From: Xiongwei Song <sxwjean@me.com>
To: peterz@infradead.org, mingo@redhat.com, will@kernel.org,
longman@redhat.com, boqun.feng@gmail.com
Cc: linux-kernel@vger.kernel.org, Xiongwei Song <sxwjean@gmail.com>
Subject: [PATCH v2 1/3] locking/lockdep: Unlikely bfs_error() inside
Date: Fri, 18 Jun 2021 22:55:32 +0800 [thread overview]
Message-ID: <20210618145534.438816-2-sxwjean@me.com> (raw)
In-Reply-To: <20210618145534.438816-1-sxwjean@me.com>
From: Xiongwei Song <sxwjean@gmail.com>
The error from graph walk is small probability event, and there are some
bfs_error calls during lockdep detection, so unlikely bfs_error inside
can improve performance a little bit.
Suggested-by: Waiman Long <longman@redhat.com>
Signed-off-by: Xiongwei Song <sxwjean@gmail.com>
---
kernel/locking/lockdep.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 7641bd407239..a8a66a2a9bc1 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -1540,7 +1540,7 @@ enum bfs_result {
*/
static inline bool bfs_error(enum bfs_result res)
{
- return res < 0;
+ return unlikely(res < 0);
}
/*
@@ -2089,7 +2089,7 @@ check_path(struct held_lock *target, struct lock_list *src_entry,
ret = __bfs_forwards(src_entry, target, match, skip, target_entry);
- if (unlikely(bfs_error(ret)))
+ if (bfs_error(ret))
print_bfs_bug(ret);
return ret;
@@ -2936,7 +2936,7 @@ check_prev_add(struct task_struct *curr, struct held_lock *prev,
* in the graph whose neighbours are to be checked.
*/
ret = check_noncircular(next, prev, trace);
- if (unlikely(bfs_error(ret) || ret == BFS_RMATCH))
+ if (bfs_error(ret) || unlikely(ret == BFS_RMATCH))
return 0;
if (!check_irq_usage(curr, prev, next))
--
2.30.2
next prev parent reply other threads:[~2021-06-18 14:56 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-18 14:55 [PATCH v2 0/3] some improvements for lockdep Xiongwei Song
2021-06-18 14:55 ` Xiongwei Song [this message]
2021-06-18 14:55 ` [PATCH v2 2/3] locking/lockdep: Unlikely conditons about BFS_RMATCH Xiongwei Song
2021-06-18 14:55 ` [PATCH v2 3/3] locking/lockdep: Print possible warning after counting deps Xiongwei Song
2021-06-24 8:03 ` Xiongwei Song
2021-06-24 13:45 ` Boqun Feng
2021-07-12 8:19 ` [PATCH v2 0/3] some improvements for lockdep Xiongwei Song
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20210618145534.438816-2-sxwjean@me.com \
--to=sxwjean@me.com \
--cc=boqun.feng@gmail.com \
--cc=linux-kernel@vger.kernel.org \
--cc=longman@redhat.com \
--cc=mingo@redhat.com \
--cc=peterz@infradead.org \
--cc=sxwjean@gmail.com \
--cc=will@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.