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9b710506a0
Change the bitops operation to be naturally "long", i.e. 63 bits on the 64-bit kernel. Additional bugs are likely to crop up in the future. We already have bugs which machines with > 16 TiB of memory in a single node, as can happen if memory is interleaved. The x86 bitop operations take a signed index, so using an unsigned type is not an option. Jim Kukunas measured the effect of this patch on kernel size: it adds 2779 bytes to the allyesconfig kernel. Some of that probably could be elided by replacing the inline functions with macros which select the 32-bit type if the index is a 32-bit value, something like: In that case we could also use "Jr" constraints for the 64-bit version. However, this would more than double the amount of code for a relatively small gain. Note that we can't use ilog2() for _BITOPS_LONG_SHIFT, as that causes a recursive header inclusion problem. The change to constant_test_bit() should both generate better code and give correct result for negative bit indicies. As previously written the compiler had to generate extra code to create the proper wrong result for negative values. Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> Cc: Jim Kukunas <james.t.kukunas@intel.com> Link: http://lkml.kernel.org/n/tip-z61ofiwe90xeyb461o72h8ya@git.kernel.org |
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