Messages in this thread | | | Date | Thu, 23 Jul 1998 22:28:39 +0200 (CEST) | From | Rik van Riel <> | Subject | Re: Good and bad news on 2.1.110, and a fix |
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On Thu, 23 Jul 1998, Bill Hawes wrote: > Stephen C. Tweedie wrote: > > > 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. +-------------------------------------------------------------------+ | Linux memory management tour guide. H.H.vanRiel@phys.uu.nl | | Scouting Vries cubscout leader. http://www.phys.uu.nl/~riel/ | +-------------------------------------------------------------------+
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