Commit-ID: e0944ee63f7249802be74454cef81c97630ae1cd
Gitweb: http://git.kernel.org/tip/e0944ee63f7249802be74454cef81c97630ae1cd
Author: Steven Rostedt <srostedt@xxxxxxxxxx>
AuthorDate: Wed, 20 Apr 2011 21:42:00 -0400
Committer: Ingo Molnar <mingo@xxxxxxx>
CommitDate: Fri, 22 Apr 2011 11:06:59 +0200
lockdep: Remove cmpxchg to update nr_chain_hlocks
For some reason nr_chain_hlocks is updated with cmpxchg, but
this is performed inside of the lockdep global "grab_lock()",
which also makes simple modification of this variable atomic.
Remove the cmpxchg logic for updating nr_chain_hlocks and
simplify the code.
Signed-off-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
Acked-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/20110421014300.727863282@xxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
---
kernel/lockdep.c | 14 ++++----------
1 files changed, 4 insertions(+), 10 deletions(-)
diff --git a/kernel/lockdep.c b/kernel/lockdep.c
index 27c609f..63437d0 100644
--- a/kernel/lockdep.c
+++ b/kernel/lockdep.c
@@ -1973,7 +1973,7 @@ static inline int lookup_chain_cache(struct task_struct *curr,
struct list_head *hash_head = chainhashentry(chain_key);
struct lock_chain *chain;
struct held_lock *hlock_curr, *hlock_next;
- int i, j, n, cn;
+ int i, j;
if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
return 0;
@@ -2033,15 +2033,9 @@ cache_hit:
}
i++;
chain->depth = curr->lockdep_depth + 1 - i;
- cn = nr_chain_hlocks;
- while (cn + chain->depth <= MAX_LOCKDEP_CHAIN_HLOCKS) {
- n = cmpxchg(&nr_chain_hlocks, cn, cn + chain->depth);
- if (n == cn)
- break;
- cn = n;
- }
- if (likely(cn + chain->depth <= MAX_LOCKDEP_CHAIN_HLOCKS)) {
- chain->base = cn;
+ if (likely(nr_chain_hlocks + chain->depth <= MAX_LOCKDEP_CHAIN_HLOCKS)) {
+ chain->base = nr_chain_hlocks;
+ nr_chain_hlocks += chain->depth;
for (j = 0; j < chain->depth - 1; j++, i++) {
int lock_id = curr->held_locks[i].class_idx - 1;
chain_hlocks[chain->base + j] = lock_id;
--
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