The following commit has been merged in the master branch:
commit b1082ff53ea7d8d2a7c07cbef0b35b1687537c96
Author: Mark Vitale <mvit...@sinenomine.net>
Date: Mon Jul 26 01:24:59 2021 -0400
afs: Assert harder in kernel lock functions
Even if AFS_GLOCK is held, there are still Bad Things that may happen if
someone errs in obtaining or releasing a lock. Protect against some of
them by asserting (when possible) that the lock is in the expected
state, that we actually own a lock we want to release or modify, and
that the readers_reading count can never go negative.
This commit does incur a measurable but insignificant performance hit,
together with:
- Change Ifb057ee76be3364958ab45543b6b63ac3a548571 (afs:
AFS_ASSERT_GLOCK earlier in kernel lock functions)
- Change If97a29182d477dcc1fb7ae62a11e9bcec250e92e (afs: Convert lock
macros to functions)
With these three commits, a simple synthetic benchmark running 10^9
uncontested lock/unlock calls slows down from approximately:
- 3.4s to 3.9s on Linux
- 3.7s to 13.8s on Solaris
And performance of actual client usage hasn't shown any measurable
impact. This should be an acceptable tradeoff for the benefits of safety
and maintainability.
Change-Id: I022be7a50034cd333331b88cc0c0bac78981bb01
Reviewed-on: https://gerrit.openafs.org/14719
Reviewed-by: Mark Vitale <mvit...@sinenomine.net>
Reviewed-by: Cheyenne Wills <cwi...@sinenomine.net>
Tested-by: BuildBot <build...@rampaginggeek.com>
Reviewed-by: Michael Meffie <mmef...@sinenomine.net>
Reviewed-by: Andrew Deason <adea...@sinenomine.net>
src/afs/lock.h | 14 ++++++++++++++
src/rx/rx_rdwr.c | 1 +
2 files changed, 15 insertions(+)
--
OpenAFS Master Repository
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