lkml.org 
[lkml]   [2005]   [Nov]   [8]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH]: Cleanup of __alloc_pages
Nick wrote:
> Because it is on the other side of an &&, which evaulates to a
> constant zero when !CONFIG_CPUSETS.

Ah so.

> Having __GFP_HIGH as its own flag gives some more flexibility. I
> don't think it has a downside?

With respect to GFP_ATOMIC, __GFP_HIGH has no flexibility, as they are
#defined to be the same thing.

With respect to __GFP_WAIT, if we only ever use it exactly when
we don't use __GFP_HIGH aka GFP_ATOMIC, then there is a definite
downside. My old brain doesn't fold constants nearly as reliably or
rapidly as a compiler. Every apparent degree of freedom that is unused
wastes a few of my remaining precious neurons understanding it.
It directly leads to such bugs as the one I noted in my last reply,
when I realized that checking cpusets in the 'ignoring mins' case
was bogus.

__GFP_HIGH has a second cost - it is easily confused with __GFP_HIGHMEM.

> That would be good. I'll send off a fresh patch with the
> ALLOC_WATERMARKS fixed after Rohit gets around to looking over
> it.

Good.

--
I won't rest till it's the best ...
Programmer, Linux Scalability
Paul Jackson <pj@sgi.com> 1.925.600.0401
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-11-08 07:25    [W:0.067 / U:1.220 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site