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sched.7: spfix 

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
This commit is contained in:
Michael Kerrisk 2014-05-10 07:22:47 +02:00
parent 81e10454a2
commit 005eaa8f76
1 changed files with 31 additions and 21 deletions
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52
man7/sched.7
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@ -70,12 +70,12 @@ Set the CPU affinity of a specified thread.
.TP
.BR sched_setattr (2)
(Linux-specific)
A generaized API for setting the scheduling policy and parameters
A generalized API for setting the scheduling policy and parameters
of a specified thread.
.TP
.BR sched_getattr (2)
(Linux-specific)
A generaized API for fetching the scheduling policy and parameters
A generalized API for fetching the scheduling policy and parameters
of a specified thread.
.\"
.SS Scheduling policies
@ -238,25 +238,42 @@ or
policies).
.\"
.SS Resetting scheduling policy for child processes
Since Linux 2.6.32, the
.B SCHED_RESET_ON_FORK
flag can be ORed in
.I policy
when calling
.BR sched_setscheduler ().
As a result of including this flag, children created by
Each thread has a reset-on-fork scheduling flag.
When this flag is set, children created by
.BR fork (2)
do not inherit privileged scheduling policies.
This feature is intended for media-playback applications,
The reset-on-fork flag can be set by either:
.IP * 3
ORing the
.B SCHED_RESET_ON_FORK
flag into the
.I policy
argument when calling
.BR sched_setscheduler (2)
(since Linux 2.6.32);
or
.IP *
specifying the
.B SCHED_FLAG_RESET_ON_FORK
flag in
.IR attr.sched_flags
when calling
.BR sched_setattr (2).
.PP
Note that the constants used with these two APIs have different names.
The state of the reset-on-fork flag can analogously be retrieved using
.BR sched_getscheduler (2)
and
.BR sched_getattr (2).
The reset-on-fork feature is intended for media-playback applications,
and can be used to prevent applications evading the
.BR RLIMIT_RTTIME
resource limit (see
.BR getrlimit (2))
by creating multiple child processes.
More precisely, if the
.BR SCHED_RESET_ON_FORK
flag is specified,
More precisely, if the reset-on-fork flag is set,
the following rules apply for subsequently created children:
.IP * 3
If the calling thread has a scheduling policy of
@ -270,19 +287,12 @@ in child processes.
If the calling process has a negative nice value,
the nice value is reset to zero in child processes.
.PP
After the
.BR SCHED_RESET_ON_FORK
flag has been enabled,
After the reset-on-fork flag has been enabled,
it can be reset only if the thread has the
.BR CAP_SYS_NICE
capability.
This flag is disabled in child processes created by
.BR fork (2).
The
.B SCHED_RESET_ON_FORK
flag is visible in the policy value returned by
.BR sched_getscheduler ()
.\"
.SS Privileges and resource limits
In Linux kernels before 2.6.12, only privileged