Re: [PATCH 0/2] Ajust lockdep static allocations

From: Peter Zijlstra
Date: Fri Sep 23 2016 - 03:13:03 EST


On Thu, Sep 22, 2016 at 11:43:34AM -0700, Babu Moger wrote:
> These patches adjust the static allocations for lockdep
> data structures used for debugging locking correctness. The current
> code reserves about 4MB extra space for these data structures. Most
> of the configurations do not need these many data structures. While
> testing, I have not seen it go beyond 20% of already reserved entries.
>
> $grep "lock-classes" /proc/lockdep_stats
> lock-classes: 1560 [max: 8191]
>
> Reserving even more space seems unreasonable. So, keeping the default
> entries small as before the Commit 1413c0389333 ("lockdep: Increase static
> allocations"). Added new CONFIG_PROVE_LOCKING_PLUS in case someone
> needs more entries to debug their large configuration.

Why make this more complicated? There's absolutely no upside to this
change as far as I can see.