Re: [PATCH 02/12] mm: supporting variables and functions for balanced zone aging

On Fri, Dec 02, 2005 at 03:18:11AM +0100, Andrea Arcangeli wrote:
> On Fri, Dec 02, 2005 at 10:04:07AM +0800, Wu Fengguang wrote:
> > btw, maybe it's time to lower the low_mem_reserve.
> > There should be no need to keep ~50M free memory with the balancing patch.
> 
> low_mem_reserve is indipendent from shrink_cache, because shrink_cache can't
> free unfreeable pinned memory.
> 
> If you want to remove low_mem_reserve you'd better start by adding
> migration of memory across the zones with pte updates etc... That would
> at least mitigate the effect of anonymous memory w/o swap. But
> low_mem_reserve is still needed for all other kind of allocations like
> kmalloc or pci_alloc_consistent (i.e. not relocatable) etc...

Thanks for the clarification, I was concerning too much ;)

Regards,
Wu