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Message-ID: <148545058784.17912.6353162518188733642.stgit@djiang5-desk3.ch.intel.com>
Date: Thu, 26 Jan 2017 10:09:47 -0700
From: Dave Jiang <dave.jiang@...el.com>
To: akpm@...ux-foundation.org
Cc: dave.hansen@...ux.intel.com, mawilcox@...rosoft.com,
linux-nvdimm@...ts.01.org, linux-xfs@...r.kernel.org,
linux-mm@...ck.org, vbabka@...e.cz, jack@...e.com,
dan.j.williams@...el.com, linux-ext4@...r.kernel.org,
ross.zwisler@...ux.intel.com, kirill.shutemov@...ux.intel.com
Subject: [PATCH v2 1/3] mm,fs,dax: Change ->pmd_fault to ->huge_fault
In preparation for adding the ability to handle PUD pages, convert
->pmd_fault to ->huge_fault. The vm_fault structure is extended to
include a union of the different page table pointers that may be needed,
and three flag bits are reserved to indicate which type of pointer is in
the union.
[DJ: Forward ported to 4.10-rc]
Signed-off-by: Matthew Wilcox <mawilcox@...rosoft.com>
Signed-off-by: Dave Jiang <dave.jiang@...el.com>
---
drivers/dax/dax.c | 34 +++++++++++++---------------------
fs/dax.c | 43 ++++++++++++++++++++++++++++++-------------
fs/ext2/file.c | 2 +-
fs/ext4/file.c | 6 +++---
fs/xfs/xfs_file.c | 10 +++++-----
fs/xfs/xfs_trace.h | 2 +-
include/linux/dax.h | 6 ------
include/linux/mm.h | 10 +++++++++-
mm/memory.c | 14 ++++++++------
9 files changed, 70 insertions(+), 57 deletions(-)
diff --git a/drivers/dax/dax.c b/drivers/dax/dax.c
index 0261f33..922ec46 100644
--- a/drivers/dax/dax.c
+++ b/drivers/dax/dax.c
@@ -419,7 +419,7 @@ static phys_addr_t pgoff_to_phys(struct dax_dev *dax_dev, pgoff_t pgoff,
return -1;
}
-static int __dax_dev_fault(struct dax_dev *dax_dev, struct vm_fault *vmf)
+static int __dax_dev_pte_fault(struct dax_dev *dax_dev, struct vm_fault *vmf)
{
struct device *dev = &dax_dev->dev;
struct dax_region *dax_region;
@@ -455,23 +455,6 @@ static int __dax_dev_fault(struct dax_dev *dax_dev, struct vm_fault *vmf)
return VM_FAULT_NOPAGE;
}
-static int dax_dev_fault(struct vm_fault *vmf)
-{
- struct vm_area_struct *vma = vmf->vma;
- int rc;
- struct file *filp = vma->vm_file;
- struct dax_dev *dax_dev = filp->private_data;
-
- dev_dbg(&dax_dev->dev, "%s: %s: %s (%#lx - %#lx)\n", __func__,
- current->comm, (vmf->flags & FAULT_FLAG_WRITE)
- ? "write" : "read", vma->vm_start, vma->vm_end);
- rcu_read_lock();
- rc = __dax_dev_fault(dax_dev, vmf);
- rcu_read_unlock();
-
- return rc;
-}
-
static int __dax_dev_pmd_fault(struct dax_dev *dax_dev, struct vm_fault *vmf)
{
unsigned long pmd_addr = vmf->address & PMD_MASK;
@@ -510,7 +493,7 @@ static int __dax_dev_pmd_fault(struct dax_dev *dax_dev, struct vm_fault *vmf)
vmf->flags & FAULT_FLAG_WRITE);
}
-static int dax_dev_pmd_fault(struct vm_fault *vmf)
+static int dax_dev_fault(struct vm_fault *vmf)
{
int rc;
struct file *filp = vmf->vma->vm_file;
@@ -522,7 +505,16 @@ static int dax_dev_pmd_fault(struct vm_fault *vmf)
vmf->vma->vm_start, vmf->vma->vm_end);
rcu_read_lock();
- rc = __dax_dev_pmd_fault(dax_dev, vmf);
+ switch (vmf->flags & FAULT_FLAG_SIZE_MASK) {
+ case FAULT_FLAG_SIZE_PTE:
+ rc = __dax_dev_pte_fault(dax_dev, vmf);
+ break;
+ case FAULT_FLAG_SIZE_PMD:
+ rc = __dax_dev_pmd_fault(dax_dev, vmf);
+ break;
+ default:
+ return VM_FAULT_FALLBACK;
+ }
rcu_read_unlock();
return rc;
@@ -530,7 +522,7 @@ static int dax_dev_pmd_fault(struct vm_fault *vmf)
static const struct vm_operations_struct dax_dev_vm_ops = {
.fault = dax_dev_fault,
- .pmd_fault = dax_dev_pmd_fault,
+ .huge_fault = dax_dev_fault,
};
static int dax_mmap(struct file *filp, struct vm_area_struct *vma)
diff --git a/fs/dax.c b/fs/dax.c
index 7877130..2e90f7a 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -1110,16 +1110,7 @@ static int dax_fault_return(int error)
return VM_FAULT_SIGBUS;
}
-/**
- * dax_iomap_fault - handle a page fault on a DAX file
- * @vmf: The description of the fault
- * @ops: iomap ops passed from the file system
- *
- * When a page fault occurs, filesystems may call this helper in their fault
- * or mkwrite handler for DAX files. Assumes the caller has done all the
- * necessary locking for the page fault to proceed successfully.
