lkml.org 
[lkml]   [2021]   [Jun]   [16]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH] locking/lockdep: unlikely bfs error check
From
Date


> On Jun 16, 2021, at 10:48 PM, Waiman Long <llong@redhat.com> wrote:
>
> On 6/16/21 10:42 AM, Xiongwei Song wrote:
>> From: Xiongwei Song <sxwjean@gmail.com>
>>
>> The error from graph walk is small probability event, so unlikely
>> bfs_error can improve performance a little bit.
>>
>> Signed-off-by: Xiongwei Song <sxwjean@gmail.com>
>> ---
>> kernel/locking/lockdep.c | 12 ++++++------
>> 1 file changed, 6 insertions(+), 6 deletions(-)
>>
>> diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
>> index 074fd6418c20..af8c9203cd3e 100644
>> --- a/kernel/locking/lockdep.c
>> +++ b/kernel/locking/lockdep.c
>> @@ -2646,7 +2646,7 @@ static int check_irq_usage(struct task_struct *curr, struct held_lock *prev,
>> bfs_init_rootb(&this, prev);
>> ret = __bfs_backwards(&this, &usage_mask, usage_accumulate, usage_skip, NULL);
>> - if (bfs_error(ret)) {
>> + if (unlikely(bfs_error(ret))) {
>> print_bfs_bug(ret);
>> return 0;
>> }
>> @@ -2664,7 +2664,7 @@ static int check_irq_usage(struct task_struct *curr, struct held_lock *prev,
>> bfs_init_root(&that, next);
>> ret = find_usage_forwards(&that, forward_mask, &target_entry1);
>> - if (bfs_error(ret)) {
>> + if (unlikely(bfs_error(ret))) {
>> print_bfs_bug(ret);
>> return 0;
>> }
>> @@ -2679,7 +2679,7 @@ static int check_irq_usage(struct task_struct *curr, struct held_lock *prev,
>> backward_mask = original_mask(target_entry1->class->usage_mask);
>> ret = find_usage_backwards(&this, backward_mask, &target_entry);
>> - if (bfs_error(ret)) {
>> + if (unlikely(bfs_error(ret))) {
>> print_bfs_bug(ret);
>> return 0;
>> }
>> @@ -2998,7 +2998,7 @@ check_prev_add(struct task_struct *curr, struct held_lock *prev,
>> * Is the <prev> -> <next> link redundant?
>> */
>> ret = check_redundant(prev, next);
>> - if (bfs_error(ret))
>> + if (unlikely(bfs_error(ret)))
>> return 0;
>> else if (ret == BFS_RMATCH)
>> return 2;
>> @@ -3911,7 +3911,7 @@ check_usage_forwards(struct task_struct *curr, struct held_lock *this,
>> bfs_init_root(&root, this);
>> ret = find_usage_forwards(&root, usage_mask, &target_entry);
>> - if (bfs_error(ret)) {
>> + if (unlikely(bfs_error(ret))) {
>> print_bfs_bug(ret);
>> return 0;
>> }
>> @@ -3946,7 +3946,7 @@ check_usage_backwards(struct task_struct *curr, struct held_lock *this,
>> bfs_init_rootb(&root, this);
>> ret = find_usage_backwards(&root, usage_mask, &target_entry);
>> - if (bfs_error(ret)) {
>> + if (unlikely(bfs_error(ret))) {
>> print_bfs_bug(ret);
>> return 0;
>> }
>
> I think it is better to put the unlikely() directly into the bfs_error() inline function instead of sprinkling it all over the place.

Sounds good. Thank you for the suggestion. I will update the patch.

Regards,
Xiongwei

>
> Cheers,
> Longman
>

\
 
 \ /
  Last update: 2021-06-16 17:00    [W:0.381 / U:0.128 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site