Re: igc, macOS avoiding signals

[Helmut Eller]

On Mon, Dec 30 2024, Eli Zaretskii wrote:

>> From: Helmut Eller <eller.helmut@gmail.com>
>> Cc: Gerd Möllmann <gerd.moellmann@gmail.com>,  Eli
>>  Zaretskii <eliz@gnu.org>,
>>   spd@toadstyle.org,  emacs-devel@gnu.org
>> Date: Mon, 30 Dec 2024 15:59:08 +0100
>> 
>>   if (mps_arena_busy (<arena>))
>>     plog->gc_count = saturated_add (plog->gc_count, count);
>>   else
>>     record_backtrace (plog, count);
>> 
>> is safe.  If we don't hold the lock, then mps_arena_busy returns false
>> and we can access memory.  We are safe even if another thread has
>> claimed the lock by the time that we reach record_backtrace: the SIGPROF
>> handler will just block until the lock is released.
>
> Which other thread could have claimed the lock?

Any other registered thread that we might have, e.g. the
signal_receiver_thread from Pip's proposal.

Helmut