[lttng-dev] [RFC] Deprecating RCU signal flavor

Duncan Sands baldrick at free.fr
Thu May 11 02:57:11 EDT 2023

Hi Olivier, we (DeepBlueCapital) gave up on urcu-signal a long time ago, due to 
the annoying side effects signals can have.  Nowadays we use membarrier, so 
removing urcu-signal is fine as far as we are concerned.

Best wishes, Duncan.

On 10/05/2023 23:10, Olivier Dion via lttng-dev wrote:
> Hi all,
> We have the intention of deprecating the urcu-signal flavor in the
> future.  We are asking users of URCU for _feedback_ on this before
> going any further.
> Part of this decision is that we are adding support for TSAN in URCU and
> the signal flavor deadlocks with TSAN.  It is also my understanding that
> the urcu-signal flavor was historically made as a fallback for system
> lacking the membarrier(2) system call.  Nowadays, most systems have
> support for that system call, making the urcu-signal an artifact of the
> past.
> The following is a proposed timeline of events:
>    1. Asking for feedback from users of URCU (this message)
>    2. Disabling the signal flavor by default and adding --enable-flavor-signal
>    3. Removing the signal flavor

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