* [PATCH 01/10] thp: vma_adjust_trans_huge(): adjust file-backed VMA too
2015-07-10 20:29 [PATCH 00/10] Huge page support for DAX files Matthew Wilcox
@ 2015-07-10 20:29 ` Matthew Wilcox
2015-07-10 20:29 ` [PATCH 02/10] dax: Move DAX-related functions to a new header Matthew Wilcox
` (8 subsequent siblings)
9 siblings, 0 replies; 16+ messages in thread
From: Matthew Wilcox @ 2015-07-10 20:29 UTC (permalink / raw)
To: linux-fsdevel, linux-kernel, linux-mm; +Cc: Kirill A. Shutemov, willy
From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Since we're going to have huge pages in page cache, we need to call
adjust file-backed VMA, which potentially can contain huge pages.
For now we call it for all VMAs.
Probably later we will need to introduce a flag to indicate that the VMA
has huge pages.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Hillf Danton <dhillf@gmail.com>
---
include/linux/huge_mm.h | 11 +----------
mm/huge_memory.c | 2 +-
2 files changed, 2 insertions(+), 11 deletions(-)
diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
index f10b20f..1c53c7d 100644
--- a/include/linux/huge_mm.h
+++ b/include/linux/huge_mm.h
@@ -122,7 +122,7 @@ extern void split_huge_page_pmd_mm(struct mm_struct *mm, unsigned long address,
#endif
extern int hugepage_madvise(struct vm_area_struct *vma,
unsigned long *vm_flags, int advice);
-extern void __vma_adjust_trans_huge(struct vm_area_struct *vma,
+extern void vma_adjust_trans_huge(struct vm_area_struct *vma,
unsigned long start,
unsigned long end,
long adjust_next);
@@ -138,15 +138,6 @@ static inline int pmd_trans_huge_lock(pmd_t *pmd, struct vm_area_struct *vma,
else
return 0;
}
-static inline void vma_adjust_trans_huge(struct vm_area_struct *vma,
- unsigned long start,
- unsigned long end,
- long adjust_next)
-{
- if (!vma->anon_vma || vma->vm_ops)
- return;
- __vma_adjust_trans_huge(vma, start, end, adjust_next);
-}
static inline int hpage_nr_pages(struct page *page)
{
if (unlikely(PageTransHuge(page)))
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index c107094..911071b 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2967,7 +2967,7 @@ static void split_huge_page_address(struct mm_struct *mm,
split_huge_page_pmd_mm(mm, address, pmd);
}
-void __vma_adjust_trans_huge(struct vm_area_struct *vma,
+void vma_adjust_trans_huge(struct vm_area_struct *vma,
unsigned long start,
unsigned long end,
long adjust_next)
--
2.1.4
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^ permalink raw reply related [flat|nested] 16+ messages in thread* [PATCH 02/10] dax: Move DAX-related functions to a new header
2015-07-10 20:29 [PATCH 00/10] Huge page support for DAX files Matthew Wilcox
2015-07-10 20:29 ` [PATCH 01/10] thp: vma_adjust_trans_huge(): adjust file-backed VMA too Matthew Wilcox
@ 2015-07-10 20:29 ` Matthew Wilcox
2015-07-10 20:29 ` [PATCH 03/10] thp: Prepare for DAX huge pages Matthew Wilcox
` (7 subsequent siblings)
9 siblings, 0 replies; 16+ messages in thread
From: Matthew Wilcox @ 2015-07-10 20:29 UTC (permalink / raw)
To: linux-fsdevel, linux-kernel, linux-mm; +Cc: Matthew Wilcox
From: Matthew Wilcox <willy@linux.intel.com>
In order to handle the !CONFIG_TRANSPARENT_HUGEPAGES case, we need to
return VM_FAULT_FALLBACK from the inlined dax_pmd_fault(), which is
defined in linux/mm.h. Given that we don't want to include <linux/mm.h>
in <linux/fs.h>, the easiest solution is to move the DAX-related functions
to a new header, <linux/dax.h>. We could also have moved VM_FAULT_*
definitions to a new header, or a different header that isn't quite
such a boil-the-ocean header as <linux/mm.h>, but this felt like the
best option.
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
---
fs/block_dev.c | 1 +
fs/ext2/file.c | 1 +
fs/ext2/inode.c | 1 +
fs/ext4/file.c | 1 +
fs/ext4/indirect.c | 1 +
fs/ext4/inode.c | 1 +
fs/xfs/xfs_buf.h | 1 +
include/linux/dax.h | 21 +++++++++++++++++++++
include/linux/fs.h | 14 --------------
9 files changed, 28 insertions(+), 14 deletions(-)
create mode 100644 include/linux/dax.h
diff --git a/fs/block_dev.c b/fs/block_dev.c
index 1982437..9be2d7e 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -28,6 +28,7 @@
#include <linux/namei.h>
#include <linux/log2.h>
#include <linux/cleancache.h>
+#include <linux/dax.h>
#include <asm/uaccess.h>
#include "internal.h"
diff --git a/fs/ext2/file.c b/fs/ext2/file.c
index 3b57c9f..db4c299 100644
--- a/fs/ext2/file.c
+++ b/fs/ext2/file.c
@@ -20,6 +20,7 @@
#include <linux/time.h>
#include <linux/pagemap.h>
+#include <linux/dax.h>
#include <linux/quotaops.h>
#include "ext2.h"
#include "xattr.h"
diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c
index 27c85ea..1488248 100644
--- a/fs/ext2/inode.c
+++ b/fs/ext2/inode.c
@@ -25,6 +25,7 @@
#include <linux/time.h>
#include <linux/highuid.h>
#include <linux/pagemap.h>
+#include <linux/dax.h>
#include <linux/quotaops.h>
#include <linux/writeback.h>
#include <linux/buffer_head.h>
diff --git a/fs/ext4/file.c b/fs/ext4/file.c
index e5bdcb7..34d814f 100644
--- a/fs/ext4/file.c
+++ b/fs/ext4/file.c
@@ -22,6 +22,7 @@
#include <linux/fs.h>
#include <linux/mount.h>
#include <linux/path.h>
+#include <linux/dax.h>
#include <linux/quotaops.h>
#include <linux/pagevec.h>
#include <linux/uio.h>
diff --git a/fs/ext4/indirect.c b/fs/ext4/indirect.c
index 4f6ac49..2468261 100644
--- a/fs/ext4/indirect.c
+++ b/fs/ext4/indirect.c
@@ -22,6 +22,7 @@
#include "ext4_jbd2.h"
#include "truncate.h"
+#include <linux/dax.h>
#include <linux/uio.h>
#include <trace/events/ext4.h>
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index ae54de4..26a32da 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -22,6 +22,7 @@
#include <linux/time.h>
#include <linux/highuid.h>
#include <linux/pagemap.h>
+#include <linux/dax.h>
#include <linux/quotaops.h>
#include <linux/string.h>
#include <linux/buffer_head.h>
diff --git a/fs/xfs/xfs_buf.h b/fs/xfs/xfs_buf.h
index 331c1cc..c79b717 100644
--- a/fs/xfs/xfs_buf.h
+++ b/fs/xfs/xfs_buf.h
@@ -23,6 +23,7 @@
#include <linux/spinlock.h>
#include <linux/mm.h>
#include <linux/fs.h>
+#include <linux/dax.h>
#include <linux/buffer_head.h>
#include <linux/uio.h>
#include <linux/list_lru.h>
diff --git a/include/linux/dax.h b/include/linux/dax.h
new file mode 100644
index 0000000..4f27d3d
--- /dev/null
+++ b/include/linux/dax.h
@@ -0,0 +1,21 @@
+#ifndef _LINUX_DAX_H
+#define _LINUX_DAX_H
+
+#include <linux/fs.h>
+#include <linux/mm.h>
+#include <asm/pgtable.h>
+
+ssize_t dax_do_io(struct kiocb *, struct inode *, struct iov_iter *, loff_t,
+ get_block_t, dio_iodone_t, int flags);
+int dax_clear_blocks(struct inode *, sector_t block, long size);
+int dax_zero_page_range(struct inode *, loff_t from, unsigned len, get_block_t);
+int dax_truncate_page(struct inode *, loff_t from, get_block_t);
+int dax_fault(struct vm_area_struct *, struct vm_fault *, get_block_t,
+ dax_iodone_t);
