Messages in this thread | | | Date | Mon, 19 Oct 2009 09:30:39 +0200 | From | Ingo Molnar <> | Subject | Re: [PATCH 3/2] perf tools: Use DECLARE_BITMAP instead of an open-coded array |
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* Frederic Weisbecker <fweisbec@gmail.com> wrote:
> On Sat, Oct 17, 2009 at 05:57:18PM +0200, Frederic Weisbecker wrote: > > Use DECLARE_BITMAP instead of an open coded array for our bitmap > > of featured sections. > > > > This makes the array an unsigned long instead of a u64 but since we > > use a 256 bits bitmap, the array size shouldn't vary between > > different boxes. > > That said I would really feel more comfortable if someone can confirm > that.
Should be size-invariant for the bitmap size of 256 bits due to:
#define DECLARE_BITMAP(name,bits) \ unsigned long name[BITS_TO_LONGS(bits)]
but it's not little-endian/big-endian invariant.
We should at minimum save the CPU architecture (and endianness parameters) the data got generated on, and reject endianness-incompatible uses - so that if someone wants to add cross-endian support it can be implemented cleanly.
Ingo
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