Package: runit Version: 1.7.2-1 Severity: normal Hello!
chpst -n seems to always sets the nice value to 19 on x86_64, no
matter what argument has been given:
$ chpst -n 5 ps -l
F S UID PID PPID C PRI NI ADDR SZ WCHAN TTY TIME CMD
0 S 1000 11267 10824 0 75 0 - 2634 - pts/7 00:00:00 bash
0 R 1000 11742 11267 0 97 19 - 1892 - pts/7 00:00:00 ps
On the other hand, chpst works just fine on x86:
[on the x86 box]
$ chpst -n 5 ps -l
F S UID PID PPID C PRI NI ADDR SZ WCHAN TTY TIME CMD
0 S 1000 14282 23386 4 75 0 - 2928 - pts/3 00:00:00 bash
0 R 1000 5586 14282 0 82 5 - 1827 - pts/3 00:00:00 ps
[on the x86_64 box]
$ strace -f chpst -n 5 /bin/true 2>&1 | head -n 5
execve("/usr/bin/chpst", ["chpst", "-n", "5", "/bin/true"], [/* 68 vars */]) = 0
getpriority(PRIO_PROCESS, 0) = 20
setpriority(PRIO_PROCESS, 0, 25) = 0
getpriority(PRIO_PROCESS, 0) = 1
execve("/bin/true", ["/bin/true"], [/* 68 vars */]) = 0
On Linux, "getpriority()" will not return the normal nice-value, but
a negated value that has been offset by 20 (ie it returns 40..1 instead
of -20..19) to avoid negative return values.
On the other hand, "setpriority" accepts _regular_ nice value in the
range -20..19. chpst seems to ignore this difference and sets wrong
nice value as a result.
x86 is not affected since chpst uses "nice" system call here:
[on the x86 box]
$ strace chpst -n 5 /bin/true 2>&1 | head -n 3
execve("/usr/bin/chpst", ["chpst", "-n", "5", "/bin/true"], [/* 67 vars */]) = 0
nice(5) = 0
execve("/bin/true", ["/bin/true"], [/* 67 vars */]) = 0
So I think chpst should either use "nice" system call on x86_64 too
(BTW this should be much faster than getpriority/setpriority variant)
or perform the conversion.
Sorry for not providing the patch (runit source is not exactly
hacker-friendly).
-- System Information:
Debian Release: 4.0
APT prefers testing
APT policy: (500, 'testing')
Architecture: amd64 (x86_64)
Shell: /bin/sh linked to /bin/dash
Kernel: Linux 2.6.17.11-grsec-em64t-p4
Locale: LANG=ru_RU.UTF-8, LC_CTYPE=ru_RU.UTF-8 (charmap=UTF-8)
runit depends on no packages.
Versions of packages runit recommends:
pn fgetty <none> (no description available)
-- no debconf information
--
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