+int __dax_fault(struct vm_area_struct *, struct vm_fault *, get_block_t,
+ dax_iodone_t);
+int dax_pfn_mkwrite(struct vm_area_struct *, struct vm_fault *);
+#define dax_mkwrite(vma, vmf, gb, iod) dax_fault(vma, vmf, gb, iod)
+#define __dax_mkwrite(vma, vmf, gb, iod) __dax_fault(vma, vmf, gb, iod)
+
+#endif
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 47053b3..824102a 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -51,7 +51,6 @@ struct swap_info_struct;
struct seq_file;
struct workqueue_struct;
struct iov_iter;
-struct vm_fault;
extern void __init inode_init(void);
extern void __init inode_init_early(void);
@@ -2656,19 +2655,6 @@ extern loff_t fixed_size_llseek(struct file *file, loff_t offset,
extern int generic_file_open(struct inode * inode, struct file * filp);
extern int nonseekable_open(struct inode * inode, struct file * filp);
-ssize_t dax_do_io(struct kiocb *, struct inode *, struct iov_iter *, loff_t,
- get_block_t, dio_iodone_t, int flags);
-int dax_clear_blocks(struct inode *, sector_t block, long size);
-int dax_zero_page_range(struct inode *, loff_t from, unsigned len, get_block_t);
-int dax_truncate_page(struct inode *, loff_t from, get_block_t);
-int dax_fault(struct vm_area_struct *, struct vm_fault *, get_block_t,
- dax_iodone_t);
-int __dax_fault(struct vm_area_struct *, struct vm_fault *, get_block_t,
- dax_iodone_t);
-int dax_pfn_mkwrite(struct vm_area_struct *, struct vm_fault *);
-#define dax_mkwrite(vma, vmf, gb, iod) dax_fault(vma, vmf, gb, iod)
-#define __dax_mkwrite(vma, vmf, gb, iod) __dax_fault(vma, vmf, gb, iod)
-
#ifdef CONFIG_BLOCK
typedef void (dio_submit_t)(int rw, struct bio *bio, struct inode *inode,
loff_t file_offset);
--
2.1.4
--
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^ permalink raw reply related [flat|nested] 16+ messages in thread* [PATCH 03/10] thp: Prepare for DAX huge pages
2015-07-10 20:29 [PATCH 00/10] Huge page support for DAX files Matthew Wilcox
2015-07-10 20:29 ` [PATCH 01/10] thp: vma_adjust_trans_huge(): adjust file-backed VMA too Matthew Wilcox
2015-07-10 20:29 ` [PATCH 02/10] dax: Move DAX-related functions to a new header Matthew Wilcox
@ 2015-07-10 20:29 ` Matthew Wilcox
2015-07-19 11:03 ` Kirill A. Shutemov
2015-07-10 20:29 ` [PATCH 04/10] mm: Add a pmd_fault handler Matthew Wilcox
` (6 subsequent siblings)
9 siblings, 1 reply; 16+ messages in thread
From: Matthew Wilcox @ 2015-07-10 20:29 UTC (permalink / raw)
To: linux-fsdevel, linux-kernel, linux-mm; +Cc: Matthew Wilcox
From: Matthew Wilcox <willy@linux.intel.com>
Add a vma_is_dax() helper macro to test whether the VMA is DAX, and use
it in zap_huge_pmd() and __split_huge_page_pmd().
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
---
include/linux/dax.h | 4 ++++
mm/huge_memory.c | 46 ++++++++++++++++++++++++++++------------------
2 files changed, 32 insertions(+), 18 deletions(-)
diff --git a/include/linux/dax.h b/include/linux/dax.h
index 4f27d3d..9b51f9d 100644
--- a/include/linux/dax.h
+++ b/include/linux/dax.h
@@ -18,4 +18,8 @@ int dax_pfn_mkwrite(struct vm_area_struct *, struct vm_fault *);
#define dax_mkwrite(vma, vmf, gb, iod) dax_fault(vma, vmf, gb, iod)
#define __dax_mkwrite(vma, vmf, gb, iod) __dax_fault(vma, vmf, gb, iod)
+static inline bool vma_is_dax(struct vm_area_struct *vma)
+{
+ return vma->vm_file && IS_DAX(vma->vm_file->f_mapping->host);
+}
#endif
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 911071b..b7bd855 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -23,6 +23,7 @@
#include <linux/pagemap.h>
#include <linux/migrate.h>
#include <linux/hashtable.h>
+#include <linux/dax.h>
#include <asm/tlb.h>
#include <asm/pgalloc.h>
@@ -1391,7 +1392,6 @@ int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
int ret = 0;
if (__pmd_trans_huge_lock(pmd, vma, &ptl) == 1) {
- struct page *page;
pgtable_t pgtable;
pmd_t orig_pmd;
/*
@@ -1403,13 +1403,22 @@ int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
orig_pmd = pmdp_huge_get_and_clear_full(tlb->mm, addr, pmd,
tlb->fullmm);
tlb_remove_pmd_tlb_entry(tlb, pmd, addr);
- pgtable = pgtable_trans_huge_withdraw(tlb->mm, pmd);
+ if (vma_is_dax(vma)) {
+ if (is_huge_zero_pmd(orig_pmd)) {
+ pgtable = NULL;
+ } else {
+ spin_unlock(ptl);
+ return 1;
+ }
+ } else {
+ pgtable = pgtable_trans_huge_withdraw(tlb->mm, pmd);
+ }
if (is_huge_zero_pmd(orig_pmd)) {
atomic_long_dec(&tlb->mm->nr_ptes);
spin_unlock(ptl);
put_huge_zero_page();
} else {
- page = pmd_page(orig_pmd);
+ struct page *page = pmd_page(orig_pmd);
page_remove_rmap(page);
VM_BUG_ON_PAGE(page_mapcount(page) < 0, page);
add_mm_counter(tlb->mm, MM_ANONPAGES, -HPAGE_PMD_NR);
@@ -1418,7 +1427,8 @@ int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
spin_unlock(ptl);
tlb_remove_page(tlb, page);
}
- pte_free(tlb->mm, pgtable);
+ if (pgtable)
+ pte_free(tlb->mm, pgtable);
ret = 1;
}
return ret;
@@ -2887,7 +2897,7 @@ void __split_huge_page_pmd(struct vm_area_struct *vma, unsigned long address,
pmd_t *pmd)
{
spinlock_t *ptl;
- struct page *page;
+ struct page *page = NULL;
struct mm_struct *mm = vma->vm_mm;
unsigned long haddr = address & HPAGE_PMD_MASK;
unsigned long mmun_start; /* For mmu_notifiers */
@@ -2900,25 +2910,25 @@ void __split_huge_page_pmd(struct vm_area_struct *vma, unsigned long address,
again:
mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
ptl = pmd_lock(mm, pmd);
- if (unlikely(!pmd_trans_huge(*pmd))) {
- spin_unlock(ptl);
- mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
- return;
- }
- if (is_huge_zero_pmd(*pmd)) {
+ if (unlikely(!pmd_trans_huge(*pmd)))
+ goto unlock;
+ if (vma_is_dax(vma)) {
+ pmdp_huge_clear_flush(vma, haddr, pmd);
+ } else if (is_huge_zero_pmd(*pmd)) {
__split_huge_zero_page_pmd(vma, haddr, pmd);
- spin_unlock(ptl);
- mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
- return;
+ } else {
+ page = pmd_page(*pmd);
+ VM_BUG_ON_PAGE(!page_count(page), page);
+ get_page(page);
}
- page = pmd_page(*pmd);
- VM_BUG_ON_PAGE(!page_count(page), page);
- get_page(page);
+ unlock:
spin_unlock(ptl);
mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
- split_huge_page(page);
+ if (!page)
+ return;
+ split_huge_page(page);
put_page(page);
/*
--
2.1.4
--
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^ permalink raw reply related [flat|nested] 16+ messages in thread* Re: [PATCH 03/10] thp: Prepare for DAX huge pages
2015-07-10 20:29 ` [PATCH 03/10] thp: Prepare for DAX huge pages Matthew Wilcox
@ 2015-07-19 11:03 ` Kirill A. Shutemov
0 siblings, 0 replies; 16+ messages in thread
From: Kirill A. Shutemov @ 2015-07-19 11:03 UTC (permalink / raw)
To: Matthew Wilcox; +Cc: linux-fsdevel, linux-kernel, linux-mm, Matthew Wilcox
On Fri, Jul 10, 2015 at 04:29:18PM -0400, Matthew Wilcox wrote:
> From: Matthew Wilcox <willy@linux.intel.com>
>
> Add a vma_is_dax() helper macro to test whether the VMA is DAX, and use
> it in zap_huge_pmd() and __split_huge_page_pmd().
