Date: Tue, 14 Feb 2012 12:37:55 +0100 From: Alexander Leidinger <Alexander@Leidinger.net> To: freebsd-stable@freebsd.org Subject: Custom kernel poll summary (was: Re: Reducing the need to compile a custom kernel) Message-ID: <20120214123755.Horde.WkLNcJjmRSRPOkeTw7bUClA@webmail.leidinger.net> In-Reply-To: <20120210145604.Horde.ewjpSpjmRSRPNSH0YRHxgAk@webmail.leidinger.net> References: <20120210145604.Horde.ewjpSpjmRSRPNSH0YRHxgAk@webmail.leidinger.net>
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Quoting Alexander Leidinger <Alexander@Leidinger.net> (from Fri, 10
Feb 2012 14:56:04 +0100):
> Such a kernel would cover situations where people compile their own
> kernel because they want to get rid of some unused kernel code (and
> maybe even need the memory this frees up).
>
> The question is, is this enough? Or asked differently, why are you
> compiling a custom kernel in a production environment (so I rule out
> debug options zhich are not enabled in GENERIC)? Are there options
> which you add which you can not add as a module (SW_WATCHDOG comes
> to my mind)? If yes, which ones and how important are they for you?
Here is what I got, the first column is the number of requests, the
second what is requested, and the 3rd my comments (basically it means,
if there is a comment, it is not needed/possible to include in a
modular kernel):
---snip---
5 IPSEC
4 ALTQ
2 VIMAGE -> not production ready (bz)
2 SW_WATCHDOG
2 IPSEC_FILTERTUNNEL -> obsolete according to bz
2 IPFIREWALL_DEFAULT_TO_ACCEPT -> loader.conf:
net.inet.ip.fw.default_to_accept
2 IPFIREWALL -> loader.conf: ipfw_load='YES'
2 HZ=1000 -> loader.conf: kern.hz
2 DEVICE_POLLING -> ifconfig in 9.0 handles this at runtime?
1 enc
1 ZERO_COPY_SOCKETS -> has known problems? can't find the
reference,
but I removed it from my kernels
1 SC_* options -> not a generic setting, will not include
1 ROUTETABLES=n -> bz is working on this
1 QUOTA
1 PF -> loader.conf: pf_load='YES'
1 MROUTING -> loader.conf: ip_mroute='YES'?
1 KTR -> rare use case, kernel recompile is OK
1 KDTRACE_HOOKS -> legal review needed
1 KDB_UNATTENDED -> re@ wants this, but has reservations
1 KDB_TRACE -> re@ wants this, but has reservations
1 KDB -> re@ wants this, but has reservations
1 IPSTEALTH
1 IPSEC_NAT_T
1 IPFIREWALL_VERBOSE_LIMIT=5
1 IPFIREWALL_VERBOSE
1 IPFIREWALL_FORWARD -> performance impact too big if
unused (julian)
1 IPFILTER -> 2/3 firewalls can be loaded... and this one
is not really maintained anymore
1 IPDIVERT -> loader.conf: ipdivert_load='YES'
1 GDB
1 FLOWTABLE
1 DUMMYNET -> loader.conf: dummynet_load='YES'
1 DIRECTIO
1 DDB_NUMSYM
1 DDB
1 BREAK_TO_DEBUGGER -> loader.conf: debug.kdb.break_to_debugger
1 BPF_JITTER
1 ALT_BREAK_TO_DEBUGGER -> loader.conf:
debug.kdb.alt_break_to_debugger
---snip---
Yes, this poll is not representative...
So... what's the impact of including the following options into a
kernel which is intended to be modular, respectively are there reasons
to _not_ include one of the following?
---snip---
5 IPSEC -> we do not have a separate cryto
dist, so it should be possible
to include in a kernel now...
legal advise needed
4 ALTQ* -> does add code to the pf module
other impact?
2 SW_WATCHDOG -> should not hurt if not enabled
in rc.conf
1 enc -> together with IPSEC
1 IPSTEALTH -> changes ipfw module only?
1 IPSEC_NAT_T
1 IPFIREWALL_VERBOSE_LIMIT=5 -> changes ipfw module only?
loader tunable?
1 IPFIREWALL_VERBOSE -> changes ipfw module only?
loader tunable?
1 FLOWTABLE
1 DIRECTIO
1 BPF_JITTER
---snip---
Bye,
Alexander.
--
Q: What is purple and concord the world?
A: Alexander the Grape.
http://www.Leidinger.net Alexander @ Leidinger.net: PGP ID = B0063FE7
http://www.FreeBSD.org netchild @ FreeBSD.org : PGP ID = 72077137
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