The following commit has been merged into the locking/core branch of tip:
Commit-ID: bd7b5ae26618ad2bd6f6264e2cb6c5815d323e75
Gitweb: https://git.kernel.org/tip/bd7b5ae26618ad2bd6f6264e2cb6c5815d323e75
Author: Carlos Llamas <cmllamas@xxxxxxxxxx>
AuthorDate: Thu, 24 Oct 2024 18:36:28
Committer: Boqun Feng <boqun.feng@xxxxxxxxx>
CommitterDate: Sun, 15 Dec 2024 11:49:35 -08:00
lockdep: Document MAX_LOCKDEP_CHAIN_HLOCKS calculation
Define a macro AVG_LOCKDEP_CHAIN_DEPTH to document the magic number '5'
used in the calculation of MAX_LOCKDEP_CHAIN_HLOCKS. The number
represents the estimated average depth (number of locks held) of a lock
chain. The calculation of MAX_LOCKDEP_CHAIN_HLOCKS was first added in
commit 443cd507ce7f ("lockdep: add lock_class information to lock_chain
and output it").
Suggested-by: Waiman Long <longman@xxxxxxxxxx>
Cc: Huang Ying <ying.huang@xxxxxxxxx>
Cc: J. R. Okajima <hooanon05g@xxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Boqun Feng <boqun.feng@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Acked-by: Waiman Long <longman@xxxxxxxxxx>
Signed-off-by: Carlos Llamas <cmllamas@xxxxxxxxxx>
Acked-by: "Huang, Ying" <ying.huang@xxxxxxxxx>
Signed-off-by: Boqun Feng <boqun.feng@xxxxxxxxx>
Link: https://lore.kernel.org/r/20241024183631.643450-4-cmllamas@xxxxxxxxxx
---
kernel/locking/lockdep_internals.h | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/kernel/locking/lockdep_internals.h b/kernel/locking/lockdep_internals.h
index bbe9000..20f9ef5 100644
--- a/kernel/locking/lockdep_internals.h
+++ b/kernel/locking/lockdep_internals.h
@@ -119,7 +119,8 @@ static const unsigned long LOCKF_USED_IN_IRQ_READ =
#define MAX_LOCKDEP_CHAINS (1UL << MAX_LOCKDEP_CHAINS_BITS)
-#define MAX_LOCKDEP_CHAIN_HLOCKS (MAX_LOCKDEP_CHAINS*5)
+#define AVG_LOCKDEP_CHAIN_DEPTH 5
+#define MAX_LOCKDEP_CHAIN_HLOCKS (MAX_LOCKDEP_CHAINS * AVG_LOCKDEP_CHAIN_DEPTH)
extern struct lock_chain lock_chains[];
|