Messages in this thread | | | Date | Wed, 16 Apr 2003 16:07:15 +0200 | From | Andi Kleen <> | Subject | Re: Reduce struct page by 8 bytes on 64bit |
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On Wed, Apr 16, 2003 at 02:45:21PM +0200, David S. Miller wrote: > From: Andi Kleen <ak@muc.de> > Date: Tue, 15 Apr 2003 13:24:30 +0200 > > I worked around this by declaring a new data type atomic_bitmask32 > with matching set_bit32/clear_bit32 etc. interfaces. Currently only > on x86-64 aomitc_bitmask32 is defined to unsigned, everybody else > still uses unsigned long. The other 64bit architectures can define it to > unsigned too if they can confirm that it's ok to do. > > I have no problem with this. > > If you are clever, you can define a generic version even for the > "unsigned long" 64-bit platforms. It's left as an exercise to > the reader :-)
How so? Of course I could write an generic set_bit32, but the question is if these bit operations would be still atomic on SMP and not conflict with fields occuping the same 8 byte slot. I remember you flaming someone some time ago because he used set_bit in an atomic fashion on a type smaller than unsigned long for example.
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