- */
-int dax_iomap_fault(struct vm_fault *vmf, struct iomap_ops *ops)
+static int dax_iomap_pte_fault(struct vm_fault *vmf, struct iomap_ops *ops)
{
struct address_space *mapping = vmf->vma->vm_file->f_mapping;
struct inode *inode = mapping->host;
@@ -1236,7 +1227,6 @@ int dax_iomap_fault(struct vm_fault *vmf, struct iomap_ops *ops)
}
return vmf_ret;
}
-EXPORT_SYMBOL_GPL(dax_iomap_fault);
#ifdef CONFIG_FS_DAX_PMD
/*
@@ -1327,7 +1317,7 @@ static int dax_pmd_load_hole(struct vm_fault *vmf, struct iomap *iomap,
return VM_FAULT_FALLBACK;
}
-int dax_iomap_pmd_fault(struct vm_fault *vmf, struct iomap_ops *ops)
+static int dax_iomap_pmd_fault(struct vm_fault *vmf, struct iomap_ops *ops)
{
struct vm_area_struct *vma = vmf->vma;
struct address_space *mapping = vma->vm_file->f_mapping;
@@ -1435,6 +1425,33 @@ int dax_iomap_pmd_fault(struct vm_fault *vmf, struct iomap_ops *ops)
trace_dax_pmd_fault_done(inode, vmf, max_pgoff, result);
return result;
}
-EXPORT_SYMBOL_GPL(dax_iomap_pmd_fault);
+#else
+static int dax_iomap_pmd_fault(struct vm_fault *vmf, struct iomap_ops *ops)
+{
+ return VM_FAULT_FALLBACK;
+}
#endif /* CONFIG_FS_DAX_PMD */
+
+/**
+ * dax_iomap_fault - handle a page fault on a DAX file
+ * @vmf: The description of the fault
+ * @ops: iomap ops passed from the file system
+ *
+ * When a page fault occurs, filesystems may call this helper in
+ * their fault handler for DAX files. dax_iomap_fault() assumes the caller
+ * has done all the necessary locking for page fault to proceed
+ * successfully.
+ */
+int dax_iomap_fault(struct vm_fault *vmf, struct iomap_ops *ops)
+{
+ switch (vmf->flags & FAULT_FLAG_SIZE_MASK) {
+ case FAULT_FLAG_SIZE_PTE:
+ return dax_iomap_pte_fault(vmf, ops);
+ case FAULT_FLAG_SIZE_PMD:
+ return dax_iomap_pmd_fault(vmf, ops);
+ default:
+ return VM_FAULT_FALLBACK;
+ }
+}
+EXPORT_SYMBOL_GPL(dax_iomap_fault);
#endif /* CONFIG_FS_IOMAP */
diff --git a/fs/ext2/file.c b/fs/ext2/file.c
index 0bf0d97..6873883 100644
--- a/fs/ext2/file.c
+++ b/fs/ext2/file.c
@@ -133,7 +133,7 @@ static int ext2_dax_pfn_mkwrite(struct vm_fault *vmf)
static const struct vm_operations_struct ext2_dax_vm_ops = {
.fault = ext2_dax_fault,
/*
- * .pmd_fault is not supported for DAX because allocation in ext2
+ * .huge_fault is not supported for DAX because allocation in ext2
* cannot be reliably aligned to huge page sizes and so pmd faults
* will always fail and fail back to regular faults.
