lkml.org 
[lkml]   [2009]   [Dec]   [22]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [this_cpu_xx V8 11/16] Generic support for this_cpu_cmpxchg
On Sat, 19 Dec 2009, Mathieu Desnoyers wrote:

> I am a bit concerned about the "generic" version of this_cpu_cmpxchg.
> Given that what LTTng needs is basically an atomic, nmi-safe version of
> the primitive (on all architectures that have something close to a NMI),
> this means that it could not switch over to your primitives until we add
> the equivalent support we currently have with local_t to all
> architectures. The transition would be faster if we create an
> atomic_cpu_*() variant which would map to local_t operations in the
> initial version.
>
> Or maybe have I missed something in your patchset that address this ?

NMI safeness is not covered by this_cpu operations.

We could add nmi_safe_.... ops?

The atomic_cpu reference make me think that you want full (LOCK)
semantics? Then use the regular atomic ops?


\
 
 \ /
  Last update: 2009-12-22 16:57    [W:0.272 / U:0.016 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site