Threaded 6.4 code compiled under 9.0 uses a lot more memory?..

[Ian Lepore]

On Wed, 2012-10-31 at 13:38 -0700, Adrian Chadd wrote:
> On 31 October 2012 12:06, Konstantin Belousov <kostikbel at gmail.com> wrote:
> 
> > Watchdogd was recently changed to mlock its memory. This is the cause
> > of the RSS increase.
> >
> > If not wired, swapout might cause a delay of the next pat, leading to
> > panic.
> 
> Right, but look at the virtual size of the 6.4 process. It's not 10
> megabytes at all. Even if you wired all of that into memory, it
> wouldn't be 10 megabytes.
> 
> 
> 
> Adrian

After gathering some more evidence, I agree that the huge increase I
noticed in watchdogd is caused by a combo of jemalloc's behavior and the
recent addition of mlockall(2) to watchdogd.  Since this is only
slightly tangentially related to the OP's questions as near as I can
tell, I've entered a PR for it[1], and we can followup with a separate
discusssion thread about that.

While jemalloc can explain the growth in VSZ between 6.4 and 9.x, it
doesn't look like mlockall() has anything to do with the original
question of why the RSZ got so much bigger.  In other words, part of the
original question is still unanswered.

[1]  http://www.freebsd.org/cgi/query-pr.cgi?pr=173332

-- Ian