Andrew Morton <[EMAIL PROTECTED]> writes: > On Thu, 7 Feb 2008 14:38:58 +0100 Holger Schurig <[EMAIL PROTECTED]> > wrote: > >> Disable sysctl_check.c for embedded targets. This saves about about 11 kB >> in .text and another 11 kB in .data on a PXA255 embedded platform. >> > > Nice improvement. But iirc sysctl_check was overtly a temporary thing. > Eric, was that the intention?
Well so far sysctl_check has been a remarkably effective little piece of code in catching a great many long over looked bugs. I do agree that the static tables are big. My current inclination is to modify sys_sysctl so that it does a look up in the binary tables to find the ascii names and then sys_sysctl can lookup the information in the ascii tables. If we do that we can completely remove ctl_name form the external sysctl data structures, which should save us quite a bit of space and make it absolutely impossible to add a new binary name. And with the current ability to compile out sys_sysctl the embedded folks would get their space savings. I believe the only tricky bit is there are a few places in the network code where we need to translate from ifindex to interface name. Otherwise the mapping is fixed. No that isn't quite right. Getting the binary to ascii translation for the values is also a bit tricky. As for the rest of the checks I don't know if they are that big. If they are then an option to compile them out on embedded platforms where you know what you are doing makes sense. At the same time sysctl has been so badly abused in the past, and so very many bugs have been over looked that I am extremely reluctant to disable simple sanity checks at registration time. If we can remove the need for sysctl users to implement the binary interface many of those checks go completely away as the reason for their existence would be gone. I have seen to many absolutely horrible things in the usage of the sysctl tables to be happy with an option that removes the sanity checks at this point, although the patch likely makes sense from a code size perspective. Let's see if we can find a bit of time to make those big tables completely specific to sys_sysctl and kill ctl_name in the kernel. Long term that is a whole lot more maintainable, and smaller for everyone who can disable sys_sysctl. Eric -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
