Hello!
On Sat, 13 May 2006, Matthew D. Fuller wrote:
On Sat, May 13, 2006 at 11:58:26AM -0400 I heard the voice of
Kris Kennaway, and lo! it spake thus:
FYI, INVARIANTS adds checks but does not (is not supposed to) divert
code paths.
It does at least in UMA; it does a lot of bzero()/NULL'ing out of
memory, which might hide later uninitialized-use bugs that could bite
you without it (and, of course, probably burns a fair chunk of CPU to
do it ;). I know I've heard other cases over the past 5 years or so;
that's the only one I've heard recently or can check, but I wouldn't
be too surprised if there were others.
This is exactly the point of my suggestion: use separate option (e.g.,
INVARIANTS_EXTENDED) for this additional bzero()/NULL'ing and other
performance-expensive checks, and leave only simple asserts under
basic INVARIANTS options. IMHO this will encourage (or, at least,
not discourage) use of INVARIANTS-enabled kernels in production
conditions which for sure will help to analyze latent, heavy load-specific,
bugs.
Matthew Fuller (MF4839) | [EMAIL PROTECTED]
Systems/Network Administrator | http://www.over-yonder.net/~fullermd/
On the Internet, nobody can hear you scream.
Sincerely, Dmitry
--
Atlantis ISP, System Administrator
e-mail: [EMAIL PROTECTED]
nic-hdl: LYNX-RIPE
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