*/
diff --git a/fs/ext4/file.c b/fs/ext4/file.c
index cc0b111..ed22d20 100644
--- a/fs/ext4/file.c
+++ b/fs/ext4/file.c
@@ -276,7 +276,7 @@ static int ext4_dax_fault(struct vm_fault *vmf)
}
static int
-ext4_dax_pmd_fault(struct vm_fault *vmf)
+ext4_dax_huge_fault(struct vm_fault *vmf)
{
int result;
struct inode *inode = file_inode(vmf->vma->vm_file);
@@ -288,7 +288,7 @@ ext4_dax_pmd_fault(struct vm_fault *vmf)
file_update_time(vmf->vma->vm_file);
}
down_read(&EXT4_I(inode)->i_mmap_sem);
- result = dax_iomap_pmd_fault(vmf, &ext4_iomap_ops);
+ result = dax_iomap_fault(vmf, &ext4_iomap_ops);
up_read(&EXT4_I(inode)->i_mmap_sem);
if (write)
sb_end_pagefault(sb);
@@ -328,7 +328,7 @@ static int ext4_dax_pfn_mkwrite(struct vm_fault *vmf)
static const struct vm_operations_struct ext4_dax_vm_ops = {
.fault = ext4_dax_fault,
- .pmd_fault = ext4_dax_pmd_fault,
+ .huge_fault = ext4_dax_fault,
.page_mkwrite = ext4_dax_fault,
.pfn_mkwrite = ext4_dax_pfn_mkwrite,
};
diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index 34e04cf..c4fe261 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -1423,12 +1423,12 @@ xfs_filemap_fault(
/*
* Similar to xfs_filemap_fault(), the DAX fault path can call into here on
* both read and write faults. Hence we need to handle both cases. There is no
- * ->pmd_mkwrite callout for huge pages, so we have a single function here to
+ * ->huge_mkwrite callout for huge pages, so we have a single function here to
* handle both cases here. @flags carries the information on the type of fault
* occuring.
*/
STATIC int
-xfs_filemap_pmd_fault(
+xfs_filemap_huge_fault(
struct vm_fault *vmf)
{
struct inode *inode = file_inode(vmf->vma->vm_file);
@@ -1438,7 +1438,7 @@ xfs_filemap_pmd_fault(
if (!IS_DAX(inode))
return VM_FAULT_FALLBACK;
- trace_xfs_filemap_pmd_fault(ip);
+ trace_xfs_filemap_huge_fault(ip);
if (vmf->flags & FAULT_FLAG_WRITE) {
sb_start_pagefault(inode->i_sb);
@@ -1446,7 +1446,7 @@ xfs_filemap_pmd_fault(
}
xfs_ilock(XFS_I(inode), XFS_MMAPLOCK_SHARED);
- ret = dax_iomap_pmd_fault(vmf, &xfs_iomap_ops);
+ ret = dax_iomap_fault(vmf, &xfs_iomap_ops);
xfs_iunlock(XFS_I(inode), XFS_MMAPLOCK_SHARED);
if (vmf->flags & FAULT_FLAG_WRITE)
@@ -1491,7 +1491,7 @@ xfs_filemap_pfn_mkwrite(
static const struct vm_operations_struct xfs_file_vm_ops = {
.fault = xfs_filemap_fault,
- .pmd_fault = xfs_filemap_pmd_fault,
+ .huge_fault = xfs_filemap_huge_fault,
.map_pages = filemap_map_pages,
.page_mkwrite = xfs_filemap_page_mkwrite,
.pfn_mkwrite = xfs_filemap_pfn_mkwrite,
diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h
index 69c5bcd..719b1d4 100644
--- a/fs/xfs/xfs_trace.h
+++ b/fs/xfs/xfs_trace.h
@@ -687,7 +687,7 @@ DEFINE_INODE_EVENT(xfs_inode_clear_cowblocks_tag);
DEFINE_INODE_EVENT(xfs_inode_free_cowblocks_invalid);
DEFINE_INODE_EVENT(xfs_filemap_fault);
-DEFINE_INODE_EVENT(xfs_filemap_pmd_fault);
+DEFINE_INODE_EVENT(xfs_filemap_huge_fault);
DEFINE_INODE_EVENT(xfs_filemap_page_mkwrite);
DEFINE_INODE_EVENT(xfs_filemap_pfn_mkwrite);
diff --git a/include/linux/dax.h b/include/linux/dax.h
index 4417700..a3bfa26 100644
--- a/include/linux/dax.h
+++ b/include/linux/dax.h
@@ -70,17 +70,11 @@ static inline unsigned int dax_radix_order(void *entry)
return PMD_SHIFT - PAGE_SHIFT;
return 0;
}
-int dax_iomap_pmd_fault(struct vm_fault *vmf, struct iomap_ops *ops);
#else
