Messages in this thread | | | Date | Thu, 13 Feb 2020 10:11:01 +0100 | From | Peter Zijlstra <> | Subject | Re: [PATCH 3/7] microblaze: Define SMP safe bit operations |
| |
On Thu, Feb 13, 2020 at 09:01:21AM +0000, Stefan Asserhall wrote: > The comment in the generic bitops.h says "You should recode these in the > native assembly language, if at all possible". I don't think using the generic > implementation will be as efficient as the current arch specific one.
That is a very crusty old recommendation. Please look at the compiler generated code.
We've extended the atomic_t operations the past few years and Will wrote the generic atomic bitops for Arm64, we're looking to convert more LL/SC archs to them.
There is currently one known issue with it, but Will has a patch-set pending to solve that (IIRC that only matters if you have stack protector on).
Also see this thread:
https://lkml.kernel.org/r/875zimp0ay.fsf@mpe.ellerman.id.au
And these patches:
https://lkml.kernel.org/r/20200123153341.19947-1-will@kernel.org
| |