Trying to compile kernel with ck patch & BFQ & Reiser 4. Kernel version is linux-4.4.70-18.9. Error message is:
make[2]: warning: jobserver unavailable: using -j1. Add '+' to parent make rule.
+ make -j2
make[2]: warning: -jN forced in submake: disabling jobserver mode.
kernel/time/tick-sched.c: In function ‘tick_nohz_stop_sched_tick’:
kernel/time/tick-sched.c:587:2: error: implicit declaration of function ‘sched_needs_cpu’ -Werror=implicit-function-declaration]
if (sched_needs_cpu(cpu) || rcu_needs_cpu(basemono, &next_rcu) ||
^
cc1: some warnings being treated as errors
make[4]: *** [kernel/time/tick-sched.o] Error 1
make[3]: *** [kernel/time] Error 2
make[2]: *** [kernel] Error 2
I was compiling kernel in my home dir (copied all files from /usr/src/linux). When I copied .config file from that dir to /usr/src/linux and executed command make -j3 rpm it, suddenly, prints out really useful information about problem & points to the corresponding configuration options! And what I is turned off Old Idle dynticks config (CONFIG_NO_HZ). Why it is so I have no idea. I jut wanted to save some disk space on my root partition.
I’m not sure how an I/O disk scheduler might improve efficiency storing data…
AFAIK the I/O disk scheduler only manages the bytes flow to and from the disk controller to improve throughput which wouldn’t have anything to do with the bytes on the disk.