lkml.org 
[lkml]   [2002]   [Sep]   [26]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [patch] 'sticky pages' support in the VM, futex-2.5.38-C5

On Thu, 26 Sep 2002, Linus Torvalds wrote:

> This patch seems trivially broken by having two futexes on the same
> page. When the first futex removes itself, it will clear the sticky
> bit, even though the other futex is still pinning the same page.

sigh. And we cannot even properly detect which unpin_page() was the last
unpinning of the page - there can be so many other reasons a page's count
is elevated. And keeping a page sticky forever is no solution either, the
number of sticky pages would increase significantly, causing real fork()
problems.

> Trust me, you'll have to use the page list approach.

yeah, will try that now. I'm a bit worried about the mandatory cross-CPU
TLB flushes though.

Ingo

-
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: 2005-03-22 13:29    [W:0.028 / U:0.268 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site