[PATCH v2 06/11] hugetlb: make hugetlb_fault_mutex_hash() to take PAGE_SIZE index
From: Jane Chu
Date: Wed Jun 17 2026 - 13:29:18 EST
Make hugetlb_fault_mutex_hash() to take a PAGE_SIZE-based index.
This makes the helper interface consistent with filemap_get_folio(),
and linear_page_index(), while preserving the same lock selection for
a given hugetlb file offset.
Signed-off-by: Jane Chu <jane.chu@xxxxxxxxxx>
---
fs/hugetlbfs/inode.c | 9 ++++-----
include/linux/hugetlb.h | 2 +-
mm/hugetlb.c | 23 ++++++++++++-----------
mm/memfd.c | 9 +++++----
mm/userfaultfd.c | 6 +++---
5 files changed, 25 insertions(+), 24 deletions(-)
diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
index 1c25485c91b9..02cb265a580e 100644
--- a/fs/hugetlbfs/inode.c
+++ b/fs/hugetlbfs/inode.c
@@ -448,7 +448,7 @@ static void remove_inode_hugepages(struct inode *inode, loff_t lstart,
struct address_space *mapping = &inode->i_data;
const pgoff_t end = lend >> PAGE_SHIFT;
struct folio_batch fbatch;
- pgoff_t next, index;
+ pgoff_t next;
int i, freed = 0;
bool truncate_op = (lend == LLONG_MAX);
@@ -459,15 +459,14 @@ static void remove_inode_hugepages(struct inode *inode, loff_t lstart,
struct folio *folio = fbatch.folios[i];
u32 hash = 0;
- index = folio->index >> huge_page_order(h);
- hash = hugetlb_fault_mutex_hash(mapping, index);
+ hash = hugetlb_fault_mutex_hash(mapping, folio->index);
mutex_lock(&hugetlb_fault_mutex_table[hash]);
/*
* Remove folio that was part of folio_batch.
*/
remove_inode_single_folio(h, inode, mapping, folio,
- index, truncate_op);
+ folio->index, truncate_op);
freed++;
mutex_unlock(&hugetlb_fault_mutex_table[hash]);
@@ -664,7 +663,7 @@ static long hugetlbfs_fallocate(struct file *file, int mode, loff_t offset,
addr = index * hpage_size;
/* mutex taken here, fault path and hole punch */
- hash = hugetlb_fault_mutex_hash(mapping, index);
+ hash = hugetlb_fault_mutex_hash(mapping, index << huge_page_order(h));
mutex_lock(&hugetlb_fault_mutex_table[hash]);
/* See if already present in mapping to avoid alloc/free */
diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index 218284e80451..cae5cdd3ea00 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -159,7 +159,7 @@ void folio_putback_hugetlb(struct folio *folio);
void move_hugetlb_state(struct folio *old_folio, struct folio *new_folio, int reason);
void hugetlb_fix_reserve_counts(struct inode *inode);
extern struct mutex *hugetlb_fault_mutex_table;
-u32 hugetlb_fault_mutex_hash(struct address_space *mapping, pgoff_t idx);
+u32 hugetlb_fault_mutex_hash(struct address_space *mapping, pgoff_t index);
pte_t *huge_pmd_share(struct mm_struct *mm, struct vm_area_struct *vma,
unsigned long addr, pud_t *pud);
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 3255f6b762c9..ecd1d1322fda 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -5505,7 +5505,7 @@ static vm_fault_t hugetlb_wp(struct vm_fault *vmf)
*/
if (cow_from_owner) {
struct address_space *mapping = vma->vm_file->f_mapping;
- pgoff_t idx;
+ pgoff_t index;
u32 hash;
folio_put(old_folio);
@@ -5518,8 +5518,8 @@ static vm_fault_t hugetlb_wp(struct vm_fault *vmf)
*
* Reacquire both after unmap operation.
*/
- idx = vma_hugecache_offset(h, vma, vmf->address);
- hash = hugetlb_fault_mutex_hash(mapping, idx);
+ index = linear_page_index(vma, vmf->address);
+ hash = hugetlb_fault_mutex_hash(mapping, index);
hugetlb_vma_unlock_read(vma);
mutex_unlock(&hugetlb_fault_mutex_table[hash]);
@@ -5654,8 +5654,6 @@ static inline vm_fault_t hugetlb_handle_userfault(struct vm_fault *vmf,
unsigned long reason)
{
u32 hash;
- struct hstate *h = hstate_vma(vmf->vma);
- pgoff_t idx = vmf->pgoff >> huge_page_order(h);
/*
* vma_lock and hugetlb_fault_mutex must be dropped before handling
@@ -5663,7 +5661,7 @@ static inline vm_fault_t hugetlb_handle_userfault(struct vm_fault *vmf,
* userfault, any vma operation should be careful from here.
