[PATCH] support tmpfs hugepage PMD is not split when COW

[PATCH] support tmpfs hugepage PMD is not split when COW

[Chen Haixiang]

Transparent hugepages in tmpfs can enhance TLB efficiency by reducing
TLB misses. However, during Copy-On-Write (COW) memory faults, these
hugepages may be split. In some scenarios, preventing this splitting
is desirable. We might introduce a shmem_huge_fault to inhibit this
behavior, along with a mount parameter to enable or disable this function.

Signed-off-by: Chen Haixiang <chenhaixiang3@huawei.com>
---
 include/linux/mm.h       |  1 +
 include/linux/shmem_fs.h |  1 +
 mm/memory.c              |  7 ++++
 mm/shmem.c               | 85 ++++++++++++++++++++++++++++++++++++++++
 4 files changed, 94 insertions(+)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index da5219b48d52..eb44574965d6 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -573,6 +573,7 @@ struct vm_operations_struct {
 			unsigned long end, unsigned long newflags);
 	vm_fault_t (*fault)(struct vm_fault *vmf);
 	vm_fault_t (*huge_fault)(struct vm_fault *vmf, unsigned int order);
+	vm_fault_t (*shmem_huge_fault)(struct vm_fault *vmf, pmd_t orig_pmd);
 	vm_fault_t (*map_pages)(struct vm_fault *vmf,
 			pgoff_t start_pgoff, pgoff_t end_pgoff);
 	unsigned long (*pagesize)(struct vm_area_struct * area);
diff --git a/include/linux/shmem_fs.h b/include/linux/shmem_fs.h
index 2caa6b86106a..4484f2f33afe 100644
--- a/include/linux/shmem_fs.h
+++ b/include/linux/shmem_fs.h
@@ -73,6 +73,7 @@ struct shmem_sb_info {
 	struct list_head shrinklist;  /* List of shinkable inodes */
 	unsigned long shrinklist_len; /* Length of shrinklist */
 	struct shmem_quota_limits qlimits; /* Default quota limits */
+	unsigned int no_split;  /* Do not split shmempmdmaped in tmpfs */
 };
 
 static inline struct shmem_inode_info *SHMEM_I(struct inode *inode)
diff --git a/mm/memory.c b/mm/memory.c
index 5c757fba8858..7d27a6b5e69f 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -4942,6 +4942,13 @@ static inline vm_fault_t wp_huge_pmd(struct vm_fault *vmf)
 		}
 	}
 
+	if (vmf->vma->vm_ops->shmem_huge_fault) {
+		vm_fault_t ret = vmf->vma->vm_ops->shmem_huge_fault(vmf, vmf->orig_pmd);
+
+		if (!(ret & VM_FAULT_FALLBACK))
+			return ret;
+	}
+
 split:
 	/* COW or write-notify handled on pte level: split pmd. */
 	__split_huge_pmd(vma, vmf->pmd, vmf->address, false, NULL);
diff --git a/mm/shmem.c b/mm/shmem.c
index 0d1ce70bce38..8211211f7405 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -118,6 +118,7 @@ struct shmem_options {
 	umode_t mode;
 	bool full_inums;
 	int huge;
+	unsigned int no_split;
 	int seen;
 	bool noswap;
 	unsigned short quota_types;
@@ -128,6 +129,7 @@ struct shmem_options {
 #define SHMEM_SEEN_INUMS 8
 #define SHMEM_SEEN_NOSWAP 16
 #define SHMEM_SEEN_QUOTA 32
+#define SHMEM_SEEN_NO_SPLIT 64
 };
 
 #ifdef CONFIG_TMPFS
@@ -2238,6 +2240,79 @@ static vm_fault_t shmem_fault(struct vm_fault *vmf)
 	return ret;
 }
 
