Re: [PATCH v3 4/5] dax: add tracepoints to dax_pmd_load_hole()

[Steven Rostedt]

On Thu,  1 Dec 2016 09:37:50 -0700
Ross Zwisler  wrote:

> Add tracepoints to dax_pmd_load_hole(), following the same logging
> conventions as the tracepoints in dax_iomap_pmd_fault().
> 
> Here is an example PMD fault showing the new tracepoints:
> 
> read_big-1478  [004]    238.242188: xfs_filemap_pmd_fault: dev 259:0
> ino 0x1003
> 
> read_big-1478  [004]    238.242191: dax_pmd_fault: dev 259:0 ino 0x1003
> shared ALLOW_RETRY|KILLABLE|USER address 0x1040 vm_start 0x1020
> vm_end 0x1060 pgoff 0x200 max_pgoff 0x1400
> 
> read_big-1478  [004]    238.242390: dax_pmd_load_hole: dev 259:0 ino
> 0x1003 shared address 0x1040 zero_page ea0002c2 radix_entry
> 0x1e
> 
> read_big-1478  [004]    238.242392: dax_pmd_fault_done: dev 259:0 ino
> 0x1003 shared ALLOW_RETRY|KILLABLE|USER address 0x1040 vm_start
> 0x1020 vm_end 0x1060 pgoff 0x200 max_pgoff 0x1400 NOPAGE
> 
> Signed-off-by: Ross Zwisler 
> Reviewed-by: Jan Kara 
> ---

Acked-by: Steven Rostedt 

-- Steve

Re: [PATCH v3 4/5] dax: add tracepoints to dax_pmd_load_hole()

[Steven Rostedt]

On Thu,  1 Dec 2016 09:37:50 -0700
Ross Zwisler  wrote:

> Add tracepoints to dax_pmd_load_hole(), following the same logging
> conventions as the tracepoints in dax_iomap_pmd_fault().
> 
> Here is an example PMD fault showing the new tracepoints:
> 
> read_big-1478  [004]    238.242188: xfs_filemap_pmd_fault: dev 259:0
> ino 0x1003
> 
> read_big-1478  [004]    238.242191: dax_pmd_fault: dev 259:0 ino 0x1003
> shared ALLOW_RETRY|KILLABLE|USER address 0x1040 vm_start 0x1020
> vm_end 0x1060 pgoff 0x200 max_pgoff 0x1400
> 
> read_big-1478  [004]    238.242390: dax_pmd_load_hole: dev 259:0 ino
> 0x1003 shared address 0x1040 zero_page ea0002c2 radix_entry
> 0x1e
> 
> read_big-1478  [004]    238.242392: dax_pmd_fault_done: dev 259:0 ino
> 0x1003 shared ALLOW_RETRY|KILLABLE|USER address 0x1040 vm_start
> 0x1020 vm_end 0x1060 pgoff 0x200 max_pgoff 0x1400 NOPAGE
> 
> Signed-off-by: Ross Zwisler 
> Reviewed-by: Jan Kara 
> ---

Acked-by: Steven Rostedt 

-- Steve

[PATCH v3 4/5] dax: add tracepoints to dax_pmd_load_hole()

[Ross Zwisler]

Add tracepoints to dax_pmd_load_hole(), following the same logging
conventions as the tracepoints in dax_iomap_pmd_fault().

Here is an example PMD fault showing the new tracepoints:

read_big-1478  [004]    238.242188: xfs_filemap_pmd_fault: dev 259:0
ino 0x1003

read_big-1478  [004]    238.242191: dax_pmd_fault: dev 259:0 ino 0x1003
shared ALLOW_RETRY|KILLABLE|USER address 0x1040 vm_start 0x1020
vm_end 0x1060 pgoff 0x200 max_pgoff 0x1400

read_big-1478  [004]    238.242390: dax_pmd_load_hole: dev 259:0 ino
0x1003 shared address 0x1040 zero_page ea0002c2 radix_entry
0x1e

read_big-1478  [004]    238.242392: dax_pmd_fault_done: dev 259:0 ino
0x1003 shared ALLOW_RETRY|KILLABLE|USER address 0x1040 vm_start
0x1020 vm_end 0x1060 pgoff 0x200 max_pgoff 0x1400 NOPAGE