>
> Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
> ---
> include/linux/dax.h | 4 ++++
> mm/huge_memory.c | 46 ++++++++++++++++++++++++++++------------------
> 2 files changed, 32 insertions(+), 18 deletions(-)
>
> diff --git a/include/linux/dax.h b/include/linux/dax.h
> index 4f27d3d..9b51f9d 100644
> --- a/include/linux/dax.h
> +++ b/include/linux/dax.h
> @@ -18,4 +18,8 @@ int dax_pfn_mkwrite(struct vm_area_struct *, struct vm_fault *);
> #define dax_mkwrite(vma, vmf, gb, iod) dax_fault(vma, vmf, gb, iod)
> #define __dax_mkwrite(vma, vmf, gb, iod) __dax_fault(vma, vmf, gb, iod)
>
> +static inline bool vma_is_dax(struct vm_area_struct *vma)
> +{
> + return vma->vm_file && IS_DAX(vma->vm_file->f_mapping->host);
> +}
> #endif
> diff --git a/mm/huge_memory.c b/mm/huge_memory.c
> index 911071b..b7bd855 100644
> --- a/mm/huge_memory.c
> +++ b/mm/huge_memory.c
> @@ -23,6 +23,7 @@
> #include <linux/pagemap.h>
> #include <linux/migrate.h>
> #include <linux/hashtable.h>
> +#include <linux/dax.h>
>
> #include <asm/tlb.h>
> #include <asm/pgalloc.h>
> @@ -1391,7 +1392,6 @@ int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
> int ret = 0;
>
> if (__pmd_trans_huge_lock(pmd, vma, &ptl) == 1) {
> - struct page *page;
> pgtable_t pgtable;
> pmd_t orig_pmd;
> /*
> @@ -1403,13 +1403,22 @@ int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
> orig_pmd = pmdp_huge_get_and_clear_full(tlb->mm, addr, pmd,
> tlb->fullmm);
> tlb_remove_pmd_tlb_entry(tlb, pmd, addr);
> - pgtable = pgtable_trans_huge_withdraw(tlb->mm, pmd);
> + if (vma_is_dax(vma)) {
> + if (is_huge_zero_pmd(orig_pmd)) {
> + pgtable = NULL;
pgtable_t is not always a pointer. See arch/arc.
> + } else {
> + spin_unlock(ptl);
> + return 1;
> + }
> + } else {
> + pgtable = pgtable_trans_huge_withdraw(tlb->mm, pmd);
> + }
> if (is_huge_zero_pmd(orig_pmd)) {
> atomic_long_dec(&tlb->mm->nr_ptes);
> spin_unlock(ptl);
> put_huge_zero_page();
> } else {
> - page = pmd_page(orig_pmd);
> + struct page *page = pmd_page(orig_pmd);
> page_remove_rmap(page);
> VM_BUG_ON_PAGE(page_mapcount(page) < 0, page);
> add_mm_counter(tlb->mm, MM_ANONPAGES, -HPAGE_PMD_NR);
> @@ -1418,7 +1427,8 @@ int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
> spin_unlock(ptl);
> tlb_remove_page(tlb, page);
> }
> - pte_free(tlb->mm, pgtable);
> + if (pgtable)
> + pte_free(tlb->mm, pgtable);
It's better to drop "pgtable = NULL;" above and use "if (vma_is_dax(vma))"
here.
> ret = 1;
> }
> return ret;
> @@ -2887,7 +2897,7 @@ void __split_huge_page_pmd(struct vm_area_struct *vma, unsigned long address,
> pmd_t *pmd)
> {
> spinlock_t *ptl;
> - struct page *page;
> + struct page *page = NULL;
> struct mm_struct *mm = vma->vm_mm;
> unsigned long haddr = address & HPAGE_PMD_MASK;
> unsigned long mmun_start; /* For mmu_notifiers */
> @@ -2900,25 +2910,25 @@ void __split_huge_page_pmd(struct vm_area_struct *vma, unsigned long address,
> again:
> mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
> ptl = pmd_lock(mm, pmd);
> - if (unlikely(!pmd_trans_huge(*pmd))) {
> - spin_unlock(ptl);
> - mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
> - return;
> - }
> - if (is_huge_zero_pmd(*pmd)) {
> + if (unlikely(!pmd_trans_huge(*pmd)))
> + goto unlock;
> + if (vma_is_dax(vma)) {
> + pmdp_huge_clear_flush(vma, haddr, pmd);
pmdp_huge_clear_flush_notify()
> + } else if (is_huge_zero_pmd(*pmd)) {
> __split_huge_zero_page_pmd(vma, haddr, pmd);
> - spin_unlock(ptl);
> - mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
> - return;
> + } else {
> + page = pmd_page(*pmd);
> + VM_BUG_ON_PAGE(!page_count(page), page);
> + get_page(page);
> }
> - page = pmd_page(*pmd);
> - VM_BUG_ON_PAGE(!page_count(page), page);
> - get_page(page);
> + unlock:
> spin_unlock(ptl);
> mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
>
> - split_huge_page(page);
> + if (!page)
> + return;
>
> + split_huge_page(page);
> put_page(page);
>
> /*
> --
> 2.1.4
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at http://www.tux.org/lkml/
--
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--
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^ permalink raw reply [flat|nested] 16+ messages in thread
* [PATCH 04/10] mm: Add a pmd_fault handler
2015-07-10 20:29 [PATCH 00/10] Huge page support for DAX files Matthew Wilcox
` (2 preceding siblings ...)
2015-07-10 20:29 ` [PATCH 03/10] thp: Prepare for DAX huge pages Matthew Wilcox
@ 2015-07-10 20:29 ` Matthew Wilcox
2015-07-10 20:29 ` [PATCH 05/10] mm: Export various functions for the benefit of DAX Matthew Wilcox
` (5 subsequent siblings)
9 siblings, 0 replies; 16+ messages in thread
From: Matthew Wilcox @ 2015-07-10 20:29 UTC (permalink / raw)
To: linux-fsdevel, linux-kernel, linux-mm; +Cc: Matthew Wilcox
From: Matthew Wilcox <willy@linux.intel.com>
Allow non-anonymous VMAs to provide huge pages in response to a page fault.