+static vm_fault_t shmem_huge_fault(struct vm_fault *vmf, pmd_t orig_pmd)
+{
+	vm_fault_t ret = VM_FAULT_FALLBACK;
+	unsigned long haddr = vmf->address & HPAGE_PMD_MASK;
+	struct folio *old_folio, *new_folio;
+	pmd_t entry;
+	int gfp_flags = GFP_HIGHUSER_MOVABLE | __GFP_COMP;
+	struct vm_area_struct *vma = vmf->vma;
+	struct shmem_sb_info *sbinfo = NULL;
+	struct inode *inode = file_inode(vma->vm_file);
+	struct shmem_inode_info *info = SHMEM_I(inode);
+
+	sbinfo = SHMEM_SB(info->vfs_inode.i_sb);
+
+	if (sbinfo->no_split == 0)
+		return VM_FAULT_FALLBACK;
+
+	/* ShmemPmdMapped in tmpfs will not split huge pmd */
+	if (!(vmf->flags & FAULT_FLAG_WRITE)
+			|| (vma->vm_flags & VM_SHARED))
+		return VM_FAULT_FALLBACK;
+
+	new_folio = vma_alloc_folio(gfp_flags, HPAGE_PMD_ORDER,
+			vmf->vma, haddr, true);
+	if (!new_folio)
+		ret = VM_FAULT_FALLBACK;
+
+	vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd);
+	if (pmd_none(*vmf->pmd)) {
+		ret = VM_FAULT_FALLBACK;
+		goto out;
+	}
+	if (!pmd_same(*vmf->pmd, orig_pmd)) {
+		ret = 0;
+		goto out;
+	}
+
+	if (!new_folio) {
+		count_vm_event(THP_FAULT_FALLBACK);
+		ret = VM_FAULT_FALLBACK;
+		goto out;
+	}
+	old_folio = page_folio(pmd_page(*vmf->pmd));
+	page_remove_rmap(&old_folio->page, vma, true);
+	pmdp_huge_clear_flush(vma, haddr, vmf->pmd);
+
+	__folio_set_locked(new_folio);
+	__folio_set_swapbacked(new_folio);
+	__folio_mark_uptodate(new_folio);
+
+	flush_icache_pages(vma, &new_folio->page, HPAGE_PMD_NR);
+	entry = mk_huge_pmd(&new_folio->page, vma->vm_page_prot);
+	entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma);
+
+	page_add_file_rmap(&new_folio->page, vma, true);
+	set_pmd_at(vma->vm_mm, haddr, vmf->pmd, entry);
+	update_mmu_cache_pmd(vma, haddr, vmf->pmd);
+	count_vm_event(THP_FILE_MAPPED);
+
+	folio_unlock(new_folio);
+	spin_unlock(vmf->ptl);
+	copy_user_large_folio(new_folio, old_folio, haddr, vma);
+	folio_put(old_folio);
+	ret = 0;
+	return ret;
+
+out:
+	if (new_folio)
+		folio_put(new_folio);
+	spin_unlock(vmf->ptl);
+	return ret;
+}
+
 unsigned long shmem_get_unmapped_area(struct file *file,
 				      unsigned long uaddr, unsigned long len,
 				      unsigned long pgoff, unsigned long flags)
@@ -3869,6 +3944,7 @@ enum shmem_param {
 	Opt_usrquota_inode_hardlimit,
 	Opt_grpquota_block_hardlimit,
 	Opt_grpquota_inode_hardlimit,
+	Opt_no_split,
 };
 
 static const struct constant_table shmem_param_enums_huge[] = {
@@ -3900,6 +3976,7 @@ const struct fs_parameter_spec shmem_fs_parameters[] = {
 	fsparam_string("grpquota_block_hardlimit", Opt_grpquota_block_hardlimit),
 	fsparam_string("grpquota_inode_hardlimit", Opt_grpquota_inode_hardlimit),
 #endif
+	fsparam_u32   ("no_split",	Opt_no_split),
 	{}
 };
 
@@ -4065,6 +4142,10 @@ static int shmem_parse_one(struct fs_context *fc, struct fs_parameter *param)
 				       "Group quota inode hardlimit too large.");
 		ctx->qlimits.grpquota_ihardlimit = size;
 		break;
+	case Opt_no_split:
+		ctx->no_split = result.uint_32;
+		ctx->seen |= SHMEM_SEEN_NO_SPLIT;
+		break;
 	}
 	return 0;
 