static inline unsigned int dax_radix_order(void *entry)
{
return 0;
}
-static inline int dax_iomap_pmd_fault(struct vm_fault *vmf,
- struct iomap_ops *ops)
-{
- return VM_FAULT_FALLBACK;
-}
#endif
int dax_pfn_mkwrite(struct vm_fault *vmf);
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 135cc74..19d6f71 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -281,6 +281,11 @@ extern pgprot_t protection_map[16];
#define FAULT_FLAG_REMOTE 0x80 /* faulting for non current tsk/mm */
#define FAULT_FLAG_INSTRUCTION 0x100 /* The fault was during an instruction fetch */
+#define FAULT_FLAG_SIZE_MASK 0x700 /* Support up to 8-level page tables */
+#define FAULT_FLAG_SIZE_PTE 0x000 /* First level (eg 4k) */
+#define FAULT_FLAG_SIZE_PMD 0x100 /* Second level (eg 2MB) */
+#define FAULT_FLAG_SIZE_PUD 0x200 /* Third level (eg 1GB) */
+
#define FAULT_FLAG_TRACE \
{ FAULT_FLAG_WRITE, "WRITE" }, \
{ FAULT_FLAG_MKWRITE, "MKWRITE" }, \
@@ -310,6 +315,9 @@ struct vm_fault {
unsigned long address; /* Faulting virtual address */
pmd_t *pmd; /* Pointer to pmd entry matching
* the 'address' */
+ pud_t *pud; /* Pointer to pud entry matching
+ * the 'address'
+ */
pte_t orig_pte; /* Value of PTE at the time of fault */
struct page *cow_page; /* Page handler may use for COW fault */
@@ -347,7 +355,7 @@ struct vm_operations_struct {
void (*close)(struct vm_area_struct * area);
int (*mremap)(struct vm_area_struct * area);
int (*fault)(struct vm_fault *vmf);
- int (*pmd_fault)(struct vm_fault *vmf);
+ int (*huge_fault)(struct vm_fault *vmf);
void (*map_pages)(struct vm_fault *vmf,
pgoff_t start_pgoff, pgoff_t end_pgoff);
diff --git a/mm/memory.c b/mm/memory.c
index 11f11ae..a2acf9e 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3473,8 +3473,8 @@ static int create_huge_pmd(struct vm_fault *vmf)
{
if (vma_is_anonymous(vmf->vma))
return do_huge_pmd_anonymous_page(vmf);
- if (vmf->vma->vm_ops->pmd_fault)
- return vmf->vma->vm_ops->pmd_fault(vmf);
+ if (vmf->vma->vm_ops->huge_fault)
+ return vmf->vma->vm_ops->huge_fault(vmf);
return VM_FAULT_FALLBACK;
}
@@ -3482,8 +3482,8 @@ static int wp_huge_pmd(struct vm_fault *vmf, pmd_t orig_pmd)
{
if (vma_is_anonymous(vmf->vma))
return do_huge_pmd_wp_page(vmf, orig_pmd);
- if (vmf->vma->vm_ops->pmd_fault)
- return vmf->vma->vm_ops->pmd_fault(vmf);
+ if (vmf->vma->vm_ops->huge_fault)
+ return vmf->vma->vm_ops->huge_fault(vmf);
/* COW handled on pte level: split pmd */
VM_BUG_ON_VMA(vmf->vma->vm_flags & VM_SHARED, vmf->vma);
@@ -3613,6 +3613,7 @@ static int __handle_mm_fault(struct vm_area_struct *vma, unsigned long address,
struct mm_struct *mm = vma->vm_mm;
pgd_t *pgd;
pud_t *pud;
+ int ret;
pgd = pgd_offset(mm, address);
pud = pud_alloc(mm, pgd, address);
@@ -3622,15 +3623,16 @@ static int __handle_mm_fault(struct vm_area_struct *vma, unsigned long address,
if (!vmf.pmd)
return VM_FAULT_OOM;
if (pmd_none(*vmf.pmd) && transparent_hugepage_enabled(vma)) {
- int ret = create_huge_pmd(&vmf);
+ vmf.flags |= FAULT_FLAG_SIZE_PMD;
+ ret = create_huge_pmd(&vmf);
if (!(ret & VM_FAULT_FALLBACK))
return ret;
} else {
pmd_t orig_pmd = *vmf.pmd;
- int ret;
barrier();
if (pmd_trans_huge(orig_pmd) || pmd_devmap(orig_pmd)) {
+ vmf.flags |= FAULT_FLAG_SIZE_PMD;
if (pmd_protnone(orig_pmd) && vma_is_accessible(vma))
return do_huge_pmd_numa_page(&vmf, orig_pmd);
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