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
---
include/linux/mm.h | 2 ++
mm/memory.c | 30 ++++++++++++++++++++++++------
2 files changed, 26 insertions(+), 6 deletions(-)
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 2e872f9..00473e4 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -246,6 +246,8 @@ struct vm_operations_struct {
void (*open)(struct vm_area_struct * area);
void (*close)(struct vm_area_struct * area);
int (*fault)(struct vm_area_struct *vma, struct vm_fault *vmf);
+ int (*pmd_fault)(struct vm_area_struct *, unsigned long address,
+ pmd_t *, unsigned int flags);
void (*map_pages)(struct vm_area_struct *vma, struct vm_fault *vmf);
/* notification that a previously read-only page is about to become
diff --git a/mm/memory.c b/mm/memory.c
index a84fbb7..32007d6 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3209,6 +3209,27 @@ out:
return 0;
}
+static int create_huge_pmd(struct mm_struct *mm, struct vm_area_struct *vma,
+ unsigned long address, pmd_t *pmd, unsigned int flags)
+{
+ if (!vma->vm_ops)
+ return do_huge_pmd_anonymous_page(mm, vma, address, pmd, flags);
+ if (vma->vm_ops->pmd_fault)
+ return vma->vm_ops->pmd_fault(vma, address, pmd, flags);
+ return VM_FAULT_FALLBACK;
+}
+
+static int wp_huge_pmd(struct mm_struct *mm, struct vm_area_struct *vma,
+ unsigned long address, pmd_t *pmd, pmd_t orig_pmd,
+ unsigned int flags)
+{
+ if (!vma->vm_ops)
+ return do_huge_pmd_wp_page(mm, vma, address, pmd, orig_pmd);
+ if (vma->vm_ops->pmd_fault)
+ return vma->vm_ops->pmd_fault(vma, address, pmd, flags);
+ return VM_FAULT_FALLBACK;
+}
+
/*
* These routines also need to handle stuff like marking pages dirty
* and/or accessed for architectures that don't do it in hardware (most
@@ -3312,10 +3333,7 @@ static int __handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma,
if (!pmd)
return VM_FAULT_OOM;
if (pmd_none(*pmd) && transparent_hugepage_enabled(vma)) {
- int ret = VM_FAULT_FALLBACK;
- if (!vma->vm_ops)
- ret = do_huge_pmd_anonymous_page(mm, vma, address,
- pmd, flags);
+ int ret = create_huge_pmd(mm, vma, address, pmd, flags);
if (!(ret & VM_FAULT_FALLBACK))
return ret;
} else {
@@ -3339,8 +3357,8 @@ static int __handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma,
orig_pmd, pmd);
if (dirty && !pmd_write(orig_pmd)) {
- ret = do_huge_pmd_wp_page(mm, vma, address, pmd,
- orig_pmd);
+ ret = wp_huge_pmd(mm, vma, address, pmd,
+ orig_pmd, flags);
if (!(ret & VM_FAULT_FALLBACK))
return ret;
} else {
--
2.1.4
--
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^ permalink raw reply related [flat|nested] 16+ messages in thread* [PATCH 05/10] mm: Export various functions for the benefit of DAX
2015-07-10 20:29 [PATCH 00/10] Huge page support for DAX files Matthew Wilcox
` (3 preceding siblings ...)
2015-07-10 20:29 ` [PATCH 04/10] mm: Add a pmd_fault handler Matthew Wilcox
@ 2015-07-10 20:29 ` Matthew Wilcox
2015-07-10 20:29 ` [PATCH 06/10] mm: Add vmf_insert_pfn_pmd() Matthew Wilcox
` (4 subsequent siblings)
9 siblings, 0 replies; 16+ messages in thread
From: Matthew Wilcox @ 2015-07-10 20:29 UTC (permalink / raw)
To: linux-fsdevel, linux-kernel, linux-mm; +Cc: Matthew Wilcox
From: Matthew Wilcox <willy@linux.intel.com>
To use the huge zero page in DAX, we need these functions exported.
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
---
include/linux/huge_mm.h | 10 ++++++++++
mm/huge_memory.c | 9 ++-------
2 files changed, 12 insertions(+), 7 deletions(-)
diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
index 1c53c7d..70587ea 100644
--- a/include/linux/huge_mm.h
+++ b/include/linux/huge_mm.h
@@ -155,6 +155,16 @@ static inline bool is_huge_zero_page(struct page *page)
return ACCESS_ONCE(huge_zero_page) == page;
}
+static inline bool is_huge_zero_pmd(pmd_t pmd)
+{
+ return is_huge_zero_page(pmd_page(pmd));
+}
+
+struct page *get_huge_zero_page(void);
+bool set_huge_zero_page(pgtable_t pgtable, struct mm_struct *mm,
+ struct vm_area_struct *vma, unsigned long haddr,
+ pmd_t *pmd, struct page *zero_page);
+
#else /* CONFIG_TRANSPARENT_HUGEPAGE */
#define HPAGE_PMD_SHIFT ({ BUILD_BUG(); 0; })
#define HPAGE_PMD_MASK ({ BUILD_BUG(); 0; })
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index b7bd855..db3180f 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -172,12 +172,7 @@ fail:
static atomic_t huge_zero_refcount;
struct page *huge_zero_page __read_mostly;
-static inline bool is_huge_zero_pmd(pmd_t pmd)
-{
- return is_huge_zero_page(pmd_page(pmd));
-}
-
-static struct page *get_huge_zero_page(void)
+struct page *get_huge_zero_page(void)
{
struct page *zero_page;
retry:
@@ -772,7 +767,7 @@ static inline gfp_t alloc_hugepage_gfpmask(int defrag, gfp_t extra_gfp)
}
/* Caller must hold page table lock. */
-static bool set_huge_zero_page(pgtable_t pgtable, struct mm_struct *mm,
+bool set_huge_zero_page(pgtable_t pgtable, struct mm_struct *mm,
struct vm_area_struct *vma, unsigned long haddr, pmd_t *pmd,
struct page *zero_page)
{
--
2.1.4
--
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^ permalink raw reply related [flat|nested] 16+ messages in thread* [PATCH 06/10] mm: Add vmf_insert_pfn_pmd()
2015-07-10 20:29 [PATCH 00/10] Huge page support for DAX files Matthew Wilcox
` (4 preceding siblings ...)
2015-07-10 20:29 ` [PATCH 05/10] mm: Export various functions for the benefit of DAX Matthew Wilcox
@ 2015-07-10 20:29 ` Matthew Wilcox
2015-07-13 13:23 ` Jeff Moyer
2015-07-10 20:29 ` [PATCH 07/10] dax: Add huge page fault support Matthew Wilcox
` (3 subsequent siblings)
9 siblings, 1 reply; 16+ messages in thread
From: Matthew Wilcox @ 2015-07-10 20:29 UTC (permalink / raw)
To: linux-fsdevel, linux-kernel, linux-mm; +Cc: Matthew Wilcox
From: Matthew Wilcox <willy@linux.intel.com>
Similar to vm_insert_pfn(), but for PMDs rather than PTEs. The 'vmf_'
prefix instead of 'vm_' prefix is intended to indicate that it returns
a VMF_ value rather than an errno (which would only have to be converted
into a VMF_ value anyway).
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
---
include/linux/huge_mm.h | 2 ++
mm/huge_memory.c | 43 +++++++++++++++++++++++++++++++++++++++++++
2 files changed, 45 insertions(+)
diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
index 70587ea..f9b612f 100644
--- a/include/linux/huge_mm.h
+++ b/include/linux/huge_mm.h
@@ -33,6 +33,8 @@ extern int move_huge_pmd(struct vm_area_struct *vma,
extern int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
unsigned long addr, pgprot_t newprot,
int prot_numa);
+int vmf_insert_pfn_pmd(struct vm_area_struct *, unsigned long addr, pmd_t *,
+ unsigned long pfn, bool write);
enum transparent_hugepage_flag {
TRANSPARENT_HUGEPAGE_FLAG,
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index db3180f..26d0fc1 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -837,6 +837,49 @@ int do_huge_pmd_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma,
return 0;
}
+static int insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr,
+ pmd_t *pmd, unsigned long pfn, pgprot_t prot, bool write)
+{
+ struct mm_struct *mm = vma->vm_mm;
+ pmd_t entry;
+ spinlock_t *ptl;
+
+ ptl = pmd_lock(mm, pmd);
+ if (pmd_none(*pmd)) {
+ entry = pmd_mkhuge(pfn_pmd(pfn, prot));
+ if (write) {
+ entry = pmd_mkyoung(pmd_mkdirty(entry));
+ entry = maybe_pmd_mkwrite(entry, vma);
+ }
+ set_pmd_at(mm, addr, pmd, entry);
+ update_mmu_cache_pmd(vma, addr, pmd);
+ }
+ spin_unlock(ptl);
+ return VM_FAULT_NOPAGE;
+}
+
+int vmf_insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr,
+ pmd_t *pmd, unsigned long pfn, bool write)
+{
+ pgprot_t pgprot = vma->vm_page_prot;
+ /*
+ * If we had pmd_special, we could avoid all these restrictions,
+ * but we need to be consistent with PTEs and architectures that
+ * can't support a 'special' bit.
