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Facebook folly: https://github.com/facebook/folly/blob/master/folly/synchronization/Rcu.h https://github.com/facebook/folly/blob/master/folly/synchron... Propo

Facebook folly: https://github.com/facebook/folly/blob/master/folly/synchronization/Rcu.h https://github.com/facebook/folly/blob/master/folly/synchron... Proposals for c++ standardization: http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/p0279r1.pdf http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/p027...

TheLoremIpsum 8y ago
How can this be okay if RCU is patented by IBM?
- kjeetgill 8y ago
  Hardly a definitive answer, but it might be worth noting that the C++ proposal was by Paul E. McKenney, paulmck@linux.vnet.ibm.com in the PDF there.
- pgeorgi 8y ago
  The patent it from 2004, so the issue becomes moot in 2024. At least for the C++ standardization that might be a reasonable timeline.
  - zib5KotfeesIr 8y ago
    The main patents have been expired for a while, no? https://en.wikipedia.org/wiki/Read-copy-update#Patents https://en.wikipedia.org/wiki/Read-copy-update#Patents There's a lot of followup patents around optimizations, but it's probably possible to avoid those.
  - gpderetta 8y ago
    IIRC, although some variants might have been patented later, the original patent is form the '90s, so as long as an implementation sticks to what it is described there, it should be safe. IANAL and everything.
- compudj 8y ago
  IBM allowed their RCU contribution to be used in LGPLv2 or later code through this commit they kindly contributed to the Userspace RCU project: commit 54843abcc17c8e8b7600ed635e966c6970d8d20f Author: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Date: Sat May 9 01:11:49 2009 -0400 LGPL relicensing of IBM's contributions Add comments noting IBM's permission to relicense its contributions to the urcu.h and urcu.c files under the LGPLv2 license, or any later version. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Steven L. Bennett <steven.bennett@us.ibm.com>
  - nbsd4life 8y ago
    That only refers to copyright, not the patent, right? I know FOSS projects avoiding a different implementation of RCU for patent reasons.
    - lostmsu 8y ago
      Doesn't LGPLv2 give explicit patent grant?
      - compudj 8y ago
        GPLv2 provides implicit patent grant in section 6 and section 7. LGPLv2.1 has basically the same content in section 10 and section 11. IANAL, but AFAIU LGPLv2.1 provides implicit patent grant in the same way as GPLv2. IBM has allowed use of RCU in GPL code through its contributions to the Linux kernel for many years now. Their contributions to Userspace RCU provide an implicit patent grant in a similar fashion. Userspace RCU being LGPLv2.1, it allows proprietary applications to link to it, and therefore use RCU through the library APIs, as long as they satisfy LGPLv2.1 requirements.
drewg123 8y ago
There is also Concurrency Kit, which uses RCU-like mechanisms in a BSD licensed library: https://github.com/concurrencykit/ck https://github.com/concurrencykit/ck

TheLoremIpsum 8y ago

How can this be okay if RCU is patented by IBM?

kjeetgill 8y ago
Hardly a definitive answer, but it might be worth noting that the C++ proposal was by Paul E. McKenney, paulmck@linux.vnet.ibm.com in the PDF there.
pgeorgi 8y ago
The patent it from 2004, so the issue becomes moot in 2024. At least for the C++ standardization that might be a reasonable timeline.
- zib5KotfeesIr 8y ago
  The main patents have been expired for a while, no? https://en.wikipedia.org/wiki/Read-copy-update#Patents https://en.wikipedia.org/wiki/Read-copy-update#Patents There's a lot of followup patents around optimizations, but it's probably possible to avoid those.
- gpderetta 8y ago
  IIRC, although some variants might have been patented later, the original patent is form the '90s, so as long as an implementation sticks to what it is described there, it should be safe. IANAL and everything.
compudj 8y ago
IBM allowed their RCU contribution to be used in LGPLv2 or later code through this commit they kindly contributed to the Userspace RCU project: commit 54843abcc17c8e8b7600ed635e966c6970d8d20f Author: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Date: Sat May 9 01:11:49 2009 -0400 LGPL relicensing of IBM's contributions Add comments noting IBM's permission to relicense its contributions to the urcu.h and urcu.c files under the LGPLv2 license, or any later version. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Steven L. Bennett <steven.bennett@us.ibm.com>
- nbsd4life 8y ago
  That only refers to copyright, not the patent, right? I know FOSS projects avoiding a different implementation of RCU for patent reasons.
  - lostmsu 8y ago
    Doesn't LGPLv2 give explicit patent grant?
    - compudj 8y ago
      GPLv2 provides implicit patent grant in section 6 and section 7. LGPLv2.1 has basically the same content in section 10 and section 11. IANAL, but AFAIU LGPLv2.1 provides implicit patent grant in the same way as GPLv2. IBM has allowed use of RCU in GPL code through its contributions to the Linux kernel for many years now. Their contributions to Userspace RCU provide an implicit patent grant in a similar fashion. Userspace RCU being LGPLv2.1, it allows proprietary applications to link to it, and therefore use RCU through the library APIs, as long as they satisfy LGPLv2.1 requirements.

drewg123 8y ago

There is also Concurrency Kit, which uses RCU-like mechanisms in a BSD licensed library: https://github.com/concurrencykit/ck https://github.com/concurrencykit/ck