lkml.org 
[lkml]   [2004]   [Mar]   [26]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] nodemask_t x86_64 changes [5/7]
> CPU_MASK_ALL ...

Yup - now you tell me ... ;).

I just got done figuring it out in a slightly variant way ... ('nbits'
is NR_CPUS or similar):

#define MASK_LAST_WORD(nbits) \
( \
((nbits) % BITS_PER_LONG) ? \
(1<<((nbits) % BITS_PER_LONG))-1 : ~0UL \
)

#define MASK_ALL(nbits) \
{ { \
[0 ... BITS_TO_LONGS(nbits)-1] = ~0UL, \
[BITS_TO_LONGS(nbits)-1] = MASK_LAST_WORD(nbits) \
} }
This way overwrites the last word of the mask, first putting ~0UL
in all words, then however many bits are needed in the last word.

Does your way work if NR_CPUS is less than BITS_PER_LONG?
Won't gcc complain upon seeing something like, for say
NR_CPUS = 4 on a 32 bit system:

{ [ 0 ... -1 ] = ~0UL, ~0UL << 28 }
with the errors and warnings:

error: empty index range in initializer
warning: excess elements in struct initializer

and shouldn't the last word be inverted: ~(~0UL << NR_CPUS_UNDEF) ?

--
I won't rest till it's the best ...
Programmer, Linux Scalability
Paul Jackson <pj@sgi.com> 1.650.933.1373
-
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 14:01    [from the cache]
©2003-2011 Jasper Spaans