On Thu, 23 Jul 1998, Bill Hawes wrote:

Stephen C. Tweedie wrote:
 

quoted

The patch to page_alloc.c is a minimal fix for the fragmentation
problem.  It simply records allocation failures for high-order pages,
and forces free_memory_available to return false until a page of at
least that order becomes available.  The impact should be low, since

This sound suspiciously like the first version of
free_memory_available() that Linus introduced in
2.1.89...

One possible downside is that kswapd infinite looping may become more
likely, as we still have no way to determine when the memory

It will happen for sure; just think of what will happen
when that 64 kB DMA allocation fails on your 6 MB box :(

We saw the results in 2.1.89 and I don't see any reason
to repeat the experiments now, at least not until Bill's
patch for freeing inodes is merged...

configuration makes it impossible to achieve the memory goal. I still
see this "swap deadlock" in 110 (and all recent kernels) under low
memory or by doing a swapoff. Any ideas on how to best determine an
infeasible memory configuration?

Well, freepages.high should be a nice hint as to when to
stop; unfortunately it is used now instead of fragmentation
issues.

Maybe we want to count the number of order-3 memory structures
free and keep that number above a certain level (back to
Zlatko's 2.1.59 patch :-).

Rik.
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