Re: [PATCH] allocation looping + kswapd CPU cycles

[Marcelo Tosatti]

On Thu, 10 May 2001, Mark Hemment wrote:

> 
> On Wed, 9 May 2001, Marcelo Tosatti wrote:
> > On Wed, 9 May 2001, Mark Hemment wrote:
> > >   Could introduce another allocation flag (__GFP_FAIL?) which is or'ed
> > > with a __GFP_WAIT to limit the looping?
> > 
> > __GFP_FAIL is in the -ac tree already and it is being used by the bounce
> > buffer allocation code. 
> 
> Thanks for the pointer.
> 
>   For non-zero order allocations, the test against __GFP_FAIL is a little
> too soon; it would be better after we've tried to reclaim pages from the
> inactive-clean list.  Any nasty side effects to this?

No. __GFP_FAIL can to try to reclaim pages from inactive clean.

We just want to avoid __GFP_FAIL allocations from going to
try_to_free_pages().

>   Plus, the code still prevents PF_MEMALLOC processes from using the
> inactive-clean list for non-zero order allocations.  As the trend seems to
> be to make zero and non-zero allocations 'equivalent', shouldn't this
> restriction to lifted?

I don't see any problem about making non-zero allocations be able to
directly reclaim pages.