Re: vm in 2.4.5

[J . A . Magallon]

On 05.26 Rik van Riel wrote:
> On Sat, 26 May 2001, J . A . Magallon wrote:
> 
> > It does not begin to use swap in a growing fashion, it just appears
> > full in a moment.
> 
> It gets _allocated_ in a moment, but things don't actually get
> swapped out. This isn't a problem.
> 
> The real problem is that we don't actively reclaim swap space
> when it gets full. We just assign swap to parts of processes,
> but we never reclaim it when we need swap space for something
> else; at least, not until the process exit()s or exec()s.
> 
> > And when all the gcc process ends, my mem ends up like:
> 
> >              total       used       free     shared    buffers     cached
> > Swap:       152576     152576          0
> > 
> > What process do belong the 150Mb of swap ???!!!!
> > Shouldn't that pages have been freed when gcc ends ?
> 
> Linux reclaims swap cache (and swap space) when it encounters
> them in its scan of memory. It doesn't take the trouble of
> freeing the swap on exit() but the swap space will be freed
> later.
> 

That seems to be partially true, if I start just the same comilation when
the first finishes, it behaves like preivous, in the moment the new gcc
needs swap the old swap gets freed, but not the in-core cache, so if I choose
carefully the number of 'puts' lines to stress my system just to the
border, I can't do two times the same 'gcc tst.c'.

-- 
J.A. Magallon                           #  Let the source be with you...        
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Linux Mandrake release 8.1 (Cooker) for i586
Linux werewolf 2.4.4-ac15 #1 SMP Wed May 23 21:55:23 CEST 2001 i686