Messages in this thread | | | Date | Tue, 25 Apr 2006 12:37:35 +1000 | From | Peter Williams <> | Subject | Re: [PATCH] sched: Fix boolean expression in move_tasks() |
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Andrew Morton wrote: > Peter Williams <pwil3058@bigpond.net.au> wrote: >> Negate the expression and apply de Marcos rule to simplify it. This >> patch is on top of >> sched-avoid-unnecessarily-moving-highest-priority-task-move_tasks.patch >> >> Signed-off-by: Peter Williams <pwil3058@bigpond.com.au> >> >> -- >> Peter Williams pwil3058@bigpond.net.au >> >> "Learning, n. The kind of ignorance distinguishing the studious." >> -- Ambrose Bierce >> >> >> [smpnice-fix-boolean-expression text/plain (824 bytes)] >> Index: MM-2.6.17-rc1-mm3/kernel/sched.c >> =================================================================== >> --- MM-2.6.17-rc1-mm3.orig/kernel/sched.c 2006-04-21 12:26:54.000000000 +1000 >> +++ MM-2.6.17-rc1-mm3/kernel/sched.c 2006-04-25 09:09:54.000000000 +1000 >> @@ -2108,7 +2108,7 @@ skip_queue: >> */ >> skip_for_load = tmp->load_weight > rem_load_move; >> if (skip_for_load && idx < this_best_prio) >> - skip_for_load = busiest_best_prio_seen || idx != busiest_best_prio; >> + skip_for_load = !busiest_best_prio_seen && idx == busiest_best_prio; > > But Suresh's > sched-avoid-unnecessarily-moving-highest-priority-task-move_tasks-fix.patch > changed all this code: > > /* > * To help distribute high priority tasks accross CPUs we don't > * skip a task if it will be the highest priority task (i.e. smallest > * prio value) on its new queue regardless of its load weight > */ > skip_for_load = tmp->load_weight > rem_load_move; > if (skip_for_load && idx < this_best_prio && idx == busiest_best_prio) > skip_for_load = !busiest_best_prio_seen && > head->next == head->prev; > if (skip_for_load || > !can_migrate_task(tmp, busiest, this_cpu, sd, idle, &pinned)) { > if (curr != head) > goto skip_queue; > idx++; > goto skip_bitmap; > } > > > What to do?
Suresh's patch was wrong and this was intended as an alternative. Unfortunately, it is also in adequate and the setting of busiest_best_prio_seen needs to be moved to just after skip_for_load is set. I have another patch that does that (and adds to the comments). Should I send that separately or roll the two patches together?
Peter -- Peter Williams pwil3058@bigpond.net.au
"Learning, n. The kind of ignorance distinguishing the studious." -- Ambrose Bierce - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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