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From: Eric Dumazet <dada1@cosmosbay.com>
To: "David S. Miller" <davem@davemloft.net>
Cc: netdev@vger.kernel.org
Subject: [PATCH] [NET] can use __get_cpu_var() instead of per_cpu() in loopback driver
Date: Fri, 20 Oct 2006 09:18:35 +0200	[thread overview]
Message-ID: <4538784B.2000306@cosmosbay.com> (raw)
In-Reply-To: <4535B6B7.4070107@cosmosbay.com>

[-- Attachment #1: Type: text/plain, Size: 220 bytes --]

As BHs are off in loopback_xmit(), preemption cannot occurs, so we can use 
__get_cpu_var() instead of per_cpu() (and avoid a 
preempt_enable()/preempt_disable() pair)

Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>


[-- Attachment #2: loopback.patch --]
[-- Type: text/plain, Size: 522 bytes --]

--- net-2.6/drivers/net/loopback.c	2006-10-19 16:46:27.000000000 +0200
+++ net-2.6-ed/drivers/net/loopback.c      2006-10-20 09:11:04.000000000 +0200
@@ -153,14 +153,14 @@
 #endif
 	dev->last_rx = jiffies;
 
-	lb_stats = &per_cpu(pcpu_lstats, get_cpu());
+	/* it's OK to use __get_cpu_var() because BHs are off */
+	lb_stats = &__get_cpu_var(pcpu_lstats);
 	lb_stats->bytes += skb->len;
 	lb_stats->packets++;
-	put_cpu();
 
 	netif_rx(skb);
 
-	return(0);
+	return 0;
 }
 
 static struct net_device_stats loopback_stats;

  parent reply	other threads:[~2006-10-20  7:27 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20051217071029.GY23384@wotan.suse.de>
     [not found] ` <20051216.231517.68922847.davem@davemloft.net>
     [not found]   ` <43A3EE8A.5020907@cosmosbay.com>
     [not found]     ` <43CCBF3D.2070900@cosmosbay.com>
     [not found]       ` <4415A4C1.1030906@cosmosbay.com>
2006-10-12 20:14         ` [PATCH] [NET] reduce sizeof(struct inet_peer), cleanup, change in peer_check_expire() Eric Dumazet
2006-10-12 22:15           ` David Miller
2006-10-13  3:56             ` Eric Dumazet
2006-10-13  4:18               ` David Miller
2006-10-13  4:24                 ` Eric Dumazet
2006-10-18  5:08           ` [PATCH] [NET] reduce sizeof(struct flow) Eric Dumazet
2006-10-18  5:17             ` YOSHIFUJI Hideaki / 吉藤英明
2006-10-18  5:30               ` Eric Dumazet
2006-10-18  5:27             ` David Miller
2006-10-18  5:42               ` Eric Dumazet
2006-10-18  6:53                 ` David Miller
2006-10-18  8:20                   ` Steven Whitehouse
2006-10-18  8:55                     ` Eric Dumazet
2006-10-18 12:42                       ` Steven Whitehouse
2006-10-18 13:32                         ` Eric Dumazet
2006-10-19  3:50                           ` David Miller
2006-10-19  5:13                             ` Eric Dumazet
2006-10-20 13:55                         ` [PATCH] [NET] reduce sizeof(struct flowi) by 20 bytes Eric Dumazet
2006-10-22  3:25                           ` David Miller
2006-10-18 11:33               ` [PATCH] [NET] reduce sizeof(struct flow) Ingo Oeser
2006-10-20  7:18             ` Eric Dumazet [this message]
2006-10-20  7:32               ` [PATCH] [NET] can use __get_cpu_var() instead of per_cpu() in loopback driver David Miller

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