svn commit: r209119 - head/sys/sys
John Baldwin
jhb at freebsd.org
Mon Jun 14 13:48:27 UTC 2010
On Sunday 13 June 2010 9:41:38 am Lawrence Stewart wrote:
> On 06/13/10 20:10, Pawel Jakub Dawidek wrote:
> > On Sun, Jun 13, 2010 at 02:39:55AM +0000, Lawrence Stewart wrote:
> >> Author: lstewart
> >> Date: Sun Jun 13 02:39:55 2010
> >> New Revision: 209119
> >> URL: http://svn.freebsd.org/changeset/base/209119
> >>
> >> Log:
> >> Add a utility macro to simplify calculating an aggregate sum from a
DPCPU
> >> counter variable.
> >>
> >> Sponsored by: FreeBSD Foundation
> >> Reviewed by: jhb, rpaulo, rwatson (previous version of patch)
> >> MFC after: 1 week
> >>
> >> Modified:
> >> head/sys/sys/pcpu.h
> >>
> >> Modified: head/sys/sys/pcpu.h
> >>
==============================================================================
> >> --- head/sys/sys/pcpu.h Sun Jun 13 01:27:29 2010 (r209118)
> >> +++ head/sys/sys/pcpu.h Sun Jun 13 02:39:55 2010 (r209119)
> >> @@ -106,6 +106,17 @@ extern uintptr_t dpcpu_off[];
> >> #define DPCPU_ID_GET(i, n) (*DPCPU_ID_PTR(i, n))
> >> #define DPCPU_ID_SET(i, n, v) (*DPCPU_ID_PTR(i, n) = v)
> >>
> >> +/*
> >> + * Utility macros.
> >> + */
> >> +#define DPCPU_SUM(n, var, sum) \
> >> +do { \
> >> + (sum) = 0; \
> >> + u_int i; \
> >> + CPU_FOREACH(i) \
> >> + (sum) += (DPCPU_ID_PTR(i, n))->var; \
> >> +} while (0)
> >
> > I'd suggest first swapping variable declaration and '(sum) = 0;'.
>
> Can do (will wait until consensus on other issues is reached first
> before tweaking though).
>
> > Also using 'i' as a counter in macro can easly lead to name collision.
>
> I had a similar concern but after chatting with John on IRC felt it
> wasn't such a big deal in this case.
Actually, I am a fan of using an inline function if possible to avoid the name
collisions.
--
John Baldwin
More information about the svn-src-all
mailing list