@@ -4261,6 +4342,8 @@ static int shmem_show_options(struct seq_file *seq, struct dentry *root)
 	/* Rightly or wrongly, show huge mount option unmasked by shmem_huge */
 	if (sbinfo->huge)
 		seq_printf(seq, ",huge=%s", shmem_format_huge(sbinfo->huge));
+	if (sbinfo->huge && sbinfo->no_split)
+		seq_puts(seq, ",no_split");
 #endif
 	mpol = shmem_get_sbmpol(sbinfo);
 	shmem_show_mpol(seq, mpol);
@@ -4315,6 +4398,7 @@ static int shmem_fill_super(struct super_block *sb, struct fs_context *fc)
 		if (!(ctx->seen & SHMEM_SEEN_INUMS))
 			ctx->full_inums = IS_ENABLED(CONFIG_TMPFS_INODE64);
 		sbinfo->noswap = ctx->noswap;
+		sbinfo->no_split = ctx->no_split;
 	} else {
 		sb->s_flags |= SB_NOUSER;
 	}
@@ -4568,6 +4652,7 @@ static const struct super_operations shmem_ops = {
 static const struct vm_operations_struct shmem_vm_ops = {
 	.fault		= shmem_fault,
 	.map_pages	= filemap_map_pages,
+	.shmem_huge_fault	= shmem_huge_fault,
 #ifdef CONFIG_NUMA
 	.set_policy     = shmem_set_policy,
 	.get_policy     = shmem_get_policy,
-- 
2.33.0

Re: [PATCH] support tmpfs hugepage PMD is not split when COW

[David Hildenbrand]

On 10.01.24 10:20, Chen Haixiang wrote:
> Transparent hugepages in tmpfs can enhance TLB efficiency by reducing
> TLB misses. However, during Copy-On-Write (COW) memory faults, these
> hugepages may be split. In some scenarios, preventing this splitting
> is desirable. We might introduce a shmem_huge_fault to inhibit this
> behavior, along with a mount parameter to enable or disable this function.
> 

I'm confused, can you describe the problem a bit better, because ...

> Signed-off-by: Chen Haixiang <chenhaixiang3@huawei.com>
> ---


[...]

>   
> +static vm_fault_t shmem_huge_fault(struct vm_fault *vmf, pmd_t orig_pmd)
> +{
> +	vm_fault_t ret = VM_FAULT_FALLBACK;
> +	unsigned long haddr = vmf->address & HPAGE_PMD_MASK;
> +	struct folio *old_folio, *new_folio;
> +	pmd_t entry;
> +	int gfp_flags = GFP_HIGHUSER_MOVABLE | __GFP_COMP;
> +	struct vm_area_struct *vma = vmf->vma;
> +	struct shmem_sb_info *sbinfo = NULL;
> +	struct inode *inode = file_inode(vma->vm_file);
> +	struct shmem_inode_info *info = SHMEM_I(inode);
> +
> +	sbinfo = SHMEM_SB(info->vfs_inode.i_sb);
> +
> +	if (sbinfo->no_split == 0)
> +		return VM_FAULT_FALLBACK;
> +
> +	/* ShmemPmdMapped in tmpfs will not split huge pmd */
> +	if (!(vmf->flags & FAULT_FLAG_WRITE)
> +			|| (vma->vm_flags & VM_SHARED))
> +		return VM_FAULT_FALLBACK;

We do have a private (COW) mapping at this point, and

> +
> +	new_folio = vma_alloc_folio(gfp_flags, HPAGE_PMD_ORDER,
> +			vmf->vma, haddr, true);
> +	if (!new_folio)
> +		ret = VM_FAULT_FALLBACK;
> +
> +	vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd);
> +	if (pmd_none(*vmf->pmd)) {
> +		ret = VM_FAULT_FALLBACK;
> +		goto out;
> +	}
> +	if (!pmd_same(*vmf->pmd, orig_pmd)) {
> +		ret = 0;
> +		goto out;
> +	}
> +
> +	if (!new_folio) {
> +		count_vm_event(THP_FAULT_FALLBACK);
> +		ret = VM_FAULT_FALLBACK;
> +		goto out;
> +	}
> +	old_folio = page_folio(pmd_page(*vmf->pmd));
> +	page_remove_rmap(&old_folio->page, vma, true);
> +	pmdp_huge_clear_flush(vma, haddr, vmf->pmd);
> +
> +	__folio_set_locked(new_folio);
> +	__folio_set_swapbacked(new_folio);
> +	__folio_mark_uptodate(new_folio);

We allocate a fresh folio here and

> +
> +	flush_icache_pages(vma, &new_folio->page, HPAGE_PMD_NR);
> +	entry = mk_huge_pmd(&new_folio->page, vma->vm_page_prot);
> +	entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma);
> +
> +	page_add_file_rmap(&new_folio->page, vma, true);

it is not an anonymous one?

