Max groups one can be a member of linux/sched.h and NGROUPS_SMALL

[Joseph Pingenot]

Hello.

In my quest to try and figure out the max number of groups one can be a
  member of (and to learn more about the kernel internals), I stumbled
  across the following tidbit:

(excerpted from linux/sched.h)
#define NGROUPS_SMALL           32
#define NGROUPS_PER_BLOCK       ((int)(PAGE_SIZE / sizeof(gid_t)))
struct group_info {
        int ngroups;
        atomic_t usage;
        gid_t small_block[NGROUPS_SMALL];
        int nblocks;
        gid_t *blocks[0];
};

This seems to be the place where group information is stored (linked to from
  task_struct).

So, it appears to hold 32 gids, but what is this blocks bit?  Is 32 the max
  number of groups one can be a member of?

Thanks!

-Joseph

-- 
Joseph===============================================trelane@xxxxxxxxxxxxxx
      Graduate Student in Physics, Freelance Free Software Developer
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