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From: Robin Holt <holt@sgi.com>
To: "David S. Miller" <davem@davemloft.net>,
	Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>,
	"Pekka Savola (ipv6)" <pekkas@netcore.fi>,
	James Morris <jmorris@namei.org>,
	Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>,
	Patrick McHardy <kaber@trash.net>,
	Vlad Yasevich <vladislav.yasevich@hp.com>,
	Sridhar Samudrala <sri@us.ibm.com>
Cc: linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
	linux-decnet-user@lists.sourceforge.net,
	linux-sctp@vger.kernel.org
Subject: sysctl_{tcp,udp,sctp}_mem overflow on 16TB system.
Date: Fri, 01 Oct 2010 19:39:58 +0000	[thread overview]
Message-ID: <20101001193958.GP14068@sgi.com> (raw)


On a 16TB system, we noticed that sysctl_tcp_mem[2] and sysctl_udp_mem[2]
were negative.  Code review indicates that the same should occur with
sysctl_sctp_mem[2].

There are a couple ways we could address this.  The one which appears most
reasonable would be to change the struct proto defintion for sysctl_mem
from an int to a long and handle all the associated fallout.

An alternative is to limit the calculation to 1/2 INT_MAX.  The downside
being that the administrator could not tune the system to use more than
INT_MAX memory when much more is available.

Is there a compelling reason to not change the structure's definition
over to longs instead of ints and deal with the fallout from that change?

Thanks,
Robin Holt

WARNING: multiple messages have this Message-ID (diff)
From: Robin Holt <holt@sgi.com>
To: "David S. Miller" <davem@davemloft.net>,
	Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>,
	"Pekka Savola (ipv6)" <pekkas@netcore.fi>,
	James Morris <jmorris@namei.org>,
	Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>,
	Patrick McHardy <kaber@trash.net>,
	Vlad Yasevich <vladislav.yasevich@hp.com>,
	Sridhar Samudrala <sri@us.ibm.com>
Cc: linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
	linux-decnet-user@lists.sourceforge.net,
	linux-sctp@vger.kernel.org
Subject: sysctl_{tcp,udp,sctp}_mem overflow on 16TB system.
Date: Fri, 1 Oct 2010 14:39:58 -0500	[thread overview]
Message-ID: <20101001193958.GP14068@sgi.com> (raw)


On a 16TB system, we noticed that sysctl_tcp_mem[2] and sysctl_udp_mem[2]
were negative.  Code review indicates that the same should occur with
sysctl_sctp_mem[2].

There are a couple ways we could address this.  The one which appears most
reasonable would be to change the struct proto defintion for sysctl_mem
from an int to a long and handle all the associated fallout.

An alternative is to limit the calculation to 1/2 INT_MAX.  The downside
being that the administrator could not tune the system to use more than
INT_MAX memory when much more is available.

Is there a compelling reason to not change the structure's definition
over to longs instead of ints and deal with the fallout from that change?

Thanks,
Robin Holt

WARNING: multiple messages have this Message-ID (diff)
From: Robin Holt <holt@sgi.com>
To: "David S. Miller" <davem@davemloft.net>,
	Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>,
	"Pekka Savola (ipv6)" <pekkas@netcore.fi>,
	James Morris <jmorris@namei.org>,
	Hideaki YOSHIFUJI <yosh
Cc: linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
	linux-decnet-user@lists.sourceforge.net,
	linux-sctp@vger.kernel.org
Subject: sysctl_{tcp,udp,sctp}_mem overflow on 16TB system.
Date: Fri, 1 Oct 2010 14:39:58 -0500	[thread overview]
Message-ID: <20101001193958.GP14068@sgi.com> (raw)


On a 16TB system, we noticed that sysctl_tcp_mem[2] and sysctl_udp_mem[2]
were negative.  Code review indicates that the same should occur with
sysctl_sctp_mem[2].

There are a couple ways we could address this.  The one which appears most
reasonable would be to change the struct proto defintion for sysctl_mem
from an int to a long and handle all the associated fallout.

An alternative is to limit the calculation to 1/2 INT_MAX.  The downside
being that the administrator could not tune the system to use more than
INT_MAX memory when much more is available.

Is there a compelling reason to not change the structure's definition
over to longs instead of ints and deal with the fallout from that change?

Thanks,
Robin Holt

             reply	other threads:[~2010-10-01 19:39 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-10-01 19:39 Robin Holt [this message]
2010-10-01 19:39 ` sysctl_{tcp,udp,sctp}_mem overflow on 16TB system Robin Holt
2010-10-01 19:39 ` Robin Holt
2010-10-01 20:30 ` Willy Tarreau
2010-10-01 20:30   ` Willy Tarreau
2010-10-03  8:20   ` Maciej Żenczykowski
2010-10-03  8:20     ` Maciej Żenczykowski
2010-10-03 11:54     ` Robin Holt
2010-10-03 11:54       ` Robin Holt
2010-10-03 16:43     ` Willy Tarreau
2010-10-03 16:43       ` Willy Tarreau

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