[Kamailio-Devel] Conditional lock_get()

[Iñaki Baz Castillo]

Hi, I've a PCRE compiled object in shared memory.

As far as I read in PCRE documentation, multi-threading read access to the 
same PCRE object is 100% safe so theorically I don't need to use a lock when 
a Kamailio process access to this PCRE object (this would be done in a script 
function).

But I've also a MI command that recompile the PCRE object, so during the 
compilation a lock must exist. This requires "lock_get()" when a process 
tries to read the PCRE object. But this would cause that different processes 
couldn't read the PCRE in parallel, even if it's 100% safe.

Anyway, if I get the desired behaviour it could occur that a process is 
reading the PCRE (so without "lock_get()") and at the same time the MI 
function modifies it, which could cause a segmentation fault.

Any suggestion? Perhaps I should use "lock_get()" in each read access? It's 
the simplest solution, but what about performance?

Thanks.

-- 
Iñaki Baz Castillo