... but your are making it writable? In a private mapping?

> +	set_pmd_at(vma->vm_mm, haddr, vmf->pmd, entry);
> +	update_mmu_cache_pmd(vma, haddr, vmf->pmd);
> +	count_vm_event(THP_FILE_MAPPED);

And still acoount it as a file folio? But never add it so some pagecache 
structure?


I'm probably missing something, or something is completely wrong here.

-- 
Cheers,

David / dhildenb

Re: [PATCH] support tmpfs hugepage PMD is not split when COW

[Matthew Wilcox]

On Wed, Jan 10, 2024 at 05:20:28PM +0800, Chen Haixiang wrote:
> +++ b/include/linux/mm.h
> @@ -573,6 +573,7 @@ struct vm_operations_struct {
>  			unsigned long end, unsigned long newflags);
>  	vm_fault_t (*fault)(struct vm_fault *vmf);
>  	vm_fault_t (*huge_fault)(struct vm_fault *vmf, unsigned int order);
> +	vm_fault_t (*shmem_huge_fault)(struct vm_fault *vmf, pmd_t orig_pmd);

No new operation for this.

> +++ b/mm/memory.c
> @@ -4942,6 +4942,13 @@ static inline vm_fault_t wp_huge_pmd(struct vm_fault *vmf)
>  		}
>  	}
>  
> +	if (vmf->vma->vm_ops->shmem_huge_fault) {
> +		vm_fault_t ret = vmf->vma->vm_ops->shmem_huge_fault(vmf, vmf->orig_pmd);
> +
> +		if (!(ret & VM_FAULT_FALLBACK))
> +			return ret;
> +	}

Why would you do this when ->huge_fault is called in the stanza above?

Re: [PATCH] support tmpfs hugepage PMD is not split when COW

[kernel test robot]

Hi Chen,

kernel test robot noticed the following build errors:

[auto build test ERROR on akpm-mm/mm-everything]
[also build test ERROR on linus/master v6.7 next-20240110]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Chen-Haixiang/support-tmpfs-hugepage-PMD-is-not-split-when-COW/20240110-172314
base:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
patch link:    https://lore.kernel.org/r/20240110092028.1777-1-chenhaixiang3%40huawei.com
patch subject: [PATCH] support tmpfs hugepage PMD is not split when COW
config: arm-mmp2_defconfig (https://download.01.org/0day-ci/archive/20240111/202401110739.T5OMND7z-lkp@intel.com/config)
compiler: clang version 15.0.7 (https://github.com/llvm/llvm-project.git 8dfdcc7b7bf66834a761bd8de445840ef68e4d1a)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240111/202401110739.T5OMND7z-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202401110739.T5OMND7z-lkp@intel.com/

All errors (new ones prefixed by >>):

