From: Con Kolivas Alterations to the pipe code in the kernel made it possible for relative starvation to occur with tasks that slept waiting on a pipe getting unfair priority bonuses even if they were otherwise fully cpu bound so the TASK_NONINTERACTIVE flag was introduced which prevented any change to sleep_avg while sleeping waiting on a pipe. This change also leads to the converse though, preventing any priority boost from occurring in truly interactive tasks that wait on pipes. Convert the TASK_NONINTERACTIVE flag to set sleep_type to SLEEP_NONINTERACTIVE which will allow a linear bonus to priority based on sleep time thus allowing interactive tasks to get high priority if they sleep enough. Signed-off-by: Con Kolivas Acked-by: Ingo Molnar Signed-off-by: Andrew Morton --- kernel/sched.c | 16 ++++++++-------- 1 files changed, 8 insertions(+), 8 deletions(-) diff -puN kernel/sched.c~sched-make_task_noninteractive_use_sleep_type kernel/sched.c --- devel/kernel/sched.c~sched-make_task_noninteractive_use_sleep_type 2006-01-13 20:52:10.000000000 -0800 +++ devel-akpm/kernel/sched.c 2006-01-13 20:52:10.000000000 -0800 @@ -1366,18 +1366,18 @@ out_activate: * cpu bound so label them as noninteractive. */ p->sleep_type = SLEEP_NONINTERACTIVE; - } + } else /* * Tasks that have marked their sleep as noninteractive get - * woken up without updating their sleep average. (i.e. their - * sleep is handled in a priority-neutral manner, no priority - * boost and no penalty.) + * woken up with their sleep average not weighted in an + * interactive way. */ - if (old_state & TASK_NONINTERACTIVE) - __activate_task(p, rq); - else - activate_task(p, rq, cpu == this_cpu); + if (old_state & TASK_NONINTERACTIVE) + p->sleep_type = SLEEP_NONINTERACTIVE; + + + activate_task(p, rq, cpu == this_cpu); /* * Sync wakeups (i.e. those types of wakeups where the waker * has indicated that it will leave the CPU in short order) _