On Thu, 17 Mar 2022 02:50:24 -0400 Bibo Mao <maobibo@xxxxxxxxxxx> wrote:
> collapse huge page will copy huge page from general small pages,
> dest node is calculated from most one of source pages, however
> THP daemon is not scheduled on dest node. The performance may be
> poor since huge page copying across nodes, also cache is not used
> for target node. With this patch, khugepaged daemon switches to
> the same numa node with huge page. It saves copying time and makes
> use of local cache better.
>
> With this patch, specint 2006 base performance is improved with 6%
> on Loongson 3C5000L platform with 32 cores and 8 numa nodes.
>
Are there any acks for this one please?
> --- a/mm/khugepaged.c
> +++ b/mm/khugepaged.c
> @@ -1066,6 +1066,7 @@ static void collapse_huge_page(struct mm_struct *mm,
> struct vm_area_struct *vma;
> struct mmu_notifier_range range;
> gfp_t gfp;
> + const struct cpumask *cpumask;
>
> VM_BUG_ON(address & ~HPAGE_PMD_MASK);
>
> @@ -1079,6 +1080,13 @@ static void collapse_huge_page(struct mm_struct *mm,
> * that. We will recheck the vma after taking it again in write mode.
> */
> mmap_read_unlock(mm);
> +
> + /* sched to specified node before huage page memory copy */
> + if (task_node(current) != node) {
> + cpumask = cpumask_of_node(node);
> + if (!cpumask_empty(cpumask))
> + set_cpus_allowed_ptr(current, cpumask);
> + }
> new_page = khugepaged_alloc_page(hpage, gfp, node);
> if (!new_page) {
> result = SCAN_ALLOC_HUGE_PAGE_FAIL;
> --
> 2.31.1
>
