Date: Wed, 18 Jun 2014 13:36:53 +0200 From: Hans Petter Selasky <hps@selasky.org> To: FreeBSD Current <freebsd-current@freebsd.org> Subject: [RFC] Huge sysctl patch for the kernel coming - work in progress Message-ID: <53A179D5.8020604@selasky.org>
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Hi,
Sometimes sysctl's default value needs to be setup at boot time and not
when the rc.d/sysctl is running. Currently this is done by having two
statements in the kernel:
TUNABLE_INT("net.graph.mppe.log_max_rekey", &mppe_log_max_rekey);
SYSCTL_INT(_net_graph_mppe, OID_AUTO, log_max_rekey, CTLFLAG_RW,
I want to simplify this to:
SYSCTL_INT(_net_graph_mppe, OID_AUTO, log_max_rekey, CTLFLAG_RWTUN,
In other words if the existing CTLFLAG_TUN is set, the sysctl will
automatically be pre-loaded with values from /boot/loader.conf.
The reason we don't want the current approach is:
1) It duplicates the sysctl path in the TUNABLE statement.
2) It does not work very well for dynamically attached sysctls. There is
a lot of code overhead computing the TUNABLE() path before the TUNABLE()
can be fetched.
Here is a work in progress:
http://home.selasky.org:8192/sysctl_tunable.diff
In most cases my patch is fine, but in some other cases I need some
input, like in the VM subsystem when doing init, I'm not sure if the
SYSINIT() for subsystem SI_SUB_KMEM, which sysctl's are using, has
already been executed.
--HPS
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