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From: David Miller <davem-fT/PcQaiUtIeIZ0/mPfg9Q@public.gmane.org>
To: eric.dumazet-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org
Cc: lizf-BthXqXjhjHXQFUHtdCDX3A@public.gmane.org,
	netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	nhorman-2XuSBdqkA4R54TAoqtyWWQ@public.gmane.org
Subject: Re: [PATCH 6/6] cls_cgroup: remove redundant rcu_read_lock/unlock
Date: Wed, 01 Feb 2012 02:10:02 -0500 (EST)	[thread overview]
Message-ID: <20120201.021002.1399660597996401402.davem@davemloft.net> (raw)
In-Reply-To: <1328080039.22641.2.camel@edumazet-laptop>

From: Eric Dumazet <eric.dumazet-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Date: Wed, 01 Feb 2012 08:07:19 +0100

> Then, I wonder why we do the "if (classid && classid != sk->sk_classid)"
> 
> before the :
> 
> 	sk->sk_classid = classid;
> 
> This seems unnecessary checks.
> 

Avoiding dirtying the sk->sk_classid cache line unnecessarily?

I actually have no idea actually how often this routine can get
invoked in real world scenerios.

  reply	other threads:[~2012-02-01  7:10 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-02-01  6:55 [PATCH 1/6] netprio_cgroup: fix an off-by-one bug Li Zefan
2012-02-01  6:55 ` [PATCH 3/6] netprio_cgroup: fix wrong memory access when NETPRIO_CGROUP=m Li Zefan
2012-02-01  6:56 ` [PATCH 4/6] netprio_cgroup: use IS_ENABLED() and family Li Zefan
     [not found]   ` <4F28E203.10502-BthXqXjhjHXQFUHtdCDX3A@public.gmane.org>
2012-02-01  6:59     ` David Miller
     [not found]       ` <20120201.015954.2098592611164231843.davem-fT/PcQaiUtIeIZ0/mPfg9Q@public.gmane.org>
2012-02-01  7:06         ` Li Zefan
     [not found]           ` <4F28E48D.3040505-BthXqXjhjHXQFUHtdCDX3A@public.gmane.org>
2012-02-01  7:07             ` David Miller
2012-02-01  7:22               ` Li Zefan
     [not found]                 ` <4F28E853.7000104-BthXqXjhjHXQFUHtdCDX3A@public.gmane.org>
2012-02-01 12:02                   ` Neil Horman
     [not found] ` <4F28E1D1.900-BthXqXjhjHXQFUHtdCDX3A@public.gmane.org>
2012-02-01  6:55   ` [PATCH 2/6] netprio_cgroup: don't allocate prio table when a device is registered Li Zefan
2012-02-01  6:56   ` [PATCH 5/6] cls_cgroup: use IS_ENABLED() and family Li Zefan
2012-02-01  6:56 ` [PATCH 6/6] cls_cgroup: remove redundant rcu_read_lock/unlock Li Zefan
     [not found]   ` <4F28E22A.703-BthXqXjhjHXQFUHtdCDX3A@public.gmane.org>
2012-02-01  7:07     ` Eric Dumazet
2012-02-01  7:10       ` David Miller [this message]
2012-02-01  7:20       ` Li Zefan
     [not found]         ` <4F28E7A0.6000309-BthXqXjhjHXQFUHtdCDX3A@public.gmane.org>
2012-02-01  7:23           ` Herbert Xu

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