lkml.org 
[lkml]   [2005]   [Mar]   [11]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [Linux-fbdev-devel] Re: [ACPI] inappropriate use of in_atomic()

(where'd my cc go?)

Benjamin Herrenschmidt <benh@kernel.crashing.org> wrote:
>
> On Fri, 2005-03-11 at 01:46 -0800, Andrew Morton wrote:
> > Jan Kasprzak <kas@fi.muni.cz> wrote:
> > >
> > > This may be the cause of
> > >
> > > http://bugme.osdl.org/show_bug.cgi?id=4150
> >
> > Looks that way, yes.
>
> Note that it would be interesting to fix that (I mean the reliability of
> is_atomic() or an alternative). I agree it's quite bad to rely on that
> in practice, but there are a few corner cases where it's useful (like
> oops handling in fbdev's etc...)
>

That would require that we increment current->something on every
spin/read/write_lock and decrement it in unlock, even with !CONFIG_PREEMPT.

iirc, Anton added an option to do that to the ppc64 build, decoupled from
CONFIG_PREEMPT (which ppc64 doesn't support).

But it's an appreciable amount of overhead.
-
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 14:11    [W:0.052 / U:0.456 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site