*/
hugetlb_vma_unlock_read(vmf->vma);
- hash = hugetlb_fault_mutex_hash(mapping, idx);
+ hash = hugetlb_fault_mutex_hash(mapping, vmf->pgoff);
mutex_unlock(&hugetlb_fault_mutex_table[hash]);
return handle_userfault(vmf, reason);
}
@@ -5896,7 +5894,7 @@ static vm_fault_t hugetlb_no_page(struct address_space *mapping,
if (unlikely(ret & VM_FAULT_RETRY))
vma_end_read(vma);
- hash = hugetlb_fault_mutex_hash(mapping, idx);
+ hash = hugetlb_fault_mutex_hash(mapping, vmf->pgoff);
mutex_unlock(&hugetlb_fault_mutex_table[hash]);
return ret;
@@ -5913,13 +5911,16 @@ static vm_fault_t hugetlb_no_page(struct address_space *mapping,
}
#ifdef CONFIG_SMP
-u32 hugetlb_fault_mutex_hash(struct address_space *mapping, pgoff_t idx)
+u32 hugetlb_fault_mutex_hash(struct address_space *mapping, pgoff_t index)
{
unsigned long key[2];
+ struct hstate *h;
u32 hash;
key[0] = (unsigned long) mapping;
- key[1] = idx;
+
+ h = hstate_inode(mapping->host);
+ key[1] = index >> huge_page_order(h);
hash = jhash2((u32 *)&key, sizeof(key)/(sizeof(u32)), 0);
@@ -5930,7 +5931,7 @@ u32 hugetlb_fault_mutex_hash(struct address_space *mapping, pgoff_t idx)
* For uniprocessor systems we always use a single mutex, so just
* return 0 and avoid the hashing overhead.
*/
-u32 hugetlb_fault_mutex_hash(struct address_space *mapping, pgoff_t idx)
+u32 hugetlb_fault_mutex_hash(struct address_space *mapping, pgoff_t index)
{
return 0;
}
@@ -5965,7 +5966,7 @@ vm_fault_t hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
* the same page in the page cache.
*/
mapping = vma->vm_file->f_mapping;
- hash = hugetlb_fault_mutex_hash(mapping, vmf.pgoff >> huge_page_order(h));
+ hash = hugetlb_fault_mutex_hash(mapping, vmf.pgoff);
mutex_lock(&hugetlb_fault_mutex_table[hash]);
/*
diff --git a/mm/memfd.c b/mm/memfd.c
index abe13b291ddc..b0ec0b12b98d 100644
--- a/mm/memfd.c
+++ b/mm/memfd.c
@@ -64,7 +64,7 @@ static void memfd_tag_pins(struct xa_state *xas)
* (memfd_pin_folios()) cannot find a folio in the page cache at a given
* index in the mapping.
*/
-struct folio *memfd_alloc_folio(struct file *memfd, pgoff_t idx)
+struct folio *memfd_alloc_folio(struct file *memfd, pgoff_t index)
{
#ifdef CONFIG_HUGETLB_PAGE
struct folio *folio;
@@ -79,12 +79,13 @@ struct folio *memfd_alloc_folio(struct file *memfd, pgoff_t idx)
*/
struct inode *inode = file_inode(memfd);
struct hstate *h = hstate_file(memfd);
+ pgoff_t idx;
int err = -ENOMEM;
long nr_resv;
gfp_mask = htlb_alloc_mask(h);
gfp_mask &= ~(__GFP_HIGHMEM | __GFP_MOVABLE);
- idx >>= huge_page_order(h);
+ idx = index >> huge_page_order(h);
nr_resv = hugetlb_reserve_pages(inode, idx, idx + 1, NULL, EMPTY_VMA_FLAGS);
if (nr_resv < 0)
@@ -116,7 +117,7 @@ struct folio *memfd_alloc_folio(struct file *memfd, pgoff_t idx)
* races with concurrent allocations, as required by all other
* callers of hugetlb_add_to_page_cache().
*/
- hash = hugetlb_fault_mutex_hash(memfd->f_mapping, idx);
+ hash = hugetlb_fault_mutex_hash(memfd->f_mapping, index);
mutex_lock(&hugetlb_fault_mutex_table[hash]);
err = hugetlb_add_to_page_cache(folio,
@@ -140,7 +141,7 @@ struct folio *memfd_alloc_folio(struct file *memfd, pgoff_t idx)
return ERR_PTR(err);
}
#endif
- return shmem_read_folio(memfd->f_mapping, idx);
+ return shmem_read_folio(memfd->f_mapping, index);
}
/*
diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c
index 180bad42fc79..95fb94b697a4 100644
--- a/mm/userfaultfd.c
+++ b/mm/userfaultfd.c
@@ -707,7 +707,7 @@ static __always_inline ssize_t mfill_atomic_hugetlb(
long copied;
struct folio *folio;
unsigned long vma_hpagesize;
- pgoff_t idx;
+ pgoff_t index;
u32 hash;
struct address_space *mapping;
@@ -776,9 +776,9 @@ static __always_inline ssize_t mfill_atomic_hugetlb(
* in the case of shared pmds. fault mutex prevents
* races with other faulting threads.
*/
- idx = hugetlb_linear_page_index(dst_vma, dst_addr);
+ index = linear_page_index(dst_vma, dst_addr);
mapping = dst_vma->vm_file->f_mapping;
- hash = hugetlb_fault_mutex_hash(mapping, idx);
+ hash = hugetlb_fault_mutex_hash(mapping, index);
mutex_lock(&hugetlb_fault_mutex_table[hash]);
hugetlb_vma_lock_read(dst_vma);
--
2.43.5