Re: [PATCH v13 mm-new 01/16] khugepaged: rename hpage_collapse_* to collapse_*

[Lorenzo Stoakes <lorenzo.stoakes@oracle.com>]

FYI there's a merge conflict vs. mm-unstable atm (mm-new is unworkably broken,
so prefer to base on mm-unstable if possible thanks).

In mm/khugepaged.c:

<<<<<<< HEAD
static enum scan_result hpage_collapse_scan_pmd(struct mm_struct *mm,
						struct vm_area_struct *vma,
						unsigned long start_addr, bool *mmap_locked,
						struct collapse_control *cc)
=======
static int collapse_scan_pmd(struct mm_struct *mm,
			     struct vm_area_struct *vma,
			     unsigned long start_addr, bool *mmap_locked,
			     struct collapse_control *cc)
>>>>>>> khugepaged: rename hpage_collapse_* to collapse_*

<<<<<<< HEAD
static enum scan_result hpage_collapse_scan_file(struct mm_struct *mm, unsigned long addr,
						 struct file *file, pgoff_t start,
						 struct collapse_control *cc)
=======
static int collapse_scan_file(struct mm_struct *mm, unsigned long addr,
			      struct file *file, pgoff_t start,
			      struct collapse_control *cc)
>>>>>>> khugepaged: rename hpage_collapse_* to collapse_*

<<<<<<< HEAD
static unsigned int khugepaged_scan_mm_slot(unsigned int pages, enum scan_result *result,
=======
static unsigned int collapse_scan_mm_slot(unsigned int pages, int *result,
>>>>>>> khugepaged: rename hpage_collapse_* to collapse_*

<<<<<<< HEAD
static enum scan_result hpage_collapse_scan_file(struct mm_struct *mm, unsigned long addr,
						 struct file *file, pgoff_t start,
						 struct collapse_control *cc)
=======
static int collapse_scan_file(struct mm_struct *mm, unsigned long addr,
			      struct file *file, pgoff_t start,
			      struct collapse_control *cc)
>>>>>>> khugepaged: rename hpage_collapse_* to collapse_*

Maybe worth just double-tab indenting the args on subsequent lines to make
dealing with this kind of thing a bit easier in general? Tab/space alignment to
function name, while neat, can be a pain when return type changes.

