Re: [PATCH] mm: set hugepage to false when anon mthp allocation

[Kefeng Wang <wangkefeng.wang@huawei.com>]

On 2024/9/10 22:06, Kefeng Wang wrote:
> When the hugepage parameter is true in vma_alloc_folio(), it indicates
> that we only try allocation on preferred node if possible for PMD_ORDER,

Should remove "for PMD_ORDER", I mean that it was used for PMD_ORDER, 
but for other high-order, it will reduce the success rate of allocation 
if without ddc1a5cbc05d.


> but it could lead to lots of failures for large folio allocation,
> luckily the hugepage parameter was deprecated since commit ddc1a5cbc05d
> ("mempolicy: alloc_pages_mpol() for NUMA policy without vma"), so no
> effect on runtime behavior.
> 
> Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
> ---
> 
> Found the issue when backport mthp to inner kernel without ddc1a5cbc05d,
> but for mainline, there is no issue, no clue why hugepage parameter was
> retained, maybe just kill the parameter for mainline?
> 
>   mm/memory.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/mm/memory.c b/mm/memory.c
> index b84443e689a8..89a15858348a 100644
> --- a/mm/memory.c
> +++ b/mm/memory.c
> @@ -4479,7 +4479,7 @@ static struct folio *alloc_anon_folio(struct vm_fault *vmf)
>   	gfp = vma_thp_gfp_mask(vma);
>   	while (orders) {
>   		addr = ALIGN_DOWN(vmf->address, PAGE_SIZE << order);
> -		folio = vma_alloc_folio(gfp, order, vma, addr, true);
> +		folio = vma_alloc_folio(gfp, order, vma, addr, false);
>   		if (folio) {
>   			if (mem_cgroup_charge(folio, vma->vm_mm, gfp)) {
>   				count_mthp_stat(order, MTHP_STAT_ANON_FAULT_FALLBACK_CHARGE);