Re: CVS commit: src/sys

[Andrew Doran <ad%netbsd.org@localhost>]

On Sat, Feb 01, 2020 at 02:23:24AM +0000, Taylor R Campbell wrote:

> Module Name:	src
> Committed By:	riastradh
> Date:		Sat Feb  1 02:23:23 UTC 2020
> 
> Modified Files:
> 	src/sys/ddb: db_xxx.c
> 	src/sys/kern: kern_descrip.c kern_sig.c subr_exec_fd.c uipc_socket2.c
> 	    uipc_usrreq.c
> 
> Log Message:
> Load struct fdfile::ff_file with atomic_load_consume.
> 
> Exceptions: when we're only testing whether it's there, not about to
> dereference it.
> 
> Note: We do not use atomic_store_release to set it because the
> preceding mutex_exit should be enough.
> 
> (That said, it's not clear the mutex_enter/exit is needed unless
> refcnt > 0 already, in which case maybe it would be a win to switch
> from the membar implied by mutex_enter to the membar implied by
> atomic_store_release -- which I would generally expect to be much
> cheaper.  And a little clearer without a long comment.)

Likely procfs and sysctl since they go the strongly-locked route.

Andrew