On Mon, Dec 01, 2025 at 10:46:12AM -0700, Nico Pache wrote:
> The hpage_collapse functions describe functions used by madvise_collapse
> and khugepaged. remove the unnecessary hpage prefix to shorten the
> function name.
>
> Reviewed-by: Wei Yang <richard.weiyang@gmail.com>
> Reviewed-by: Lance Yang <lance.yang@linux.dev>
> Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
> Reviewed-by: Zi Yan <ziy@nvidia.com>
> Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
> Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
> Acked-by: David Hildenbrand <david@redhat.com>
> Signed-off-by: Nico Pache <npache@redhat.com>
> ---
>  mm/khugepaged.c | 73 ++++++++++++++++++++++++-------------------------
>  mm/mremap.c     |  2 +-
>  2 files changed, 37 insertions(+), 38 deletions(-)
>
> diff --git a/mm/khugepaged.c b/mm/khugepaged.c
> index 97d1b2824386..959be77f2e65 100644
> --- a/mm/khugepaged.c
> +++ b/mm/khugepaged.c
> @@ -394,14 +394,14 @@ void __init khugepaged_destroy(void)
>  	kmem_cache_destroy(mm_slot_cache);
>  }
>
> -static inline int hpage_collapse_test_exit(struct mm_struct *mm)
> +static inline int collapse_test_exit(struct mm_struct *mm)
>  {
>  	return atomic_read(&mm->mm_users) == 0;
>  }
>
> -static inline int hpage_collapse_test_exit_or_disable(struct mm_struct *mm)
> +static inline int collapse_test_exit_or_disable(struct mm_struct *mm)
>  {
> -	return hpage_collapse_test_exit(mm) ||
> +	return collapse_test_exit(mm) ||
>  		mm_flags_test(MMF_DISABLE_THP_COMPLETELY, mm);
>  }
>
> @@ -435,7 +435,7 @@ void __khugepaged_enter(struct mm_struct *mm)
>  	int wakeup;
>
>  	/* __khugepaged_exit() must not run from under us */
> -	VM_BUG_ON_MM(hpage_collapse_test_exit(mm), mm);
> +	VM_BUG_ON_MM(collapse_test_exit(mm), mm);
>  	if (unlikely(mm_flags_test_and_set(MMF_VM_HUGEPAGE, mm)))
>  		return;
>
> @@ -489,7 +489,7 @@ void __khugepaged_exit(struct mm_struct *mm)
>  	} else if (slot) {
>  		/*
>  		 * This is required to serialize against
> -		 * hpage_collapse_test_exit() (which is guaranteed to run
> +		 * collapse_test_exit() (which is guaranteed to run
>  		 * under mmap sem read mode). Stop here (after we return all
>  		 * pagetables will be destroyed) until khugepaged has finished
>  		 * working on the pagetables under the mmap_lock.
> @@ -579,7 +579,7 @@ static int __collapse_huge_page_isolate(struct vm_area_struct *vma,
>  		folio = page_folio(page);
>  		VM_BUG_ON_FOLIO(!folio_test_anon(folio), folio);
>
> -		/* See hpage_collapse_scan_pmd(). */
> +		/* See collapse_scan_pmd(). */
>  		if (folio_maybe_mapped_shared(folio)) {
>  			++shared;
>  			if (cc->is_khugepaged &&
> @@ -830,7 +830,7 @@ struct collapse_control khugepaged_collapse_control = {
>  	.is_khugepaged = true,
>  };
>
> -static bool hpage_collapse_scan_abort(int nid, struct collapse_control *cc)
> +static bool collapse_scan_abort(int nid, struct collapse_control *cc)
>  {
>  	int i;
>
> @@ -865,7 +865,7 @@ static inline gfp_t alloc_hugepage_khugepaged_gfpmask(void)
>  }
>
>  #ifdef CONFIG_NUMA
> -static int hpage_collapse_find_target_node(struct collapse_control *cc)
> +static int collapse_find_target_node(struct collapse_control *cc)
>  {
>  	int nid, target_node = 0, max_value = 0;
>
> @@ -884,7 +884,7 @@ static int hpage_collapse_find_target_node(struct collapse_control *cc)
>  	return target_node;
>  }
>  #else
> -static int hpage_collapse_find_target_node(struct collapse_control *cc)
> +static int collapse_find_target_node(struct collapse_control *cc)
>  {
>  	return 0;
>  }
> @@ -905,7 +905,7 @@ static int hugepage_vma_revalidate(struct mm_struct *mm, unsigned long address,
>  	enum tva_type type = cc->is_khugepaged ? TVA_KHUGEPAGED :
>  				 TVA_FORCED_COLLAPSE;
>
> -	if (unlikely(hpage_collapse_test_exit_or_disable(mm)))
