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

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

Hi All,

On 2024/9/10 22:18, Kefeng Wang wrote:
> 
> 
> 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?


Any comments, fix in alloc_anon_folio() or remove hugepage parameter in 
vma_alloc_folio(), thanks.

>>
>>   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);
>