Re: [RFC] Fine-grained memory priorities and PI

From: Andi Kleen
Date: Thu Dec 15 2005 - 08:30:40 EST


> Naturally this is all still in the vaporware stage, but I think that
> if implemented the concept might at least improve the OOM/low-memory
> situation considerably. Starting to fail allocations for the cluster
> programs (including their kernel allocations) well before failing
> them for the swap-fallback tool would help the original poster, and I
> imagine various tweaked priorities would make true OOM-deadlock far
> less likely.

The problem is that deadlocks can happen even without anybody
running out of virtual memory. The deadlocks GFP_CRITICAL
was supposed to handle are deadlocks while swapping out data
because the swapping on some devices needs more memory by itself.
This happens long before anything is running into a true oom.
It's just that the memory cleaning stage cannot make progress
anymore.

Your proposal isn't addressing this problem at all I think.

Handling true OOM is a quite different issue.

-Andi
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