> +	if (unlikely(collapse_test_exit_or_disable(mm)))
>  		return SCAN_ANY_PROCESS;
>
>  	*vmap = vma = find_vma(mm, address);
> @@ -978,7 +978,7 @@ static int check_pmd_still_valid(struct mm_struct *mm,
>
>  /*
>   * Bring missing pages in from swap, to complete THP collapse.
> - * Only done if hpage_collapse_scan_pmd believes it is worthwhile.
> + * Only done if khugepaged_scan_pmd believes it is worthwhile.
>   *
>   * Called and returns without pte mapped or spinlocks held.
>   * Returns result: if not SCAN_SUCCEED, mmap_lock has been released.
> @@ -1065,7 +1065,7 @@ static int alloc_charge_folio(struct folio **foliop, struct mm_struct *mm,
>  {
>  	gfp_t gfp = (cc->is_khugepaged ? alloc_hugepage_khugepaged_gfpmask() :
>  		     GFP_TRANSHUGE);
> -	int node = hpage_collapse_find_target_node(cc);
> +	int node = collapse_find_target_node(cc);
>  	struct folio *folio;
>
>  	folio = __folio_alloc(gfp, HPAGE_PMD_ORDER, node, &cc->alloc_nmask);
> @@ -1244,10 +1244,10 @@ static int collapse_huge_page(struct mm_struct *mm, unsigned long address,
>  	return result;
>  }
>
> -static int hpage_collapse_scan_pmd(struct mm_struct *mm,
> -				   struct vm_area_struct *vma,
> -				   unsigned long start_addr, bool *mmap_locked,
> -				   struct collapse_control *cc)
> +static int collapse_scan_pmd(struct mm_struct *mm,
> +			     struct vm_area_struct *vma,
> +			     unsigned long start_addr, bool *mmap_locked,
> +			     struct collapse_control *cc)
>  {
>  	pmd_t *pmd;
>  	pte_t *pte, *_pte;
> @@ -1355,7 +1355,7 @@ static int hpage_collapse_scan_pmd(struct mm_struct *mm,
>  		 * hit record.
>  		 */
>  		node = folio_nid(folio);
> -		if (hpage_collapse_scan_abort(node, cc)) {
> +		if (collapse_scan_abort(node, cc)) {
>  			result = SCAN_SCAN_ABORT;
>  			goto out_unmap;
>  		}
> @@ -1421,7 +1421,7 @@ static void collect_mm_slot(struct mm_slot *slot)
>
>  	lockdep_assert_held(&khugepaged_mm_lock);
>
> -	if (hpage_collapse_test_exit(mm)) {
> +	if (collapse_test_exit(mm)) {
>  		/* free mm_slot */
>  		hash_del(&slot->hash);
>  		list_del(&slot->mm_node);
> @@ -1769,7 +1769,7 @@ static void retract_page_tables(struct address_space *mapping, pgoff_t pgoff)
>  		if (find_pmd_or_thp_or_none(mm, addr, &pmd) != SCAN_SUCCEED)
>  			continue;
>
> -		if (hpage_collapse_test_exit(mm))
> +		if (collapse_test_exit(mm))
>  			continue;
>
>  		if (!file_backed_vma_is_retractable(vma))
> @@ -2285,9 +2285,9 @@ static int collapse_file(struct mm_struct *mm, unsigned long addr,
>  	return result;
>  }
>
> -static int hpage_collapse_scan_file(struct mm_struct *mm, unsigned long addr,
> -				    struct file *file, pgoff_t start,
> -				    struct collapse_control *cc)
> +static int collapse_scan_file(struct mm_struct *mm, unsigned long addr,
> +			      struct file *file, pgoff_t start,
> +			      struct collapse_control *cc)
>  {
>  	struct folio *folio = NULL;
>  	struct address_space *mapping = file->f_mapping;
> @@ -2342,7 +2342,7 @@ static int hpage_collapse_scan_file(struct mm_struct *mm, unsigned long addr,
>  		}
>
>  		node = folio_nid(folio);
> -		if (hpage_collapse_scan_abort(node, cc)) {
> +		if (collapse_scan_abort(node, cc)) {
>  			result = SCAN_SCAN_ABORT;
>  			folio_put(folio);
>  			break;
> @@ -2392,7 +2392,7 @@ static int hpage_collapse_scan_file(struct mm_struct *mm, unsigned long addr,
>  	return result;
>  }
>
> -static unsigned int khugepaged_scan_mm_slot(unsigned int pages, int *result,
> +static unsigned int collapse_scan_mm_slot(unsigned int pages, int *result,
>  					    struct collapse_control *cc)
>  	__releases(&khugepaged_mm_lock)
>  	__acquires(&khugepaged_mm_lock)
> @@ -2427,7 +2427,7 @@ static unsigned int khugepaged_scan_mm_slot(unsigned int pages, int *result,
>  		goto breakouterloop_mmap_lock;
>
>  	progress++;
