi and destroy tlb when
there's plenty of clean unmapped clean cache, we already agree ;). If
that's 7 or DEV_PRIORITY-1, that's ok. All I care is that it escalates
gradually, first clean cache and re-activate mapped pages, then when
we're low on clean cache we start to check ptes and unmap whatever is
not found referenced.


The code already does what you propose.

It takes a heavy AIM7 run for Larry to run into the
lock contention issue. I suspect that the page cache
was already very small by the time the lock contention
issue was triggered.

Larry, do you have any more info on the state of the
VM when you see the lock contention?

Also, do you have the latest patches to shrink_list()
by Kosaki and me applied?
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