lkml.org 
[lkml]   [1999]   [Nov]   [12]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [patch] zoned-2.3.27-E0

On Fri, 12 Nov 1999, Stephen C. Tweedie wrote:

> > Stephen noticed that 2.3.27 doesnt boot on <=16MB boxes due to the zoned
> > allocator changes. The attached patch should fix this. Unfortunately i
> > found no way to prevent introducing the runtime 'nr_zones' variable.
>
> A quick special-case check on zones known to be empty would allow you to
> maintain performance even if you have zones which will never have any
> pages in them on a given machine.

yes, i first did something like this, but it's just as slow in the end.
(well, there is just an academic slowdown anyway)

> You need this anyway --- Alan pointed out that it is a significant hit
> on benchmarks if, during normal running, one zone fills up and you
> start falling back routinely to a lower zone.

at that point we are wasting much more time already walking page tables in
kswapd and try_to_free_pages to free RAM.

and we'd have to get the spinlock to rely on zone->free_pages, and for any
non-page-sized allocation request zone->free_pages is not authorative.

-- mingo


-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.rutgers.edu
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-03-22 13:55    [W:0.068 / U:0.936 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site