On Thu, Nov 15, 2018 at 11:19:24AM -0500, Alan Stern wrote: > Paul and other LKMM maintainers: > > The following series of patches adds support for SRCU to the Linux > Kernel Memory Model. That is, it adds the srcu_read_lock(), > srcu_read_unlock(), and synchronize_srcu() primitives to the model. > > Patch 1/3 does some renaming of the RCU parts of the > memory model's existing CAT code, to help distinguish them > from the upcoming SRCU parts. > > Patch 2/3 refactors the definitions of some RCU relations > in the CAT code, in a way that the SRCU portions will need. > > Patch 3/3 actually adds the SRCU support. > > This new code requires herd7 version 7.51+4(dev) or later (now > available in the herdtools7 github repository) to run. Thanks to Luc > for making the necessary changes to support SRCU.
These patches pass the tests that I have constructed, and also regression tests, very nice! Applied and pushed, thank you. > The code does not check that the index argument passed to > srcu_read_unlock() is the same as the value returned by the > corresponding srcu_read_lock() call. This is deemed to be a semantic > issue, not directly relevant to the memory model. Agreed. If I understand correctly, there are in theory some use cases that these patches do not support, for example: r1 = srcu_read_lock(a); do_1(); r2 = srcu_read_lock(a); do_2(); srcu_read_unlock(a, r1); do_3(); srcu_read_unlock(a, r2); In practice, I would be more worried about this had I ever managed to find a non-bogus use case for this pattern. ;-) Thanx, Paul