diff options
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/sched/fair.c | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 7072de1686d5..ef27b5931480 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -2928,6 +2928,21 @@ static void reset_ptenuma_scan(struct task_struct *p) p->mm->numa_scan_offset = 0; } +static bool vma_is_accessed(struct vm_area_struct *vma) +{ + /* + * Allow unconditional access first two times, so that all the (pages) + * of VMAs get prot_none fault introduced irrespective of accesses. + * This is also done to avoid any side effect of task scanning + * amplifying the unfairness of disjoint set of VMAs' access. + */ + if (READ_ONCE(current->mm->numa_scan_seq) < 2) + return true; + + return test_bit(current->pid % BITS_PER_LONG, + &vma->numab_state->access_pids); +} + /* * The expensive part of numa migration is done from task_work context. * Triggered from task_tick_numa(). @@ -3046,6 +3061,10 @@ static void task_numa_work(struct callback_head *work) vma->numab_state->next_scan)) continue; + /* Do not scan the VMA if task has not accessed */ + if (!vma_is_accessed(vma)) + continue; + do { start = max(start, vma->vm_start); end = ALIGN(start + (pages << PAGE_SHIFT), HPAGE_SIZE); |