Messages in this thread | | | Subject | Re: [PATCH 22/23] sysctl arm: Remove binary sysctl support | From | (Eric W. Biederman) | Date | Sun, 08 Nov 2009 19:27:07 -0800 |
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Arjan van de Ven <arjan@infradead.org> writes:
> On Sun, 08 Nov 2009 15:05:05 -0800 > ebiederm@xmission.com (Eric W. Biederman) wrote: > >> > >> > The practical difference is that /proc support now must be compiled >> > in to support sys_sysctl. >> >> But thanks for the reminder that I need to go into glibc and fix this >> before we disable the sys_sysctl emulation by default. > > how are you dealing with existing glibcs ? Or with static linked > binaries? or.. or .. > > breaking a heavily used ABI like this is not going to be pretty > or even sane, no matter which way you hate the current one.
sysctl_binary.c has all of the code to continue to provide the existing ABI.
sys_sysctl is not heavily used at all, and this is the responsible removal of a practically unused ABI. Last I check (and this was before I shouted to the world that sys_sysctl is going away) I could count on one hand all of the users of sys_sysctl.
/proc/sys will definitely continue to exist.
I just took a look and the use in linux threads that I don't warn about is used by glibc-2.8 but not by glibc-2.10. glibc-2.11 has just been released. so by next year when the removal is scheduled we are looking at multiple releases of glibc that don't use sys_sysctl. So I expect shortly I can warn about all uses of sys_sysctl without anyone seeing a warning.
The one unfixed case I know about is fixing ioperm on arm, in the glibc ports tree, and that will need to happen before sys_sysctl is disabled by default. Which is all I intend to do when we reach that point in feature removal schedule now that I have refactored the code so that sys_sysctl no longer imposes a maintenance burden on the sane sysctl users.
I don't hate sysctl, in fact for global tuneables I would argue for all it's faults sysctl it is one of the better interfaces we have. I just figure the implementation needs to be optimized for the way sysctl is used today, the via /proc/sys.
Eric
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