+ */
+ BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)));
+ BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) ==
+ (VM_PFNMAP|VM_MIXEDMAP));
+ BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags));
+ BUG_ON((vma->vm_flags & VM_MIXEDMAP) && pfn_valid(pfn));
+
+ if (addr < vma->vm_start || addr >= vma->vm_end)
+ return VM_FAULT_SIGBUS;
+ if (track_pfn_insert(vma, &pgprot, pfn))
+ return VM_FAULT_SIGBUS;
+ return insert_pfn_pmd(vma, addr, pmd, pfn, pgprot, write);
+}
+
int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm,
pmd_t *dst_pmd, pmd_t *src_pmd, unsigned long addr,
struct vm_area_struct *vma)
--
2.1.4
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^ permalink raw reply related [flat|nested] 16+ messages in thread* Re: [PATCH 06/10] mm: Add vmf_insert_pfn_pmd()
2015-07-10 20:29 ` [PATCH 06/10] mm: Add vmf_insert_pfn_pmd() Matthew Wilcox
@ 2015-07-13 13:23 ` Jeff Moyer
2015-07-13 15:02 ` Matthew Wilcox
0 siblings, 1 reply; 16+ messages in thread
From: Jeff Moyer @ 2015-07-13 13:23 UTC (permalink / raw)
To: Matthew Wilcox; +Cc: linux-fsdevel, linux-kernel, linux-mm, Matthew Wilcox
Matthew Wilcox <matthew.r.wilcox@intel.com> writes:
> +static int insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr,
> + pmd_t *pmd, unsigned long pfn, pgprot_t prot, bool write)
> +{
> + struct mm_struct *mm = vma->vm_mm;
> + pmd_t entry;
> + spinlock_t *ptl;
> +
> + ptl = pmd_lock(mm, pmd);
> + if (pmd_none(*pmd)) {
> + entry = pmd_mkhuge(pfn_pmd(pfn, prot));
> + if (write) {
> + entry = pmd_mkyoung(pmd_mkdirty(entry));
> + entry = maybe_pmd_mkwrite(entry, vma);
> + }
> + set_pmd_at(mm, addr, pmd, entry);
> + update_mmu_cache_pmd(vma, addr, pmd);
> + }
> + spin_unlock(ptl);
> + return VM_FAULT_NOPAGE;
> +}
What's the point of the return value?
Cheers,
Jeff
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^ permalink raw reply [flat|nested] 16+ messages in thread* Re: [PATCH 06/10] mm: Add vmf_insert_pfn_pmd()
2015-07-13 13:23 ` Jeff Moyer
@ 2015-07-13 15:02 ` Matthew Wilcox
0 siblings, 0 replies; 16+ messages in thread
From: Matthew Wilcox @ 2015-07-13 15:02 UTC (permalink / raw)
To: Jeff Moyer; +Cc: Matthew Wilcox, linux-fsdevel, linux-kernel, linux-mm
On Mon, Jul 13, 2015 at 09:23:41AM -0400, Jeff Moyer wrote:
> Matthew Wilcox <matthew.r.wilcox@intel.com> writes:
>
> > +static int insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr,
> > + pmd_t *pmd, unsigned long pfn, pgprot_t prot, bool write)
> > +{
> > + return VM_FAULT_NOPAGE;
> > +}
>
> What's the point of the return value?
Good point. Originally, it paralleled insert_pfn() in mm/memory.c, but it
became apparent that the return code of 0 or -Exxx was useless, and in converting insert_pfn_pmd over to VM_FAULT_ codes, all possible return codes were
going to be VM_FAULT_NOPAGE. It didn't occur to me to take it one step further and make the function return void.
It doesn't make much difference either way:
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 26d0fc1..5ffdcaa 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -837,7 +837,7 @@ int do_huge_pmd_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma,
return 0;
}
-static int insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr,
+static void insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr,
pmd_t *pmd, unsigned long pfn, pgprot_t prot, bool write)
{
struct mm_struct *mm = vma->vm_mm;
@@ -855,7 +855,6 @@ static int insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr,
update_mmu_cache_pmd(vma, addr, pmd);
}
spin_unlock(ptl);
- return VM_FAULT_NOPAGE;
}
int vmf_insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr,
@@ -877,7 +876,8 @@ int vmf_insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr,
return VM_FAULT_SIGBUS;
if (track_pfn_insert(vma, &pgprot, pfn))
return VM_FAULT_SIGBUS;
- return insert_pfn_pmd(vma, addr, pmd, pfn, pgprot, write);
+ insert_pfn_pmd(vma, addr, pmd, pfn, pgprot, write);
+ return VM_FAULT_NOPAGE;
}
int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm,
I suppose it's slightly cleaner. I'll integrate this for the next release.
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^ permalink raw reply related [flat|nested] 16+ messages in thread
* [PATCH 07/10] dax: Add huge page fault support
2015-07-10 20:29 [PATCH 00/10] Huge page support for DAX files Matthew Wilcox
` (5 preceding siblings ...)
2015-07-10 20:29 ` [PATCH 06/10] mm: Add vmf_insert_pfn_pmd() Matthew Wilcox
@ 2015-07-10 20:29 ` Matthew Wilcox
2015-07-13 15:05 ` Jan Kara
2015-07-10 20:29 ` [PATCH 08/10] ext2: Huge " Matthew Wilcox
` (2 subsequent siblings)
9 siblings, 1 reply; 16+ messages in thread
From: Matthew Wilcox @ 2015-07-10 20:29 UTC (permalink / raw)
To: linux-fsdevel, linux-kernel, linux-mm; +Cc: Matthew Wilcox
From: Matthew Wilcox <willy@linux.intel.com>
This is the support code for DAX-enabled filesystems to allow them to
provide huge pages in response to faults.
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
---
Documentation/filesystems/dax.txt | 7 +-
fs/dax.c | 152 ++++++++++++++++++++++++++++++++++++++
include/linux/dax.h | 14 ++++
3 files changed, 170 insertions(+), 3 deletions(-)
diff --git a/Documentation/filesystems/dax.txt b/Documentation/filesystems/dax.txt
index 7af2851..7bde640 100644
--- a/Documentation/filesystems/dax.txt
+++ b/Documentation/filesystems/dax.txt
@@ -60,9 +60,10 @@ Filesystem support consists of
- implementing the direct_IO address space operation, and calling
dax_do_io() instead of blockdev_direct_IO() if S_DAX is set
- implementing an mmap file operation for DAX files which sets the
- VM_MIXEDMAP flag on the VMA, and setting the vm_ops to include handlers
- for fault and page_mkwrite (which should probably call dax_fault() and
- dax_mkwrite(), passing the appropriate get_block() callback)
+ VM_MIXEDMAP and VM_HUGEPAGE flags on the VMA, and setting the vm_ops to
+ include handlers for fault, pmd_fault and page_mkwrite (which should
+ probably call dax_fault(), dax_pmd_fault() and dax_mkwrite(), passing the
+ appropriate get_block() callback)
- calling dax_truncate_page() instead of block_truncate_page() for DAX files
- calling dax_zero_page_range() instead of zero_user() for DAX files
- ensuring that there is sufficient locking between reads, writes,
diff --git a/fs/dax.c b/fs/dax.c
index c3e21cc..20cf3b0 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -484,6 +484,158 @@ int dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf,
}
EXPORT_SYMBOL_GPL(dax_fault);
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+/*
+ * The 'colour' (ie low bits) within a PMD of a page offset. This comes up
+ * more often than one might expect in the below function.
+ */
+#define PG_PMD_COLOUR ((PMD_SIZE >> PAGE_SHIFT) - 1)
+
+int __dax_pmd_fault(struct vm_area_struct *vma, unsigned long address,
+ pmd_t *pmd, unsigned int flags, get_block_t get_block,
+ dax_iodone_t complete_unwritten)
+{
+ struct file *file = vma->vm_file;
+ struct address_space *mapping = file->f_mapping;
+ struct inode *inode = mapping->host;
+ struct buffer_head bh;
+ unsigned blkbits = inode->i_blkbits;
+ unsigned long pmd_addr = address & PMD_MASK;
+ bool write = flags & FAULT_FLAG_WRITE;
+ long length;
+ void *kaddr;
+ pgoff_t size, pgoff;
+ sector_t block, sector;
+ unsigned long pfn;
+ int result = 0;
+
+ /* Fall back to PTEs if we're going to COW */
+ if (write && !(vma->vm_flags & VM_SHARED))
+ return VM_FAULT_FALLBACK;
+ /* If the PMD would extend outside the VMA */
+ if (pmd_addr < vma->vm_start)
+ return VM_FAULT_FALLBACK;
+ if ((pmd_addr + PMD_SIZE) > vma->vm_end)
+ return VM_FAULT_FALLBACK;
+
+ pgoff = ((pmd_addr - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff;
+ size = (i_size_read(inode) + PAGE_SIZE - 1) >> PAGE_SHIFT;
+ if (pgoff >= size)
+ return VM_FAULT_SIGBUS;
+ /* If the PMD would cover blocks out of the file */
+ if ((pgoff | PG_PMD_COLOUR) >= size)
+ return VM_FAULT_FALLBACK;
+
+ memset(&bh, 0, sizeof(bh));
+ block = (sector_t)pgoff << (PAGE_SHIFT - blkbits);
+
+ bh.b_size = PMD_SIZE;
+ length = get_block(inode, block, &bh, write);
+ if (length)
+ return VM_FAULT_SIGBUS;
+ i_mmap_lock_read(mapping);
+
+ /*
+ * If the filesystem isn't willing to tell us the length of a hole,
+ * just fall back to PTEs. Calling get_block 512 times in a loop
+ * would be silly.
