Re: [PATCH v3 2/2] lockdep: Limit static allocations if PROVE_LOCKING_SMALL is defined

[Babu Moger]

CCing Dave.

Dave, Please ack it if it looks good. Thanks.


On 9/27/2016 2:33 PM, Babu Moger wrote:

Reduce the size of data structure for lockdep entries by half if
PROVE_LOCKING_SMALL if defined. This is used only for sparc.

Signed-off-by: Babu Moger <babu.mo...@oracle.com>
---
  kernel/locking/lockdep_internals.h |   20 +++++++++++++++++---
  1 files changed, 17 insertions(+), 3 deletions(-)

diff --git a/kernel/locking/lockdep_internals.h 
b/kernel/locking/lockdep_internals.h
index 51c4b24..c2b8849 100644
--- a/kernel/locking/lockdep_internals.h
+++ b/kernel/locking/lockdep_internals.h
@@ -46,6 +46,14 @@ enum {
                (LOCKF_USED_IN_HARDIRQ_READ | LOCKF_USED_IN_SOFTIRQ_READ)

/*

+ * CONFIG_PROVE_LOCKING_SMALL is defined for sparc. Sparc requires .text,
+ * .data and .bss to fit in required 32MB limit for the kernel. With
+ * PROVE_LOCKING we could go over this limit and cause system boot-up problems.
+ * So, reduce the static allocations for lockdeps related structures so that
+ * everything fits in current required size limit.
+ */
+#ifdef CONFIG_PROVE_LOCKING_SMALL
+/*
   * MAX_LOCKDEP_ENTRIES is the maximum number of lock dependencies
   * we track.
   *
@@ -54,18 +62,24 @@ enum {
   * table (if it's not there yet), and we check it for lock order
   * conflicts and deadlocks.
   */
+#define MAX_LOCKDEP_ENTRIES    16384UL
+#define MAX_LOCKDEP_CHAINS_BITS        15
+#define MAX_STACK_TRACE_ENTRIES        262144UL
+#else
  #define MAX_LOCKDEP_ENTRIES   32768UL

#define MAX_LOCKDEP_CHAINS_BITS 16

-#define MAX_LOCKDEP_CHAINS     (1UL << MAX_LOCKDEP_CHAINS_BITS)
-
-#define MAX_LOCKDEP_CHAIN_HLOCKS (MAX_LOCKDEP_CHAINS*5)

/*

   * Stack-trace: tightly packed array of stack backtrace
   * addresses. Protected by the hash_lock.
   */
  #define MAX_STACK_TRACE_ENTRIES       524288UL
+#endif
+
+#define MAX_LOCKDEP_CHAINS     (1UL << MAX_LOCKDEP_CHAINS_BITS)
+
+#define MAX_LOCKDEP_CHAIN_HLOCKS (MAX_LOCKDEP_CHAINS*5)

extern struct list_head all_lock_classes;

  extern struct lock_chain lock_chains[];