Re: [PATCH] mm: add more readable thp_vma_allowable_order_foo()

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

On 2024/4/24 22:05, Ryan Roberts wrote:
> On 24/04/2024 15:07, Kefeng Wang wrote:
>> There are too many bool arguments in thp_vma_allowable_orders(), adding
>> some more readable thp_vma_allowable_order_foo(),
>>
>>    thp_vma_allowable_orders_insmaps() is used in samps
>>    thp_vma_allowable_order[s]_inpf()  is used in page fault
>>    thp_vma_allowable_pmd_order_inhuge is used in khugepaged scan and madvise
>>
>> Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
> 
> Just one nit below. With that addressed:
> 
> Reviewed-by: Ryan Roberts <ryan.roberts@arm.com>
> 
>> ---
>>   fs/proc/task_mmu.c      |  3 +--
>>   include/linux/huge_mm.h | 14 ++++++++++++--
>>   mm/khugepaged.c         | 20 ++++++++------------
>>   mm/memory.c             |  8 ++++----
>>   4 files changed, 25 insertions(+), 20 deletions(-)
>>
>> diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
>> index f4259b7edfde..1136aa97f143 100644
>> --- a/fs/proc/task_mmu.c
>> +++ b/fs/proc/task_mmu.c
>> @@ -871,8 +871,7 @@ static int show_smap(struct seq_file *m, void *v)
>>   	__show_smap(m, &mss, false);
>>   
>>   	seq_printf(m, "THPeligible:    %8u\n",
>> -		   !!thp_vma_allowable_orders(vma, vma->vm_flags, true, false,
>> -					      true, THP_ORDERS_ALL));
>> +		   thp_vma_allowable_orders_insmaps(vma, vma->vm_flags));
>>   
>>   	if (arch_pkeys_enabled())
>>   		seq_printf(m, "ProtectionKey:  %8u\n", vma_pkey(vma));
>> diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
>> index 56c7ea73090b..345cf394480b 100644
>> --- a/include/linux/huge_mm.h
>> +++ b/include/linux/huge_mm.h
>> @@ -83,8 +83,18 @@ extern struct kobj_attribute shmem_enabled_attr;
>>    */
>>   #define THP_ORDERS_ALL		(THP_ORDERS_ALL_ANON | THP_ORDERS_ALL_FILE)
>>   
>> -#define thp_vma_allowable_order(vma, vm_flags, smaps, in_pf, enforce_sysfs, order) \
>> -	(!!thp_vma_allowable_orders(vma, vm_flags, smaps, in_pf, enforce_sysfs, BIT(order)))
>> +#define thp_vma_allowable_orders_insmaps(vma, vm_flags) \
>> +	(!!thp_vma_allowable_orders(vma, vm_flags, true, false, true, THP_ORDERS_ALL))
>> +
>> +#define thp_vma_allowable_orders_inpf(vma, vm_flags, orders) \
>> +	(!!thp_vma_allowable_orders(vma, vm_flags, false, true, true, orders))
>> +
>> +#define thp_vma_allowable_order_inpf(vma, vm_flags, order) \
>> +	(!!thp_vma_allowable_orders_inpf(vma, vm_flags, BIT(order)))
>> +
>> +#define thp_vma_allowable_pmd_order_inhuge(vma, vm_flags, enforce_sysfs) \
>> +	(!!thp_vma_allowable_orders(vma, vm_flags, false, false, enforce_sysfs, BIT(PMD_ORDER)))
> 
> nit: Personally I'd leave the order as an argument rather than encoding it in
> the name. It's likely that khugepaged will grow support for non-PMD-size
> collapse in future. The first part of the name "thp_vma_allowable_order" is then
> consistent and easy to search for all variants. And perhaps "inkhuge" is more
> precise?

Sure, thp_vma_allowable_order_inkhuge(vma, vm_flags, enforce_sysfs, order),
maybe add thp_vma_allowable_orders_inkhuge() like inpf in future.

Thanks.


