CVS commit: src/sys/kern

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

Module Name:    src
Committed By:   ad
Date:           Fri Jan 17 20:26:22 UTC 2020

Modified Files:
        src/sys/kern: kern_lock.c

Log Message:
kernel_lock:

- Defer setting ci_biglock_wanted for a bit, because if curlwp holds a mutex
  or rwlock, and otherlwp is spinning waiting for the mutex/rwlock, setting
  ci_biglock_wanted causes otherlwp to block to avoid deadlock.  If the spin
  on kernel_lock is short there's no point causing trouble.

- Do exponential backoff.

- Put the spinout check under LOCKDEBUG to match the others.


To generate a diff of this commit:
cvs rdiff -u -r1.164 -r1.165 src/sys/kern/kern_lock.c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.