Re: 0-order allocation problem

[Rik van Riel <riel@conectiva.com.br>]

On Wed, 15 Aug 2001, Linus Torvalds wrote:
> On Wed, 15 Aug 2001, Marcelo Tosatti wrote:
> >
> >  __GFP_IO is not going to help us that much on anon intensive workloads
> > (eg swapoff). Remember we are _never_ going to block on buffer_head's of
> > on flight swap pages because we can't see them in page_launder(). (if a
> > page is locked, we simply skip it)
>
> Note that that is what we have the page_alloc (and buffer head)
> reserves for - and it doesn't take that much to get the ball rolling.
> Certainly not even close to our low-water-marks.. And once it
> snowballs it _does_ help that people call page_launder().

Also, page_launder() tends to "strip" the buffer heads
from pages as soon as they get cleaned, making them
immediately available to the process trying to allocate
a buffer head and calling page_launder() from buffer.c

regards,

Rik
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