> -	if (unlikely(hpage_collapse_test_exit_or_disable(mm)))
> +	if (unlikely(collapse_test_exit_or_disable(mm)))
>  		goto breakouterloop;
>
>  	vma_iter_init(&vmi, mm, khugepaged_scan.address);
> @@ -2435,7 +2435,7 @@ static unsigned int khugepaged_scan_mm_slot(unsigned int pages, int *result,
>  		unsigned long hstart, hend;
>
>  		cond_resched();
> -		if (unlikely(hpage_collapse_test_exit_or_disable(mm))) {
> +		if (unlikely(collapse_test_exit_or_disable(mm))) {
>  			progress++;
>  			break;
>  		}
> @@ -2456,7 +2456,7 @@ static unsigned int khugepaged_scan_mm_slot(unsigned int pages, int *result,
>  			bool mmap_locked = true;
>
>  			cond_resched();
> -			if (unlikely(hpage_collapse_test_exit_or_disable(mm)))
> +			if (unlikely(collapse_test_exit_or_disable(mm)))
>  				goto breakouterloop;
>
>  			VM_BUG_ON(khugepaged_scan.address < hstart ||
> @@ -2469,12 +2469,12 @@ static unsigned int khugepaged_scan_mm_slot(unsigned int pages, int *result,
>
>  				mmap_read_unlock(mm);
>  				mmap_locked = false;
> -				*result = hpage_collapse_scan_file(mm,
> +				*result = collapse_scan_file(mm,
>  					khugepaged_scan.address, file, pgoff, cc);
>  				fput(file);
>  				if (*result == SCAN_PTE_MAPPED_HUGEPAGE) {
>  					mmap_read_lock(mm);
> -					if (hpage_collapse_test_exit_or_disable(mm))
> +					if (collapse_test_exit_or_disable(mm))
>  						goto breakouterloop;
>  					*result = collapse_pte_mapped_thp(mm,
>  						khugepaged_scan.address, false);
> @@ -2483,7 +2483,7 @@ static unsigned int khugepaged_scan_mm_slot(unsigned int pages, int *result,
>  					mmap_read_unlock(mm);
>  				}
>  			} else {
> -				*result = hpage_collapse_scan_pmd(mm, vma,
> +				*result = collapse_scan_pmd(mm, vma,
>  					khugepaged_scan.address, &mmap_locked, cc);
>  			}
>
> @@ -2516,7 +2516,7 @@ static unsigned int khugepaged_scan_mm_slot(unsigned int pages, int *result,
>  	 * Release the current mm_slot if this mm is about to die, or
>  	 * if we scanned all vmas of this mm.
>  	 */
> -	if (hpage_collapse_test_exit(mm) || !vma) {
> +	if (collapse_test_exit(mm) || !vma) {
>  		/*
>  		 * Make sure that if mm_users is reaching zero while
>  		 * khugepaged runs here, khugepaged_exit will find
> @@ -2567,8 +2567,8 @@ static void khugepaged_do_scan(struct collapse_control *cc)
>  			pass_through_head++;
>  		if (khugepaged_has_work() &&
>  		    pass_through_head < 2)
> -			progress += khugepaged_scan_mm_slot(pages - progress,
> -							    &result, cc);
> +			progress += collapse_scan_mm_slot(pages - progress,
> +							  &result, cc);
>  		else
>  			progress = pages;
>  		spin_unlock(&khugepaged_mm_lock);
> @@ -2807,12 +2807,11 @@ int madvise_collapse(struct vm_area_struct *vma, unsigned long start,
>
>  			mmap_read_unlock(mm);
>  			mmap_locked = false;
> -			result = hpage_collapse_scan_file(mm, addr, file, pgoff,
> -							  cc);
> +			result = collapse_scan_file(mm, addr, file, pgoff, cc);
>  			fput(file);
>  		} else {
> -			result = hpage_collapse_scan_pmd(mm, vma, addr,
> -							 &mmap_locked, cc);
> +			result = collapse_scan_pmd(mm, vma, addr,
> +						   &mmap_locked, cc);
>  		}
>  		if (!mmap_locked)
>  			*lock_dropped = true;
> diff --git a/mm/mremap.c b/mm/mremap.c
> index 672264807db6..db31d0231e05 100644
> --- a/mm/mremap.c
> +++ b/mm/mremap.c
> @@ -244,7 +244,7 @@ static int move_ptes(struct pagetable_move_control *pmc,
>  		goto out;
>  	}
>  	/*
> -	 * Now new_pte is none, so hpage_collapse_scan_file() path can not find
> +	 * Now new_pte is none, so collapse_scan_file() path can not find
>  	 * this by traversing file->f_mapping, so there is no concurrency with
>  	 * retract_page_tables(). In addition, we already hold the exclusive
>  	 * mmap_lock, so this new_pte page is stable, so there is no need to get
> --
> 2.51.1
>