Kernel devs decided not to merge the realtime-lsm patch into the kernel, but
instead came up with a different solution called RTlimits. It was merged into
kernel 2.6.12. PAM support is needed in order to access the functionality.
Steps to Reproduce:
I've tested this patch by adding an epatch line to the 0.78-r2 PAM ebuild. It
built and has been running without any problems. However, the actual ebuild
implementation should probably test the kernel version to make sure it is at
least 2.6.12 before patching.
Created attachment 65456 [details, diff]
PAM Rlimits patch
I am using this patch for my pam since 2005-06-16 (pam-0.78-r2, -r3 and -r4) without any problems.
IMHO it may not even be neccessary to check for kernel versions, because the patch basically adds pam support for the three new limits constants (RLIMIT_NICE, RLIMIT_RTPRIO, RLIM_NLIMITS) and the corresponding config file tokens, but does not change any existing. I would expect the "older" kernels to simply silently ignore LIMITS types they do not support. But of course, do not take my word on this.
Please consider to include it in the official tree, because it is needed to be able to grant realtime privileges to some audio applications (notably JACK, but also others like museseq) for kernels > 2.6.12. Even the most optimized low-latency (or even "soft-RT") kernel is useless if you can not grant applications the right to run at higher priorities anyway ;-)
Hello. From conversations today on the LKML it appears the kernel is moving toward removal of the LSM interface.This will apparently render the emerge of realtime-lsm invalid for some future kernel.
I brought a question up about this on the Linux-Audio-Users mailing list. The consensus there is that PAM 0.99 is required to allow those of us doing realtime audio work to get the same functionality in future kernels.
I would request that a PAM ebuild be put in place for at least pam-0.99 to address this. I do not know yet whether pam-0.99 would then need the patch attached to this bug report. If so I think it should be added with a use flag specific to this sort of feature.
*** This bug has been marked as a duplicate of 87577 ***
JACK user here, hoping for a replacement for realtime-lsm, as my needed audio editing will not be as responsive without this module.