• Peter Zijlstra's avatar
    sched/autogroup: Fix failure to set cpu.rt_runtime_us · 1fe89e1b
    Peter Zijlstra authored
    Because task_group() uses a cache of autogroup_task_group(), whose
    output depends on sched_class, switching classes can generate
    problems.
    
    In particular, when started as fair, the cache points to the
    autogroup, so when switching to RT the tg_rt_schedulable() test fails
    for every cpu.rt_{runtime,period}_us change because now the autogroup
    has tasks and no runtime.
    
    Furthermore, going back to the previous semantics of varying
    task_group() with sched_class has the down-side that the sched_debug
    output varies as well, even though the task really is in the
    autogroup.
    
    Therefore add an autogroup exception to tg_has_rt_tasks() -- such that
    both (all) task_group() usages in sched/core now have one. And remove
    all the remnants of the variable task_group() output.
    Reported-by: default avatarZefan Li <lizefan@huawei.com>
    Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
    Cc: Linus Torvalds <torvalds@linux-foundation.org>
    Cc: Mike Galbraith <umgwanakikbuti@gmail.com>
    Cc: Stefan Bader <stefan.bader@canonical.com>
    Fixes: 8323f26c ("sched: Fix race in task_group()")
    Link: http://lkml.kernel.org/r/20150209112237.GR5029@twins.programming.kicks-ass.netSigned-off-by: default avatarIngo Molnar <mingo@kernel.org>
    1fe89e1b
auto_group.c 5.53 KB