From: Eric Dumazet <eric.dumazet@gmail.com>
To: Hong Zhiguo <honkiko@gmail.com>
Cc: netdev@vger.kernel.org, davem@davemloft.net,
stephen@networkplumber.org, Hong Zhiguo <zhiguohong@tencent.com>
Subject: Re: [PATCH net-next] gen_estimator: change the lock order for better perfermance
Date: Tue, 17 Sep 2013 04:11:48 -0700 [thread overview]
Message-ID: <1379416308.29845.11.camel@edumazet-glaptop> (raw)
In-Reply-To: <1379407101-18933-1-git-send-email-zhiguohong@tencent.com>
On Tue, 2013-09-17 at 16:38 +0800, Hong Zhiguo wrote:
> From: Hong Zhiguo <zhiguohong@tencent.com>
>
> e->stats_lock is usually taken by fast path to update stats.
> In the old order, fast path should wait for write_lock(&est_lock).
> Even though it's only one line inside the write_lock(&est_lock),
> but if there's interrupt or page fault, a lot of spin on
> e->stats_lock will be wasted in fast path.
1) net-next is not open
2) There is no way a page fault can happen in this path.
3) This patch is wrong.
Current order is there for good reasons.
Have you really tried LOCKDEP, before sending a patch changing lock
order ?
next prev parent reply other threads:[~2013-09-17 11:11 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-17 8:38 [PATCH net-next] gen_estimator: change the lock order for better perfermance Hong Zhiguo
2013-09-17 11:11 ` Eric Dumazet [this message]
2013-09-18 5:41 ` 答复: [PATCH net-next] gen_estimator: change the lock order for better perfermance(Internet mail) zhiguohong(洪志国)
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