Re: [PATCH] allocation looping + kswapd CPU cycles

[Marcelo Tosatti <marcelo@conectiva.com.br>]

On Thu, 10 May 2001, Stephen C. Tweedie wrote:

> Hi,
> 
> On Thu, May 10, 2001 at 01:43:46PM -0300, Marcelo Tosatti wrote:
> 
> > 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().
> 
> Why?  __GFP_FAIL is only useful as an indication that the caller has
> some magic mechanism for coping with failure.  

Hum, not _only_. 

Initially I thought about __GFP_FAIL to be used by writeout routines which
want to cluster pages until they can allocate memory without causing any
pressure to the system. Something like this: 


while ((page = alloc_page(GFP_FAIL))
	add_page_to_cluster(page);

write_cluster(); 

See?

> There's no other information passed, so a brief call to
> try_to_free_pages is quite appropriate.

This obviously depends on what we decide __GFP_FAIL will be used for.



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