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Disable multipath cache routing

PATCH pravin b shelar 3 participants 3 messages May 20, 2006 – May 22, 2006 1 message not in the archive

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pravin b shelar

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#1 lore raw
Quoted 7 lines · Chris Wedgwood

Apparently IP_ROUTE_MULTIPATH_CACHED isn't entirely safe to use and will oops the kernel "sooner or later". The Kconfig comment says EXPERIMENTAL but it's not.

Let's go further and mark it BROKEN for now (leaving the comment as-is though). If nobody steps up to resurrect this code we can discuss removing it entirely.

I am working on Linux multipath networking and I will like to fix bugs related to equal cost multipath caching support.

So can u send me following information about the oops :-

kernel version
config file
routing table setup ( any multipath setup information. e.g. multipath algorithm options) iptable configuration
forwarding information
what was the oops message & what triggered that?

This will help me understand the problem.

Thanks & Regards,
Pravin.

#2 lore raw

(cc' list exploded to include various people who might not be reading
netdev, sorry about that)

Quoted 2 lines · pravin b shelar

I am working on Linux multipath networking and I will like to fix bugs related to equal cost multipath caching support.

My experience here is limited to having been using as and finding it was creating erroneous routes which DaveM correctly guessed was the result of CONFIG_IP_MULTIPATH_CACHED being enabled.

Looking over ipv4/route.c there is a fair bit of complex code to audit (fib_semantics.c also needs to be checked, but it's not very involved) so perhaps if you or someone else who understand this code well is interested that would be a good place to start a code audit?

I see also a patch from Herbert Xu about disabling this on the input path (the patch isn't present in the tree right now, I'm not sure if it was revert/fixed or just never merged). Perhaps he can also point out what wrong here?

http://oss.sgi.com/archives/netdev/2005-04/msg00232.html

Anyhow, the code as-is hasn't been maintained for a long time except for a few minor blips (I'm using hg's annotate to find those and have included those people on the cc' list as presumably there are using these features and might have useful input).

#3 lore raw

[CFT] CONFIG_IP_ROUTE_MULTIPATH_CACHED [was Re: [PATCH] Disable multipath cache routing ]

Quoted 5 lines · Chris Wedgwood

...
Anyhow, the code as-is hasn't been maintained for a long time except for a few minor blips (I'm using hg's annotate to find those and have included those people on the cc' list as presumably there are using these features and might have useful input).

We are interested in keeping CONFIG_IP_ROUTE_MULTIPATH_CACHED, as this enables us to do node aware multipathing

	http://lkml.org/lkml/2006/3/22/13

Hence, we are also interested in stabilizing MULTIPATH_CACHED. Please send bug reports with the test case scenario to myself and Pravin at [email protected] and [email protected]

Thanks,
Kiran