Messages in this thread | | | Subject | Re: [PATCH 6/6] cls_cgroup: remove redundant rcu_read_lock/unlock | From | Eric Dumazet <> | Date | Wed, 01 Feb 2012 08:07:19 +0100 |
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Le mercredi 01 février 2012 à 14:56 +0800, Li Zefan a écrit : > We've already used rcu_read_lock/unlock inside task_classid(), > so don't use the lock/unlock pair twice in this hot path. > > Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> > --- > net/core/sock.c | 2 -- > 1 files changed, 0 insertions(+), 2 deletions(-) > > diff --git a/net/core/sock.c b/net/core/sock.c > index 213c856..c0bab23 100644 > --- a/net/core/sock.c > +++ b/net/core/sock.c > @@ -1160,9 +1160,7 @@ void sock_update_classid(struct sock *sk) > { > u32 classid; > > - rcu_read_lock(); /* doing current task, which cannot vanish. */ > classid = task_cls_classid(current); > - rcu_read_unlock(); > if (classid && classid != sk->sk_classid) > sk->sk_classid = classid;
Yes, this seems fine.
Then, I wonder why we do the "if (classid && classid != sk->sk_classid)"
before the :
sk->sk_classid = classid;
This seems unnecessary checks.
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