From: Valentin Schneider Date: Mon, 15 Jul 2019 10:25:07 +0000 (+0100) Subject: sched/fair: Move task_numa_work() init to init_numa_balancing() X-Git-Tag: v5.4-rc1~176^2~44 X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=b34920d4ce6e6fc9424c20a4be98676eb543122f;p=linux.git sched/fair: Move task_numa_work() init to init_numa_balancing() We only need to set the callback_head worker function once, do it during sched_fork(). While at it, move the comment regarding double task_work addition to init_numa_balancing(), since the double add sentinel is first set there. Suggested-by: Peter Zijlstra Signed-off-by: Valentin Schneider Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Thomas Gleixner Cc: mgorman@suse.de Cc: riel@surriel.com Link: https://lkml.kernel.org/r/20190715102508.32434-3-valentin.schneider@arm.com Signed-off-by: Ingo Molnar --- diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index f0c488015649..fd391fc00ed8 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -2495,7 +2495,7 @@ void task_numa_work(struct callback_head *work) SCHED_WARN_ON(p != container_of(work, struct task_struct, numa_work)); - work->next = work; /* protect against double add */ + work->next = work; /* * Who cares about NUMA placement when they're dying. * @@ -2639,12 +2639,15 @@ void init_numa_balancing(unsigned long clone_flags, struct task_struct *p) p->node_stamp = 0; p->numa_scan_seq = mm ? mm->numa_scan_seq : 0; p->numa_scan_period = sysctl_numa_balancing_scan_delay; + /* Protect against double add, see task_tick_numa and task_numa_work */ p->numa_work.next = &p->numa_work; p->numa_faults = NULL; RCU_INIT_POINTER(p->numa_group, NULL); p->last_task_numa_placement = 0; p->last_sum_exec_runtime = 0; + init_task_work(&p->numa_work, task_numa_work); + /* New address space, reset the preferred nid */ if (!(clone_flags & CLONE_VM)) { p->numa_preferred_nid = NUMA_NO_NODE; @@ -2693,10 +2696,8 @@ static void task_tick_numa(struct rq *rq, struct task_struct *curr) curr->numa_scan_period = task_scan_start(curr); curr->node_stamp += period; - if (!time_before(jiffies, curr->mm->numa_next_scan)) { - init_task_work(work, task_numa_work); /* TODO: move this into sched_fork() */ + if (!time_before(jiffies, curr->mm->numa_next_scan)) task_work_add(curr, work, true); - } } }