per-nic module parameters
Subsystems (2)
Hello,
We're working on making myri10ge module parameters per-nic. It looks like ixgb already does so with the following macro in ixgb_param.c:
#define IXGB_PARAM_INIT { [0 ... IXGB_MAX_NIC] = OPTION_UNSET }
#define IXGB_PARAM(X, desc) \
static int __devinitdata X[IXGB_MAX_NIC+1] \
= IXGB_PARAM_INIT; \
static unsigned int num_##X = 0; \
module_param_array_named(X, X, int, &num_##X, 0); \
MODULE_PARM_DESC(X, desc);Is this the recommended way to implement per-nic module params? Or should we do something else?
Thanks,
Brice
Quoted 13 lines · On Fri, 24 Oct 2008 22:09:35 +0200 Brice Goglin <[email protected]> wrote:
Hello,
We're working on making myri10ge module parameters per-nic. It looks like ixgb already does so with the following macro in
ixgb_param.c:#define
IXGB_PARAM_INIT{ [0 ...IXGB_MAX_NIC] =OPTION_UNSET}#define IXGB_PARAM(X, desc) \ static int __devinitdata X[IXGB_MAX_NIC+1] \ = IXGB_PARAM_INIT; \ static unsigned int num_##X = 0; \ module_param_array_named(X, X, int, &num_##X, 0); \ MODULE_PARM_DESC(X, desc);
Quoted 2 lines
Is this the recommended way to implement per-nic module params? Or should we do something else?
Module parameters are bad. They are device specific and awkward for any general configuration system to deal with. As much as possible, please convert any module parameters to real interfaces like netlink, ethtool, or sysfs.
Quoted 16 lines · Stephen Hemminger
Quoted 13 lines · On Fri, 24 Oct 2008 22:09:35 +0200 Brice Goglin <[email protected]> wrote:
Hello,
We're working on making myri10ge module parameters per-nic. It looks like ixgb already does so with the following macro in
ixgb_param.c:#define
IXGB_PARAM_INIT{ [0 ...IXGB_MAX_NIC] =OPTION_UNSET}#define IXGB_PARAM(X, desc) \ static int __devinitdata X[IXGB_MAX_NIC+1] \ = IXGB_PARAM_INIT; \ static unsigned int num_##X = 0; \ module_param_array_named(X, X, int, &num_##X, 0); \ MODULE_PARM_DESC(X, desc);
Quoted 7 lines
Quoted 2 lines
Is this the recommended way to implement per-nic module params? Or should we do something else?
Module parameters are bad. They are device specific and awkward for any general configuration system to deal with. As much as possible, please convert any module parameters to real interfaces like netlink, ethtool, or sysfs.
I agree in principle. However, every distribution uses modutils and allows default module parameters to be set in the same way. So it's easy to tell customers how to configure module parameters persistently. The same cannot be said for ethtool, unfortunately.
Ben.
Signature · 3 lines
Ben Hutchings, Senior Software Engineer, Solarflare Communications Not speaking for my employer; that's the marketing department's job. They asked us to note that Solarflare product names are trademarked.
Quoted 24 lines · Ben Hutchings
Quoted 16 lines · Stephen Hemminger
Quoted 13 lines · On Fri, 24 Oct 2008 22:09:35 +0200 Brice Goglin <[email protected]> wrote:
Hello,
We're working on making myri10ge module parameters per-nic. It looks like ixgb already does so with the following macro in
ixgb_param.c:#define
IXGB_PARAM_INIT{ [0 ...IXGB_MAX_NIC] =OPTION_UNSET}#define IXGB_PARAM(X, desc) \ static int __devinitdata X[IXGB_MAX_NIC+1] \ = IXGB_PARAM_INIT; \ static unsigned int num_##X = 0; \ module_param_array_named(X, X, int, &num_##X, 0); \ MODULE_PARM_DESC(X, desc);Quoted 6 lines
Quoted 2 lines
Is this the recommended way to implement per-nic module params? Or should we do something else?
Module parameters are bad. They are device specific and awkward for any general configuration system to deal with. As much as possible, please convert any module parameters to real interfaces like netlink, ethtool, or sysfs.
Quoted 4 lines
I agree in principle. However, every distribution uses modutils and allows default module parameters to be set in the same way. So it's easy to tell customers how to configure module parameters persistently. The same cannot be said for ethtool, unfortunately.
That makes it a distribution problem, maybe something LSB should address. ixgb inherits this code from e1000, which has been around a very, very long time. It's still a sin that they didn't strip it out when they derived ixgb from e1000, but it's a less severe sin than writing new module parameter code from scratch.
Sometimes there are legitimate reasons to use module parameters, but duplicating ethtool functionality doesn't qualify. Those parameters that e1000 still carries are there because now that they've documented it and customers are using it, they can't ever remove it. Telling your customers to use ETHTOOL_OPTS if their distro has /etc/sysconfig/network-scripts/ifcfg-eth* files, or pre-up if their distro has /etc/network/interfaces is not difficult.
Interface consistency is a worthwhile goal, but you're creating a bigger consistency problem in the kernel than you're solving in the distributions if you do this, and you make it very difficult to ever go back once you realize the mistake.
-- Chris