Re: [PATCH] Linux-2.5 fix/improve get_pid()

[Andrew Morton]

Alan Cox wrote:
> 
> On Fri, 2002-08-09 at 09:48, Helge Hafting wrote:
> > Use 32-bit PID's, but with an additional rule for wraparound.
> > Simply wrap the PID when
> > (nextPID > 2*number_of_processes && nextPID > 30000)
> > The latter one just to avoid wrapping at 10 when there are
> > 5 processes.
> 
> Its much simpler to put max_pid into /proc/sys/kernel. That way we can
> boot with 32000 process ids, which will ensure ancient stuff which has
> 16bit pid_t (old old libc) and also any old kernel interfaces which
> expose it - does ipc ?

procfs oopses with >65535 processes, btw.  Related to the i_ino
encoding:

	#define fake_ino(pid,ino) (((pid)<<16)|(ino))
	#define PROC_INODE_PROPER(inode) ((inode)->i_ino & ~0xffff)

it ruined Anton's evening ;)