Signed-off-by: Ross Zwisler 
Reviewed-by: Jan Kara 
---
 fs/dax.c  | 14 ++
 include/trace/events/fs_dax.h | 42 ++
 2 files changed, 52 insertions(+), 4 deletions(-)

diff --git a/fs/dax.c b/fs/dax.c
index 360995a..61b3080 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -1269,33 +1269,39 @@ static int dax_pmd_load_hole(struct vm_area_struct 
*vma, pmd_t *pmd,
 {
struct address_space *mapping = vma->vm_file->f_mapping;
unsigned long pmd_addr = address & PMD_MASK;
+   struct inode *inode = mapping->host;
struct page *zero_page;
+   void *ret = NULL;
spinlock_t *ptl;
pmd_t pmd_entry;
-   void *ret;
 
zero_page = mm_get_huge_zero_page(vma->vm_mm);
 
if (unlikely(!zero_page))
-   return VM_FAULT_FALLBACK;
+   goto fallback;
 
ret = dax_insert_mapping_entry(mapping, vmf, *entryp, 0,
RADIX_DAX_PMD | RADIX_DAX_HZP);
if (IS_ERR(ret))
-   return VM_FAULT_FALLBACK;
+   goto fallback;
*entryp = ret;
 
ptl = pmd_lock(vma->vm_mm, pmd);
if (!pmd_none(*pmd)) {
spin_unlock(ptl);
-   return VM_FAULT_FALLBACK;
+   goto fallback;
}
 
pmd_entry = mk_pmd(zero_page, vma->vm_page_prot);
pmd_entry = pmd_mkhuge(pmd_entry);
set_pmd_at(vma->vm_mm, pmd_addr, pmd, pmd_entry);
spin_unlock(ptl);
+   trace_dax_pmd_load_hole(inode, vma, address, zero_page, ret);
return VM_FAULT_NOPAGE;
+
+fallback:
+   trace_dax_pmd_load_hole_fallback(inode, vma, address, zero_page, ret);
+   return VM_FAULT_FALLBACK;
 }
 
 int dax_iomap_pmd_fault(struct vm_area_struct *vma, unsigned long address,
diff --git a/include/trace/events/fs_dax.h b/include/trace/events/fs_dax.h
index 58b0b56..43f1263 100644
--- a/include/trace/events/fs_dax.h
+++ b/include/trace/events/fs_dax.h
@@ -61,6 +61,48 @@ DEFINE_EVENT(dax_pmd_fault_class, name, \
 DEFINE_PMD_FAULT_EVENT(dax_pmd_fault);
 DEFINE_PMD_FAULT_EVENT(dax_pmd_fault_done);
 
+DECLARE_EVENT_CLASS(dax_pmd_load_hole_class,
+   TP_PROTO(struct inode *inode, struct vm_area_struct *vma,
+   unsigned long address, struct page *zero_page,
+   void *radix_entry),
+   TP_ARGS(inode, vma, address, zero_page, radix_entry),
+   TP_STRUCT__entry(
+   __field(unsigned long, ino)
+   __field(unsigned long, vm_flags)
+   __field(unsigned long, address)
+   __field(struct page *, zero_page)
+   __field(void *, radix_entry)
+   __field(dev_t, dev)
+   ),
+   TP_fast_assign(
+   __entry->dev = inode->i_sb->s_dev;
+   __entry->ino = inode->i_ino;
+   __entry->vm_flags = vma->vm_flags;
+   __entry->address = address;
+   __entry->zero_page = zero_page;
+   __entry->radix_entry = radix_entry;
+   ),
+   TP_printk("dev %d:%d ino %#lx %s address %#lx zero_page %p "
+   "radix_entry %#lx",
+   MAJOR(__entry->dev),
+   MINOR(__entry->dev),
+   __entry->ino,
+   __entry->vm_flags & VM_SHARED ? "shared" : "private",
+   __entry->address,
+   __entry->zero_page,
+   (unsigned long)__entry->radix_entry
+   )
+)
+
+#define DEFINE_PMD_LOAD_HOLE_EVENT(name) \
+DEFINE_EVENT(dax_pmd_load_hole_class, name, \
+   TP_PROTO(struct inode *inode, struct vm_area_struct *vma, \
+   unsigned long address, struct page *zero_page, \
+   void *radix_entry), \
+   TP_ARGS(inode, vma, address, zero_page, radix_entry))
+
+DEFINE_PMD_LOAD_HOLE_EVENT(dax_pmd_load_hole);
+DEFINE_PMD_LOAD_HOLE_EVENT(dax_pmd_load_hole_fallback);
 
 #endif /* _TRACE_FS_DAX_H */
 
-- 
2.7.4

[PATCH v3 4/5] dax: add tracepoints to dax_pmd_load_hole()

[Ross Zwisler]

Add tracepoints to dax_pmd_load_hole(), following the same logging
conventions as the tracepoints in dax_iomap_pmd_fault().