+ */
+ if (!buffer_size_valid(&bh) || bh.b_size < PMD_SIZE)
+ goto fallback;
+
+ /* Guard against a race with truncate */
+ size = (i_size_read(inode) + PAGE_SIZE - 1) >> PAGE_SHIFT;
+ if (pgoff >= size) {
+ result = VM_FAULT_SIGBUS;
+ goto out;
+ }
+ if ((pgoff | PG_PMD_COLOUR) >= size)
+ goto fallback;
+
+ if (is_huge_zero_pmd(*pmd))
+ unmap_mapping_range(mapping, pgoff << PAGE_SHIFT, PMD_SIZE, 0);
+
+ if (!write && !buffer_mapped(&bh) && buffer_uptodate(&bh)) {
+ bool set;
+ spinlock_t *ptl;
+ struct mm_struct *mm = vma->vm_mm;
+ struct page *zero_page = get_huge_zero_page();
+ if (unlikely(!zero_page))
+ goto fallback;
+
+ ptl = pmd_lock(mm, pmd);
+ set = set_huge_zero_page(NULL, mm, vma, pmd_addr, pmd,
+ zero_page);
+ spin_unlock(ptl);
+ result = VM_FAULT_NOPAGE;
+ } else {
+ sector = bh.b_blocknr << (blkbits - 9);
+ length = bdev_direct_access(bh.b_bdev, sector, &kaddr, &pfn,
+ bh.b_size);
+ if (length < 0) {
+ result = VM_FAULT_SIGBUS;
+ goto out;
+ }
+ if ((length < PMD_SIZE) || (pfn & PG_PMD_COLOUR))
+ goto fallback;
+
+ if (buffer_unwritten(&bh) || buffer_new(&bh)) {
+ int i;
+ for (i = 0; i < PTRS_PER_PMD; i++)
+ clear_page(kaddr + i * PAGE_SIZE);
+ count_vm_event(PGMAJFAULT);
+ mem_cgroup_count_vm_event(vma->vm_mm, PGMAJFAULT);
+ result |= VM_FAULT_MAJOR;
+ }
+
+ result |= vmf_insert_pfn_pmd(vma, address, pmd, pfn, write);
+ }
+
+ out:
+ i_mmap_unlock_read(mapping);
+
+ if (buffer_unwritten(&bh))
+ complete_unwritten(&bh, !(result & VM_FAULT_ERROR));
+
+ return result;
+
+ fallback:
+ count_vm_event(THP_FAULT_FALLBACK);
+ result = VM_FAULT_FALLBACK;
+ goto out;
+}
+EXPORT_SYMBOL_GPL(__dax_pmd_fault);
+
+/**
+ * dax_pmd_fault - handle a PMD fault on a DAX file
+ * @vma: The virtual memory area where the fault occurred
+ * @vmf: The description of the fault
+ * @get_block: The filesystem method used to translate file offsets to blocks
+ *
+ * When a page fault occurs, filesystems may call this helper in their
+ * pmd_fault handler for DAX files.
+ */
+int dax_pmd_fault(struct vm_area_struct *vma, unsigned long address,
+ pmd_t *pmd, unsigned int flags, get_block_t get_block,
+ dax_iodone_t complete_unwritten)
+{
+ int result;
+ struct super_block *sb = file_inode(vma->vm_file)->i_sb;
+
+ if (flags & FAULT_FLAG_WRITE) {
+ sb_start_pagefault(sb);
+ file_update_time(vma->vm_file);
+ }
+ result = __dax_pmd_fault(vma, address, pmd, flags, get_block,
+ complete_unwritten);
+ if (flags & FAULT_FLAG_WRITE)
+ sb_end_pagefault(sb);
+
+ return result;
+}
+EXPORT_SYMBOL_GPL(dax_pmd_fault);
+#endif /* CONFIG_TRANSPARENT_HUGEPAGES */
+
/**
* dax_pfn_mkwrite - handle first write to DAX page
* @vma: The virtual memory area where the fault occurred
diff --git a/include/linux/dax.h b/include/linux/dax.h
index 9b51f9d..b415e52 100644
--- a/include/linux/dax.h
+++ b/include/linux/dax.h
@@ -14,6 +14,20 @@ int dax_fault(struct vm_area_struct *, struct vm_fault *, get_block_t,
dax_iodone_t);
int __dax_fault(struct vm_area_struct *, struct vm_fault *, get_block_t,
dax_iodone_t);
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+int dax_pmd_fault(struct vm_area_struct *, unsigned long addr, pmd_t *,
+ unsigned int flags, get_block_t, dax_iodone_t);
+int __dax_pmd_fault(struct vm_area_struct *, unsigned long addr, pmd_t *,
+ unsigned int flags, get_block_t, dax_iodone_t);
+#else
+static inline int dax_pmd_fault(struct vm_area_struct *vma, unsigned long addr,
+ pmd_t *pmd, unsigned int flags, get_block_t gb,
+ dax_iodone_t di)
+{
+ return VM_FAULT_FALLBACK;
+}
+#define __dax_pmd_fault dax_pmd_fault
+#endif
int dax_pfn_mkwrite(struct vm_area_struct *, struct vm_fault *);
#define dax_mkwrite(vma, vmf, gb, iod) dax_fault(vma, vmf, gb, iod)
#define __dax_mkwrite(vma, vmf, gb, iod) __dax_fault(vma, vmf, gb, iod)
--
2.1.4
--
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^ permalink raw reply related [flat|nested] 16+ messages in thread* Re: [PATCH 07/10] dax: Add huge page fault support
2015-07-10 20:29 ` [PATCH 07/10] dax: Add huge page fault support Matthew Wilcox
@ 2015-07-13 15:05 ` Jan Kara
2015-07-13 15:33 ` Matthew Wilcox
0 siblings, 1 reply; 16+ messages in thread
From: Jan Kara @ 2015-07-13 15:05 UTC (permalink / raw)
To: Matthew Wilcox; +Cc: linux-fsdevel, linux-kernel, linux-mm, Matthew Wilcox
On Fri 10-07-15 16:29:22, Matthew Wilcox wrote:
> From: Matthew Wilcox <willy@linux.intel.com>
>
> This is the support code for DAX-enabled filesystems to allow them to
> provide huge pages in response to faults.
>
> Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
...
> +int __dax_pmd_fault(struct vm_area_struct *vma, unsigned long address,
> + pmd_t *pmd, unsigned int flags, get_block_t get_block,
> + dax_iodone_t complete_unwritten)
> +{
> + struct file *file = vma->vm_file;
> + struct address_space *mapping = file->f_mapping;
> + struct inode *inode = mapping->host;
> + struct buffer_head bh;
> + unsigned blkbits = inode->i_blkbits;
> + unsigned long pmd_addr = address & PMD_MASK;
> + bool write = flags & FAULT_FLAG_WRITE;
> + long length;
> + void *kaddr;
> + pgoff_t size, pgoff;
> + sector_t block, sector;
> + unsigned long pfn;
> + int result = 0;
> +
> + /* Fall back to PTEs if we're going to COW */
> + if (write && !(vma->vm_flags & VM_SHARED))
> + return VM_FAULT_FALLBACK;
> + /* If the PMD would extend outside the VMA */
> + if (pmd_addr < vma->vm_start)
> + return VM_FAULT_FALLBACK;
> + if ((pmd_addr + PMD_SIZE) > vma->vm_end)
> + return VM_FAULT_FALLBACK;
> +
> + pgoff = ((pmd_addr - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff;
> + size = (i_size_read(inode) + PAGE_SIZE - 1) >> PAGE_SHIFT;
> + if (pgoff >= size)
> + return VM_FAULT_SIGBUS;
> + /* If the PMD would cover blocks out of the file */
> + if ((pgoff | PG_PMD_COLOUR) >= size)
> + return VM_FAULT_FALLBACK;
> +
> + memset(&bh, 0, sizeof(bh));
> + block = (sector_t)pgoff << (PAGE_SHIFT - blkbits);
> +
> + bh.b_size = PMD_SIZE;
> + length = get_block(inode, block, &bh, write);
> + if (length)
> + return VM_FAULT_SIGBUS;
> + i_mmap_lock_read(mapping);
> +
> + /*
> + * If the filesystem isn't willing to tell us the length of a hole,
> + * just fall back to PTEs. Calling get_block 512 times in a loop
> + * would be silly.
