lkml.org 
[lkml]   [2007]   [Aug]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
SubjectRe: [parisc-linux] [patch 15/23] Add cmpxchg_local to parisc
From
From: Grant Grundler <grundler@parisc-linux.org>
Date: Mon, 27 Aug 2007 15:04:32 -0600

> Doesn't explain the difference between "local" and "non-local" either.
> Per CPU data should only need memory barriers (in some cases) and
> protection against interrupts (in probably more cases). So I'm not
> understanding why a new set of APIs is needed.
>
> Can you add a description to Documentation/atomic_ops.txt ?

My understanding is that the local versions can run without
memory barriers. Only local cpu execution and local interrupt
threads of control can access the variable, and interrupts
force all stores to become visible to the local cpu so an
interrupt can't see the datum from before the atomic update
if one was in progress when the interrupt triggered, and
stuff like that.
-
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: 2007-08-27 23:29    [W:0.101 / U:0.808 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site