Re: new OOM heuristic failure (was: Re: VM: qsbench)

[Stephan von Krawczynski]

> Hi,                                                                 
>                                                                     
> shrink_caches can end up lying.  shrink_dcache_memory and friends do
not tell                                                              
> shrink_caches how many pages they free so nr_pages can be bogus...  
Is it worth                                                           
> fixing?  The simpliest, harmlessly racey and not too pretty, code   
follows.  It                                                          
> would also not be hard to change the shrink_ calls to return the    
number of pages                                                       
> shrunk, but this would hit more code...                             
>                                                                     
> Comments?                                                           
                                                                      
I believe the idea of having a more precise nr_pages value can make a 
difference. We are trying to estimate if swapping is needed, which is 
pretty expensive. If we can avoid it by more accurately knowing what  
is really going on (without _too_ much costs) we can only win.        
                                                                      
Regards,                                                              
Stephan