> + */
> + if (!buffer_size_valid(&bh) || bh.b_size < PMD_SIZE)
> + goto fallback;
> +
> + /* Guard against a race with truncate */
> + size = (i_size_read(inode) + PAGE_SIZE - 1) >> PAGE_SHIFT;
> + if (pgoff >= size) {
> + result = VM_FAULT_SIGBUS;
> + goto out;
> + }
So if this is a writeable fault and we race with truncate, we can leave
stale blocks beyond i_size, can't we? Ah, looking at dax_insert_mapping()
this seems to be a documented quirk of DAX mmap code. Would be worth
mentioning here as well so that people don't wonder...
Otherwise the patch looks good to me.
Honza
> + if ((pgoff | PG_PMD_COLOUR) >= size)
> + goto fallback;
> +
> + if (is_huge_zero_pmd(*pmd))
> + unmap_mapping_range(mapping, pgoff << PAGE_SHIFT, PMD_SIZE, 0);
> +
> + if (!write && !buffer_mapped(&bh) && buffer_uptodate(&bh)) {
> + bool set;
> + spinlock_t *ptl;
> + struct mm_struct *mm = vma->vm_mm;
> + struct page *zero_page = get_huge_zero_page();
> + if (unlikely(!zero_page))
> + goto fallback;
> +
> + ptl = pmd_lock(mm, pmd);
> + set = set_huge_zero_page(NULL, mm, vma, pmd_addr, pmd,
> + zero_page);
> + spin_unlock(ptl);
> + result = VM_FAULT_NOPAGE;
> + } else {
> + sector = bh.b_blocknr << (blkbits - 9);
> + length = bdev_direct_access(bh.b_bdev, sector, &kaddr, &pfn,
> + bh.b_size);
> + if (length < 0) {
> + result = VM_FAULT_SIGBUS;
> + goto out;
> + }
> + if ((length < PMD_SIZE) || (pfn & PG_PMD_COLOUR))
> + goto fallback;
> +
> + if (buffer_unwritten(&bh) || buffer_new(&bh)) {
> + int i;
> + for (i = 0; i < PTRS_PER_PMD; i++)
> + clear_page(kaddr + i * PAGE_SIZE);
> + count_vm_event(PGMAJFAULT);
> + mem_cgroup_count_vm_event(vma->vm_mm, PGMAJFAULT);
> + result |= VM_FAULT_MAJOR;
> + }
> +
> + result |= vmf_insert_pfn_pmd(vma, address, pmd, pfn, write);
> + }
> +
> + out:
> + i_mmap_unlock_read(mapping);
> +
> + if (buffer_unwritten(&bh))
> + complete_unwritten(&bh, !(result & VM_FAULT_ERROR));
> +
> + return result;
> +
> + fallback:
> + count_vm_event(THP_FAULT_FALLBACK);
> + result = VM_FAULT_FALLBACK;
> + goto out;
> +}
> +EXPORT_SYMBOL_GPL(__dax_pmd_fault);
> +
> +/**
> + * dax_pmd_fault - handle a PMD fault on a DAX file
> + * @vma: The virtual memory area where the fault occurred
> + * @vmf: The description of the fault
> + * @get_block: The filesystem method used to translate file offsets to blocks
> + *
> + * When a page fault occurs, filesystems may call this helper in their
> + * pmd_fault handler for DAX files.
> + */
> +int dax_pmd_fault(struct vm_area_struct *vma, unsigned long address,
> + pmd_t *pmd, unsigned int flags, get_block_t get_block,
> + dax_iodone_t complete_unwritten)
> +{
> + int result;
> + struct super_block *sb = file_inode(vma->vm_file)->i_sb;
> +
> + if (flags & FAULT_FLAG_WRITE) {
> + sb_start_pagefault(sb);
> + file_update_time(vma->vm_file);
> + }
> + result = __dax_pmd_fault(vma, address, pmd, flags, get_block,
> + complete_unwritten);
> + if (flags & FAULT_FLAG_WRITE)
> + sb_end_pagefault(sb);
> +
> + return result;
> +}
> +EXPORT_SYMBOL_GPL(dax_pmd_fault);
> +#endif /* CONFIG_TRANSPARENT_HUGEPAGES */
> +
> /**
> * dax_pfn_mkwrite - handle first write to DAX page
> * @vma: The virtual memory area where the fault occurred
> diff --git a/include/linux/dax.h b/include/linux/dax.h
> index 9b51f9d..b415e52 100644
> --- a/include/linux/dax.h
> +++ b/include/linux/dax.h
> @@ -14,6 +14,20 @@ int dax_fault(struct vm_area_struct *, struct vm_fault *, get_block_t,
> dax_iodone_t);
> int __dax_fault(struct vm_area_struct *, struct vm_fault *, get_block_t,
> dax_iodone_t);
> +#ifdef CONFIG_TRANSPARENT_HUGEPAGE
> +int dax_pmd_fault(struct vm_area_struct *, unsigned long addr, pmd_t *,
> + unsigned int flags, get_block_t, dax_iodone_t);
> +int __dax_pmd_fault(struct vm_area_struct *, unsigned long addr, pmd_t *,
> + unsigned int flags, get_block_t, dax_iodone_t);
> +#else
> +static inline int dax_pmd_fault(struct vm_area_struct *vma, unsigned long addr,
> + pmd_t *pmd, unsigned int flags, get_block_t gb,
> + dax_iodone_t di)
> +{
> + return VM_FAULT_FALLBACK;
> +}
> +#define __dax_pmd_fault dax_pmd_fault
> +#endif
> int dax_pfn_mkwrite(struct vm_area_struct *, struct vm_fault *);
> #define dax_mkwrite(vma, vmf, gb, iod) dax_fault(vma, vmf, gb, iod)
> #define __dax_mkwrite(vma, vmf, gb, iod) __dax_fault(vma, vmf, gb, iod)
> --
> 2.1.4
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
--
Jan Kara <jack@suse.cz>
SUSE Labs, CR
^ permalink raw reply [flat|nested] 16+ messages in thread* Re: [PATCH 07/10] dax: Add huge page fault support
2015-07-13 15:05 ` Jan Kara
@ 2015-07-13 15:33 ` Matthew Wilcox
0 siblings, 0 replies; 16+ messages in thread
From: Matthew Wilcox @ 2015-07-13 15:33 UTC (permalink / raw)
To: Jan Kara; +Cc: Matthew Wilcox, linux-fsdevel, linux-kernel, linux-mm
On Mon, Jul 13, 2015 at 05:05:00PM +0200, Jan Kara wrote:
> So if this is a writeable fault and we race with truncate, we can leave
> stale blocks beyond i_size, can't we? Ah, looking at dax_insert_mapping()
> this seems to be a documented quirk of DAX mmap code. Would be worth
> mentioning here as well so that people don't wonder...
Thanks!
- /* Guard against a race with truncate */
+ /*
+ * If a truncate happened while we were allocating blocks, we may
+ * leave blocks allocated to the file that are beyond EOF. We can't
+ * take i_mutex here, so just leave them hanging; they'll be freed
+ * when the file is deleted.
+ */
is what I'll commit.
^ permalink raw reply [flat|nested] 16+ messages in thread
* [PATCH 08/10] ext2: Huge page fault support
2015-07-10 20:29 [PATCH 00/10] Huge page support for DAX files Matthew Wilcox
` (6 preceding siblings ...)
