
%         Registration           Can you handle the pressure? Making Linux    
%                                          bulletproof under load             
%                              Martin J Bligh (mbligh@aracnet.com)            

Operating under memory pressure has been a     
persistent problem for Linux customers.        
Despite significant work done in the 2.6       
kernel to improve its handling of memory, it  
is still easy to make the Linux kernel slow to 
a crawl or lock up completely under load.      
                                                                              
One of the fundamental sources for memory      
pressure is the filesystem pagecache usage,    
along with the \ident{buffer_head} entries that        
control them. Another problem area is inode    
and dentry cache entries in the slab cache.    
Linux struggles to keep either of these under  
control. Userspace processes provide another   
obvious source of memory usage, which are      
partially handled by the OOM killer subsystem, 
which has often been accused of making poor    
decisions on which process to kill.            
                                               
This paper takes a closer look at various      
scenerios causing of memory pressure and the   
way VM handles it currently, what we have done 
to keep the system for falling apart. This     
paper also discusses the future work that      
needs to be done to improve further, which may 
require careful re-design of subsystems.       
                                               
