Re: Increase PTHREAD_KEYS_MAX

[christos%astron.com@localhost (Christos Zoulas)]

In article <20150513082708.GI25832%homeworld.netbsd.org@localhost>,
Emmanuel Dreyfus  <manu%netbsd.org@localhost> wrote:
>Hello
>
>pthread_key_create() will refuse to create to create more than 
>PTHREAD_KEYS_MAX pthread_key_t. I encountered situations
>where some Apache setup with various modules could not work 
>reliabily on NetBSD because the value is too low. From time
>to time the server enters a state where it will not be able
>to serve requests.
>
>POSIX mandates PTHREAD_KEYS_MAX to be at least _POSIX_THREAD_KEYS_MAX, 
>which should be 128 according to POSIX:
>http://pubs.opengroup.org/onlinepubs/009695399/basedefs/limits.h.html
>Oddly it is 256 in NetBSD's <limit.h>
>
>The values are:
>NetBSD 256
>Linux: 1024
>MacOS X: 512
>
>Obviously we lag behind and software will suit NetBSD less and less over the
>time. Since it is often the result of shared usage by modules from different 
>developers, we cannot blame anyone for overflowing _POSIX_THREAD_KEYS_MAX
>usage as a requirement.
>
>I suggest for netbsd-7
>- fix _POSIX_THREAD_KEYS_MAX to be 128 instad of 256
>- increase PTHREAD_KEYS_MAX to 2048 so that we lead again for some time
>  this would increase memory footprint of programs linked with -lpthread
>  of 14 kB on ILP32 systems, and 28 kB on LP64 systems.
>
>And for later:
>- Think about a dynamic allocation. For now we have an array, could we
>have a queue?

Just make it an array that is dynamically allocated based on an environment
variable; this is what others do (it seems).

christos