2015-07-10 20:29 ` [PATCH 07/10] dax: Add huge page fault support Matthew Wilcox
@ 2015-07-10 20:29 ` Matthew Wilcox
2015-07-10 20:29 ` [PATCH 09/10] ext4: " Matthew Wilcox
2015-07-10 20:29 ` [PATCH 10/10] xfs: " Matthew Wilcox
9 siblings, 0 replies; 16+ messages in thread
From: Matthew Wilcox @ 2015-07-10 20:29 UTC (permalink / raw)
To: linux-fsdevel, linux-kernel, linux-mm; +Cc: Matthew Wilcox
From: Matthew Wilcox <willy@linux.intel.com>
Use DAX to provide support for huge pages.
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
---
fs/ext2/file.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/fs/ext2/file.c b/fs/ext2/file.c
index db4c299..1982c3f 100644
--- a/fs/ext2/file.c
+++ b/fs/ext2/file.c
@@ -32,6 +32,12 @@ static int ext2_dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
return dax_fault(vma, vmf, ext2_get_block, NULL);
}
+static int ext2_dax_pmd_fault(struct vm_area_struct *vma, unsigned long addr,
+ pmd_t *pmd, unsigned int flags)
+{
+ return dax_pmd_fault(vma, addr, pmd, flags, ext2_get_block, NULL);
+}
+
static int ext2_dax_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
{
return dax_mkwrite(vma, vmf, ext2_get_block, NULL);
@@ -39,6 +45,7 @@ static int ext2_dax_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
static const struct vm_operations_struct ext2_dax_vm_ops = {
.fault = ext2_dax_fault,
+ .pmd_fault = ext2_dax_pmd_fault,
.page_mkwrite = ext2_dax_mkwrite,
.pfn_mkwrite = dax_pfn_mkwrite,
};
@@ -50,7 +57,7 @@ static int ext2_file_mmap(struct file *file, struct vm_area_struct *vma)
file_accessed(file);
vma->vm_ops = &ext2_dax_vm_ops;
- vma->vm_flags |= VM_MIXEDMAP;
+ vma->vm_flags |= VM_MIXEDMAP | VM_HUGEPAGE;
return 0;
}
#else
--
2.1.4
--
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^ permalink raw reply related [flat|nested] 16+ messages in thread* [PATCH 09/10] ext4: Huge page fault support
2015-07-10 20:29 [PATCH 00/10] Huge page support for DAX files Matthew Wilcox
` (7 preceding siblings ...)
2015-07-10 20:29 ` [PATCH 08/10] ext2: Huge " Matthew Wilcox
@ 2015-07-10 20:29 ` Matthew Wilcox
2015-07-10 20:29 ` [PATCH 10/10] xfs: " Matthew Wilcox
9 siblings, 0 replies; 16+ messages in thread
From: Matthew Wilcox @ 2015-07-10 20:29 UTC (permalink / raw)
To: linux-fsdevel, linux-kernel, linux-mm; +Cc: Matthew Wilcox
From: Matthew Wilcox <willy@linux.intel.com>
Use DAX to provide support for huge pages.
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
---
fs/ext4/file.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/fs/ext4/file.c b/fs/ext4/file.c
index 34d814f..ca5302a 100644
--- a/fs/ext4/file.c
+++ b/fs/ext4/file.c
@@ -210,6 +210,13 @@ static int ext4_dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
return dax_fault(vma, vmf, ext4_get_block_write, ext4_end_io_unwritten);
}
+static int ext4_dax_pmd_fault(struct vm_area_struct *vma, unsigned long addr,
+ pmd_t *pmd, unsigned int flags)
+{
+ return dax_pmd_fault(vma, addr, pmd, flags, ext4_get_block_write,
+ ext4_end_io_unwritten);
+}
+
static int ext4_dax_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
{
return dax_mkwrite(vma, vmf, ext4_get_block_write,
@@ -218,6 +225,7 @@ static int ext4_dax_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
static const struct vm_operations_struct ext4_dax_vm_ops = {
.fault = ext4_dax_fault,
+ .pmd_fault = ext4_dax_pmd_fault,
.page_mkwrite = ext4_dax_mkwrite,
.pfn_mkwrite = dax_pfn_mkwrite,
};
@@ -245,7 +253,7 @@ static int ext4_file_mmap(struct file *file, struct vm_area_struct *vma)
file_accessed(file);
if (IS_DAX(file_inode(file))) {
vma->vm_ops = &ext4_dax_vm_ops;
- vma->vm_flags |= VM_MIXEDMAP;
+ vma->vm_flags |= VM_MIXEDMAP | VM_HUGEPAGE;
} else {
vma->vm_ops = &ext4_file_vm_ops;
}
--
2.1.4
--
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the body to majordomo@kvack.org. For more info on Linux MM,
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^ permalink raw reply related [flat|nested] 16+ messages in thread* [PATCH 10/10] xfs: Huge page fault support
2015-07-10 20:29 [PATCH 00/10] Huge page support for DAX files Matthew Wilcox
` (8 preceding siblings ...)
2015-07-10 20:29 ` [PATCH 09/10] ext4: " Matthew Wilcox
@ 2015-07-10 20:29 ` Matthew Wilcox
9 siblings, 0 replies; 16+ messages in thread
From: Matthew Wilcox @ 2015-07-10 20:29 UTC (permalink / raw)
To: linux-fsdevel, linux-kernel, linux-mm; +Cc: Matthew Wilcox
From: Matthew Wilcox <willy@linux.intel.com>
Use DAX to provide support for huge pages.
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
---
fs/xfs/xfs_file.c | 30 +++++++++++++++++++++++++++++-
fs/xfs/xfs_trace.h | 1 +
2 files changed, 30 insertions(+), 1 deletion(-)
diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index a212b7b..d3ea50c 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -1534,8 +1534,36 @@ xfs_filemap_fault(
return ret;
}
+STATIC int
+xfs_filemap_pmd_fault(
+ struct vm_area_struct *vma,
+ unsigned long addr,
+ pmd_t *pmd,
+ unsigned int flags)
+{
+ struct inode *inode = file_inode(vma->vm_file);
+ struct xfs_inode *ip = XFS_I(inode);
+ int ret;
+
+ if (!IS_DAX(inode))
+ return VM_FAULT_FALLBACK;
+
+ trace_xfs_filemap_pmd_fault(ip);
+
+ sb_start_pagefault(inode->i_sb);
+ file_update_time(vma->vm_file);
+ xfs_ilock(XFS_I(inode), XFS_MMAPLOCK_SHARED);
+ ret = __dax_pmd_fault(vma, addr, pmd, flags, xfs_get_blocks_direct,
+ xfs_end_io_dax_write);
+ xfs_iunlock(XFS_I(inode), XFS_MMAPLOCK_SHARED);
+ sb_end_pagefault(inode->i_sb);
+
+ return ret;
+}
+
static const struct vm_operations_struct xfs_file_vm_ops = {
.fault = xfs_filemap_fault,
+ .pmd_fault = xfs_filemap_pmd_fault,
.map_pages = filemap_map_pages,
.page_mkwrite = xfs_filemap_page_mkwrite,
};
@@ -1548,7 +1576,7 @@ xfs_file_mmap(
file_accessed(filp);
vma->vm_ops = &xfs_file_vm_ops;
if (IS_DAX(file_inode(filp)))
- vma->vm_flags |= VM_MIXEDMAP;
+ vma->vm_flags |= VM_MIXEDMAP | VM_HUGEPAGE;
return 0;
}
diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h
index 8d916d3..8229cae 100644
--- a/fs/xfs/xfs_trace.h
+++ b/fs/xfs/xfs_trace.h
@@ -687,6 +687,7 @@ DEFINE_INODE_EVENT(xfs_inode_clear_eofblocks_tag);
DEFINE_INODE_EVENT(xfs_inode_free_eofblocks_invalid);
DEFINE_INODE_EVENT(xfs_filemap_fault);
+DEFINE_INODE_EVENT(xfs_filemap_pmd_fault);
DEFINE_INODE_EVENT(xfs_filemap_page_mkwrite);
DECLARE_EVENT_CLASS(xfs_iref_class,
--
2.1.4
--
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^ permalink raw reply related [flat|nested] 16+ messages in thread