Re: VM Problems in 2.6.7 (Too active OOM Killer)

[William Lee Irwin III]

On Thu, Jul 15, 2004 at 02:04:38AM +0200, Andrea Arcangeli wrote:
> About the ZONE_NORMAL shortage without swap, rather than running
> cpu-cache-hungry memcopies from lowmemzone to highmem (or even worse to
> pass through swap like it happens in 2.6 mainline with swap enabled), I
> believe it's better to reserve some ram in the lowmem zone, 800M of ram
> on a 32G box should be a cheap price to pay compared to the cpu/IO cost
> involved in moving memory around during the bench.

I wouldn't be so quick to dismiss it. There are enough physical
placement issues already even without pinned userspace pages.
Empowering the kernel to remain largely oblivious to physical placement
of userspace pages would be very convenient and eliminate many problems.
Also, given that the alternatives are IO and allocation failure, I
wouldn't be so quick to dismiss it as slow, either. Unfortunately even
page relocation is only a half-measure while mapping->gfp_mask persists.


-- wli
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