   mm/shmem.c:2278:18: error: use of undeclared identifier 'THP_FAULT_FALLBACK'; did you mean 'VM_FAULT_FALLBACK'?
                   count_vm_event(THP_FAULT_FALLBACK);
                                  ^~~~~~~~~~~~~~~~~~
                                  VM_FAULT_FALLBACK
   include/linux/mm_types.h:1219:2: note: 'VM_FAULT_FALLBACK' declared here
           VM_FAULT_FALLBACK       = (__force vm_fault_t)0x000800,
           ^
   mm/shmem.c:2278:18: warning: implicit conversion from enumeration type 'enum vm_fault_reason' to different enumeration type 'enum vm_event_item' [-Wenum-conversion]
                   count_vm_event(THP_FAULT_FALLBACK);
                   ~~~~~~~~~~~~~~ ^~~~~~~~~~~~~~~~~~
>> mm/shmem.c:2283:2: error: call to undeclared function 'page_remove_rmap'; ISO C99 and later do not support implicit function declarations [-Werror,-Wimplicit-function-declaration]
           page_remove_rmap(&old_folio->page, vma, true);
           ^
   mm/shmem.c:2283:2: note: did you mean 'hugetlb_remove_rmap'?
   include/linux/rmap.h:311:20: note: 'hugetlb_remove_rmap' declared here
   static inline void hugetlb_remove_rmap(struct folio *folio)
                      ^
>> mm/shmem.c:2291:10: error: call to undeclared function 'mk_huge_pmd'; ISO C99 and later do not support implicit function declarations [-Werror,-Wimplicit-function-declaration]
           entry = mk_huge_pmd(&new_folio->page, vma->vm_page_prot);
                   ^
>> mm/shmem.c:2292:28: error: call to undeclared function 'pmd_mkdirty'; ISO C99 and later do not support implicit function declarations [-Werror,-Wimplicit-function-declaration]
           entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma);
                                     ^
>> mm/shmem.c:2294:2: error: call to undeclared function 'page_add_file_rmap'; ISO C99 and later do not support implicit function declarations [-Werror,-Wimplicit-function-declaration]
           page_add_file_rmap(&new_folio->page, vma, true);
           ^
   mm/shmem.c:2294:2: note: did you mean 'hugetlb_add_file_rmap'?
   include/linux/rmap.h:303:20: note: 'hugetlb_add_file_rmap' declared here
   static inline void hugetlb_add_file_rmap(struct folio *folio)
                      ^
>> mm/shmem.c:2295:2: error: call to undeclared function 'set_pmd_at'; ISO C99 and later do not support implicit function declarations [-Werror,-Wimplicit-function-declaration]
           set_pmd_at(vma->vm_mm, haddr, vmf->pmd, entry);
           ^
>> mm/shmem.c:2301:2: error: call to undeclared function 'copy_user_large_folio'; ISO C99 and later do not support implicit function declarations [-Werror,-Wimplicit-function-declaration]
           copy_user_large_folio(new_folio, old_folio, haddr, vma);
           ^
   1 warning and 7 errors generated.


vim +/page_remove_rmap +2283 mm/shmem.c

  2239	
  2240	static vm_fault_t shmem_huge_fault(struct vm_fault *vmf, pmd_t orig_pmd)
  2241	{
  2242		vm_fault_t ret = VM_FAULT_FALLBACK;
  2243		unsigned long haddr = vmf->address & HPAGE_PMD_MASK;
  2244		struct folio *old_folio, *new_folio;
  2245		pmd_t entry;
  2246		int gfp_flags = GFP_HIGHUSER_MOVABLE | __GFP_COMP;
  2247		struct vm_area_struct *vma = vmf->vma;
  2248		struct shmem_sb_info *sbinfo = NULL;
  2249		struct inode *inode = file_inode(vma->vm_file);
  2250		struct shmem_inode_info *info = SHMEM_I(inode);
  2251	
  2252		sbinfo = SHMEM_SB(info->vfs_inode.i_sb);
  2253	
  2254		if (sbinfo->no_split == 0)
  2255			return VM_FAULT_FALLBACK;
  2256	
  2257		/* ShmemPmdMapped in tmpfs will not split huge pmd */
  2258		if (!(vmf->flags & FAULT_FLAG_WRITE)
  2259				|| (vma->vm_flags & VM_SHARED))
  2260			return VM_FAULT_FALLBACK;
  2261	
  2262		new_folio = vma_alloc_folio(gfp_flags, HPAGE_PMD_ORDER,
  2263				vmf->vma, haddr, true);
  2264		if (!new_folio)
  2265			ret = VM_FAULT_FALLBACK;
  2266	
  2267		vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd);
  2268		if (pmd_none(*vmf->pmd)) {
  2269			ret = VM_FAULT_FALLBACK;
  2270			goto out;
  2271		}
  2272		if (!pmd_same(*vmf->pmd, orig_pmd)) {
  2273			ret = 0;
  2274			goto out;
  2275		}
  2276	
  2277		if (!new_folio) {
> 2278			count_vm_event(THP_FAULT_FALLBACK);
  2279			ret = VM_FAULT_FALLBACK;
  2280			goto out;
  2281		}
  2282		old_folio = page_folio(pmd_page(*vmf->pmd));
> 2283		page_remove_rmap(&old_folio->page, vma, true);
  2284		pmdp_huge_clear_flush(vma, haddr, vmf->pmd);
  2285	
  2286		__folio_set_locked(new_folio);
  2287		__folio_set_swapbacked(new_folio);
  2288		__folio_mark_uptodate(new_folio);
  2289	
  2290		flush_icache_pages(vma, &new_folio->page, HPAGE_PMD_NR);
> 2291		entry = mk_huge_pmd(&new_folio->page, vma->vm_page_prot);
> 2292		entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma);
  2293	
> 2294		page_add_file_rmap(&new_folio->page, vma, true);
> 2295		set_pmd_at(vma->vm_mm, haddr, vmf->pmd, entry);
  2296		update_mmu_cache_pmd(vma, haddr, vmf->pmd);
  2297		count_vm_event(THP_FILE_MAPPED);
  2298	
  2299		folio_unlock(new_folio);
  2300		spin_unlock(vmf->ptl);
> 2301		copy_user_large_folio(new_folio, old_folio, haddr, vma);
  2302		folio_put(old_folio);
  2303		ret = 0;
  2304		return ret;
  2305	
  2306	out:
  2307		if (new_folio)
  2308			folio_put(new_folio);
  2309		spin_unlock(vmf->ptl);
  2310		return ret;
  2311	}
  2312	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

