lkml.org 
[lkml]   [2007]   [Nov]   [1]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 3/16] read/write_crX, clts and wbinvd for 64-bit paravirt
Glauber de Oliveira Costa wrote:
> I in fact have seen bugs with mixed reads and writes to the same cr,
> (cr4), but adding the volatile
> flag to the read function seemed to fix it.

Well, volatile will make a read be repeated rather than caching the
previous value, but it has no effect on ordering.

> Yet, I agree with you that
> the theorectical problem exists for the reorder, and your proposed fix
> seems fine (although if we're really desperate about memory usage, we
> can use a char instead a int and save 3 bytes!)

Sure. Ideally the compiler would never even generate a reference to it,
and it could just be extern, but in practice the compiler will generate
references sometimes.

J
-
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: 2007-11-01 16:33    [from the cache]
©2003-2014 Jasper Spaans. Advertise on this site