> 
>> +
>>   
>>   #ifdef CONFIG_PGTABLE_HAS_HUGE_LEAVES
>>   #define HPAGE_PMD_SHIFT PMD_SHIFT
>> diff --git a/mm/khugepaged.c b/mm/khugepaged.c
>> index 2f73d2aa9ae8..5a27dccfda02 100644
>> --- a/mm/khugepaged.c
>> +++ b/mm/khugepaged.c
>> @@ -453,8 +453,7 @@ void khugepaged_enter_vma(struct vm_area_struct *vma,
>>   {
>>   	if (!test_bit(MMF_VM_HUGEPAGE, &vma->vm_mm->flags) &&
>>   	    hugepage_flags_enabled()) {
>> -		if (thp_vma_allowable_order(vma, vm_flags, false, false, true,
>> -					    PMD_ORDER))
>> +		if (thp_vma_allowable_pmd_order_inhuge(vma, vm_flags, true))
>>   			__khugepaged_enter(vma->vm_mm);
>>   	}
>>   }
>> @@ -909,15 +908,15 @@ static int hugepage_vma_revalidate(struct mm_struct *mm, unsigned long address,
>>   
>>   	if (!thp_vma_suitable_order(vma, address, PMD_ORDER))
>>   		return SCAN_ADDRESS_RANGE;
>> -	if (!thp_vma_allowable_order(vma, vma->vm_flags, false, false,
>> -				     cc->is_khugepaged, PMD_ORDER))
>> +	if (!thp_vma_allowable_pmd_order_inhuge(vma, vma->vm_flags,
>> +						cc->is_khugepaged))
>>   		return SCAN_VMA_CHECK;
>>   	/*
>>   	 * Anon VMA expected, the address may be unmapped then
>>   	 * remapped to file after khugepaged reaquired the mmap_lock.
>>   	 *
>> -	 * thp_vma_allowable_order may return true for qualified file
>> -	 * vmas.
>> +	 * thp_vma_allowable_pmd_order_inhuge may return true for
>> +	 * qualified file vmas.
>>   	 */
>>   	if (expect_anon && (!(*vmap)->anon_vma || !vma_is_anonymous(*vmap)))
>>   		return SCAN_PAGE_ANON;
>> @@ -1493,8 +1492,7 @@ int collapse_pte_mapped_thp(struct mm_struct *mm, unsigned long addr,
>>   	 * and map it by a PMD, regardless of sysfs THP settings. As such, let's
>>   	 * analogously elide sysfs THP settings here.
>>   	 */
>> -	if (!thp_vma_allowable_order(vma, vma->vm_flags, false, false, false,
>> -				     PMD_ORDER))
>> +	if (!thp_vma_allowable_pmd_order_inhuge(vma, vma->vm_flags, false))
>>   		return SCAN_VMA_CHECK;
>>   
>>   	/* Keep pmd pgtable for uffd-wp; see comment in retract_page_tables() */
>> @@ -2355,8 +2353,7 @@ static unsigned int khugepaged_scan_mm_slot(unsigned int pages, int *result,
>>   			progress++;
>>   			break;
>>   		}
>> -		if (!thp_vma_allowable_order(vma, vma->vm_flags, false, false,
>> -					     true, PMD_ORDER)) {
>> +		if (!thp_vma_allowable_pmd_order_inhuge(vma, vma->vm_flags, true)) {
>>   skip:
>>   			progress++;
>>   			continue;
>> @@ -2693,8 +2690,7 @@ int madvise_collapse(struct vm_area_struct *vma, struct vm_area_struct **prev,
>>   
>>   	*prev = vma;
>>   
>> -	if (!thp_vma_allowable_order(vma, vma->vm_flags, false, false, false,
>> -				     PMD_ORDER))
>> +	if (!thp_vma_allowable_pmd_order_inhuge(vma, vma->vm_flags, false))
>>   		return -EINVAL;
>>   
>>   	cc = kmalloc(sizeof(*cc), GFP_KERNEL);
>> diff --git a/mm/memory.c b/mm/memory.c
>> index 09ed76e5b8c0..8507bfda461a 100644
>> --- a/mm/memory.c
>> +++ b/mm/memory.c
>> @@ -4329,8 +4329,8 @@ static struct folio *alloc_anon_folio(struct vm_fault *vmf)
>>   	 * for this vma. Then filter out the orders that can't be allocated over
>>   	 * the faulting address and still be fully contained in the vma.
>>   	 */
>> -	orders = thp_vma_allowable_orders(vma, vma->vm_flags, false, true, true,
>> -					  BIT(PMD_ORDER) - 1);
>> +	orders = thp_vma_allowable_orders_inpf(vma, vma->vm_flags,
>> +					       BIT(PMD_ORDER) - 1);
>>   	orders = thp_vma_suitable_orders(vma, vmf->address, orders);
>>   
>>   	if (!orders)
>> @@ -5433,7 +5433,7 @@ static vm_fault_t __handle_mm_fault(struct vm_area_struct *vma,
>>   		return VM_FAULT_OOM;
>>   retry_pud:
>>   	if (pud_none(*vmf.pud) &&
>> -	    thp_vma_allowable_order(vma, vm_flags, false, true, true, PUD_ORDER)) {
>> +	    thp_vma_allowable_order_inpf(vma, vm_flags, PUD_ORDER)) {
>>   		ret = create_huge_pud(&vmf);
>>   		if (!(ret & VM_FAULT_FALLBACK))
>>   			return ret;
>> @@ -5467,7 +5467,7 @@ static vm_fault_t __handle_mm_fault(struct vm_area_struct *vma,
>>   		goto retry_pud;
>>   
>>   	if (pmd_none(*vmf.pmd) &&
>> -	    thp_vma_allowable_order(vma, vm_flags, false, true, true, PMD_ORDER)) {
>> +	    thp_vma_allowable_order_inpf(vma, vm_flags, PMD_ORDER)) {
>>   		ret = create_huge_pmd(&vmf);
>>   		if (!(ret & VM_FAULT_FALLBACK))
>>   			return ret;
>