Re: [PATCH] support tmpfs hugepage PMD is not split when COW

[kernel test robot]

Hi Chen,

kernel test robot noticed the following build errors:

[auto build test ERROR on akpm-mm/mm-everything]
[also build test ERROR on linus/master v6.7 next-20240110]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Chen-Haixiang/support-tmpfs-hugepage-PMD-is-not-split-when-COW/20240110-172314
base:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
patch link:    https://lore.kernel.org/r/20240110092028.1777-1-chenhaixiang3%40huawei.com
patch subject: [PATCH] support tmpfs hugepage PMD is not split when COW
config: arm64-randconfig-002-20240110 (https://download.01.org/0day-ci/archive/20240111/202401110924.z8NSGZ0Z-lkp@intel.com/config)
compiler: clang version 18.0.0git (https://github.com/llvm/llvm-project 7388b7422f9307dd5ae3fe3876a676d83d702daf)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240111/202401110924.z8NSGZ0Z-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202401110924.z8NSGZ0Z-lkp@intel.com/

All errors (new ones prefixed by >>):

   mm/shmem.c:2278:18: error: use of undeclared identifier 'THP_FAULT_FALLBACK'; did you mean 'VM_FAULT_FALLBACK'?
    2278 |                 count_vm_event(THP_FAULT_FALLBACK);
         |                                ^~~~~~~~~~~~~~~~~~
         |                                VM_FAULT_FALLBACK
   include/linux/mm_types.h:1219:2: note: 'VM_FAULT_FALLBACK' declared here
    1219 |         VM_FAULT_FALLBACK       = (__force vm_fault_t)0x000800,
         |         ^
   mm/shmem.c:2278:18: warning: implicit conversion from enumeration type 'enum vm_fault_reason' to different enumeration type 'enum vm_event_item' [-Wenum-conversion]
    2278 |                 count_vm_event(THP_FAULT_FALLBACK);
         |                 ~~~~~~~~~~~~~~ ^~~~~~~~~~~~~~~~~~
   mm/shmem.c:2283:2: error: call to undeclared function 'page_remove_rmap'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
    2283 |         page_remove_rmap(&old_folio->page, vma, true);
         |         ^
   mm/shmem.c:2283:2: note: did you mean 'hugetlb_remove_rmap'?
   include/linux/rmap.h:311:20: note: 'hugetlb_remove_rmap' declared here
     311 | static inline void hugetlb_remove_rmap(struct folio *folio)
         |                    ^
   mm/shmem.c:2291:10: error: call to undeclared function 'mk_huge_pmd'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
    2291 |         entry = mk_huge_pmd(&new_folio->page, vma->vm_page_prot);
         |                 ^
   mm/shmem.c:2291:10: note: did you mean 'mk_huge_pte'?
   include/asm-generic/hugetlb.h:8:21: note: 'mk_huge_pte' declared here
       8 | static inline pte_t mk_huge_pte(struct page *page, pgprot_t pgprot)
         |                     ^
>> mm/shmem.c:2291:8: error: assigning to 'pmd_t' from incompatible type 'int'
    2291 |         entry = mk_huge_pmd(&new_folio->page, vma->vm_page_prot);
         |               ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   mm/shmem.c:2294:2: error: call to undeclared function 'page_add_file_rmap'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
    2294 |         page_add_file_rmap(&new_folio->page, vma, true);
         |         ^
   mm/shmem.c:2294:2: note: did you mean 'hugetlb_add_file_rmap'?
   include/linux/rmap.h:303:20: note: 'hugetlb_add_file_rmap' declared here
     303 | static inline void hugetlb_add_file_rmap(struct folio *folio)
         |                    ^
   1 warning and 5 errors generated.


