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From: "David S. Miller" <davem@redhat.com>
To: Krishna Kumar <kumarkr@us.ibm.com>
Cc: kuznet@ms2.inr.ac.ru, mashirle@us.ibm.com, netdev@oss.sgi.com,
	netdev-bounce@oss.sgi.com, xma@us.ibm.com
Subject: Re: [PATCH]snmp6 64-bit counter support in proc.c
Date: Thu, 22 Jan 2004 14:10:26 -0800	[thread overview]
Message-ID: <20040122141026.6a728abe.davem@redhat.com> (raw)
In-Reply-To: <OFBED1B971.06995FF1-ON88256E23.006E3E55@us.ibm.com>


The most portable and simple algorithm to solve this on the reader
side is (and I recommend we don't special case this on 64-bit platforms
just to get wider testing):

	u32 high, low1, low2;

	do {
		low1 = stat & 0xffffffff;
		rmb();
		high = stat >> 32;
		rmb();
		low2 = stat & 0xffffffff;
	} while (low2 < low1);

Something like that.  The idea is to sample the lower 32-bit twice
and if it overflows resample both high and low halfs.

  reply	other threads:[~2004-01-22 22:10 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-01-22 21:18 [PATCH]snmp6 64-bit counter support in proc.c Krishna Kumar
2004-01-22 22:10 ` David S. Miller [this message]
  -- strict thread matches above, loose matches on Subject: below --
2004-01-28 20:15 Shirley Ma
2004-01-28 20:09 Shirley Ma
2004-01-28 19:19 Krishna Kumar
2004-01-28 19:33 ` David S. Miller
2004-01-23 18:06 Shirley Ma
2004-01-23  2:57 Krishna Kumar
2004-01-23  2:45 Krishna Kumar
2004-01-28 19:09 ` David S. Miller
2004-01-23  1:08 Shirley Ma
2004-01-23  1:43 ` David S. Miller
2004-01-22 22:50 Krishna Kumar
2004-01-23  0:35 ` David S. Miller
2004-01-21 23:44 Shirley Ma
2004-01-21 19:45 Shirley Ma
2004-01-21 20:27 ` YOSHIFUJI Hideaki / 吉藤英明
2004-01-21 22:05 ` David S. Miller
2004-01-22 18:26 ` kuznet
2003-12-05 21:55 Shirley Ma
2003-12-02 12:40 IPv6 MIB:ipv6PrefixTable implementation kuznet
2003-12-05 20:14 ` [PATCH]snmp6 64-bit counter support in proc.c Shirley Ma
2003-12-05 20:31   ` David S. Miller
2004-01-14 22:52     ` Shirley Ma
2004-01-15  8:57       ` David S. Miller

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