linux-kernel - [PATCH 0/2] Ajust lockdep static allocations

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Date:   Thu, 22 Sep 2016 11:43:34 -0700
From:   Babu Moger <babu.moger@...cle.com>
To:     peterz@...radead.org, mingo@...hat.com, akpm@...ux-foundation.org,
        keescook@...omium.org, dan.j.williams@...el.com,
        aryabinin@...tuozzo.com, tj@...nel.org
Cc:     linux-kernel@...r.kernel.org, babu.moger@...cle.com
Subject: [PATCH 0/2] Ajust lockdep static allocations

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.

Patch 1 : Adjusts the sizes based on the new config parameter
patch 2 : Adds new config parameter

Babu Moger (2):
  lockdep: Keep the default static allocations small
  config: Add new CONFIG_PROVE_LOCKING_PLUS

 kernel/locking/lockdep_internals.h |   14 +++++++++++---
 lib/Kconfig.debug                  |   10 ++++++++++
 2 files changed, 21 insertions(+), 3 deletions(-)