vim +2291 mm/shmem.c

  2239	
  2240	static vm_fault_t shmem_huge_fault(struct vm_fault *vmf, pmd_t orig_pmd)
  2241	{
  2242		vm_fault_t ret = VM_FAULT_FALLBACK;
  2243		unsigned long haddr = vmf->address & HPAGE_PMD_MASK;
  2244		struct folio *old_folio, *new_folio;
  2245		pmd_t entry;
  2246		int gfp_flags = GFP_HIGHUSER_MOVABLE | __GFP_COMP;
  2247		struct vm_area_struct *vma = vmf->vma;
  2248		struct shmem_sb_info *sbinfo = NULL;
  2249		struct inode *inode = file_inode(vma->vm_file);
  2250		struct shmem_inode_info *info = SHMEM_I(inode);
  2251	
  2252		sbinfo = SHMEM_SB(info->vfs_inode.i_sb);
  2253	
  2254		if (sbinfo->no_split == 0)
  2255			return VM_FAULT_FALLBACK;
  2256	
  2257		/* ShmemPmdMapped in tmpfs will not split huge pmd */
  2258		if (!(vmf->flags & FAULT_FLAG_WRITE)
  2259				|| (vma->vm_flags & VM_SHARED))
  2260			return VM_FAULT_FALLBACK;
  2261	
  2262		new_folio = vma_alloc_folio(gfp_flags, HPAGE_PMD_ORDER,
  2263				vmf->vma, haddr, true);
  2264		if (!new_folio)
  2265			ret = VM_FAULT_FALLBACK;
  2266	
  2267		vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd);
  2268		if (pmd_none(*vmf->pmd)) {
  2269			ret = VM_FAULT_FALLBACK;
  2270			goto out;
  2271		}
  2272		if (!pmd_same(*vmf->pmd, orig_pmd)) {
  2273			ret = 0;
  2274			goto out;
  2275		}
  2276	
  2277		if (!new_folio) {
  2278			count_vm_event(THP_FAULT_FALLBACK);
  2279			ret = VM_FAULT_FALLBACK;
  2280			goto out;
  2281		}
  2282		old_folio = page_folio(pmd_page(*vmf->pmd));
  2283		page_remove_rmap(&old_folio->page, vma, true);
  2284		pmdp_huge_clear_flush(vma, haddr, vmf->pmd);
  2285	
  2286		__folio_set_locked(new_folio);
  2287		__folio_set_swapbacked(new_folio);
  2288		__folio_mark_uptodate(new_folio);
  2289	
  2290		flush_icache_pages(vma, &new_folio->page, HPAGE_PMD_NR);
> 2291		entry = mk_huge_pmd(&new_folio->page, vma->vm_page_prot);
  2292		entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma);
  2293	
  2294		page_add_file_rmap(&new_folio->page, vma, true);
  2295		set_pmd_at(vma->vm_mm, haddr, vmf->pmd, entry);
  2296		update_mmu_cache_pmd(vma, haddr, vmf->pmd);
  2297		count_vm_event(THP_FILE_MAPPED);
  2298	
  2299		folio_unlock(new_folio);
  2300		spin_unlock(vmf->ptl);
  2301		copy_user_large_folio(new_folio, old_folio, haddr, vma);
  2302		folio_put(old_folio);
  2303		ret = 0;
  2304		return ret;
  2305	
  2306	out:
  2307		if (new_folio)
  2308			folio_put(new_folio);
  2309		spin_unlock(vmf->ptl);
  2310		return ret;
  2311	}
  2312	

-- 
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