Here is an example PMD fault showing the new tracepoints:

read_big-1478  [004]    238.242188: xfs_filemap_pmd_fault: dev 259:0
ino 0x1003

read_big-1478  [004]    238.242191: dax_pmd_fault: dev 259:0 ino 0x1003
shared ALLOW_RETRY|KILLABLE|USER address 0x1040 vm_start 0x1020
vm_end 0x1060 pgoff 0x200 max_pgoff 0x1400

read_big-1478  [004]    238.242390: dax_pmd_load_hole: dev 259:0 ino
0x1003 shared address 0x1040 zero_page ea0002c2 radix_entry
0x1e

read_big-1478  [004]    238.242392: dax_pmd_fault_done: dev 259:0 ino
0x1003 shared ALLOW_RETRY|KILLABLE|USER address 0x1040 vm_start
0x1020 vm_end 0x1060 pgoff 0x200 max_pgoff 0x1400 NOPAGE

Signed-off-by: Ross Zwisler 
Reviewed-by: Jan Kara 
---
 fs/dax.c  | 14 ++
 include/trace/events/fs_dax.h | 42 ++
 2 files changed, 52 insertions(+), 4 deletions(-)

diff --git a/fs/dax.c b/fs/dax.c
index 360995a..61b3080 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -1269,33 +1269,39 @@ static int dax_pmd_load_hole(struct vm_area_struct 
*vma, pmd_t *pmd,
 {
struct address_space *mapping = vma->vm_file->f_mapping;
unsigned long pmd_addr = address & PMD_MASK;
+   struct inode *inode = mapping->host;
struct page *zero_page;
+   void *ret = NULL;
spinlock_t *ptl;
pmd_t pmd_entry;
-   void *ret;
 
zero_page = mm_get_huge_zero_page(vma->vm_mm);
 
if (unlikely(!zero_page))
-   return VM_FAULT_FALLBACK;
+   goto fallback;
 
ret = dax_insert_mapping_entry(mapping, vmf, *entryp, 0,
RADIX_DAX_PMD | RADIX_DAX_HZP);
if (IS_ERR(ret))
-   return VM_FAULT_FALLBACK;
+   goto fallback;
*entryp = ret;
 
ptl = pmd_lock(vma->vm_mm, pmd);
if (!pmd_none(*pmd)) {
spin_unlock(ptl);
-   return VM_FAULT_FALLBACK;
+   goto fallback;
}
 
pmd_entry = mk_pmd(zero_page, vma->vm_page_prot);
pmd_entry = pmd_mkhuge(pmd_entry);
set_pmd_at(vma->vm_mm, pmd_addr, pmd, pmd_entry);
spin_unlock(ptl);
+   trace_dax_pmd_load_hole(inode, vma, address, zero_page, ret);
return VM_FAULT_NOPAGE;
+
+fallback:
+   trace_dax_pmd_load_hole_fallback(inode, vma, address, zero_page, ret);
+   return VM_FAULT_FALLBACK;
 }
 
 int dax_iomap_pmd_fault(struct vm_area_struct *vma, unsigned long address,
diff --git a/include/trace/events/fs_dax.h b/include/trace/events/fs_dax.h
index 58b0b56..43f1263 100644
--- a/include/trace/events/fs_dax.h
+++ b/include/trace/events/fs_dax.h
@@ -61,6 +61,48 @@ DEFINE_EVENT(dax_pmd_fault_class, name, \
 DEFINE_PMD_FAULT_EVENT(dax_pmd_fault);
 DEFINE_PMD_FAULT_EVENT(dax_pmd_fault_done);
 
+DECLARE_EVENT_CLASS(dax_pmd_load_hole_class,
+   TP_PROTO(struct inode *inode, struct vm_area_struct *vma,
+   unsigned long address, struct page *zero_page,
+   void *radix_entry),
+   TP_ARGS(inode, vma, address, zero_page, radix_entry),
+   TP_STRUCT__entry(
+   __field(unsigned long, ino)
+   __field(unsigned long, vm_flags)
+   __field(unsigned long, address)
+   __field(struct page *, zero_page)
+   __field(void *, radix_entry)
+   __field(dev_t, dev)
+   ),
+   TP_fast_assign(
+   __entry->dev = inode->i_sb->s_dev;
+   __entry->ino = inode->i_ino;
+   __entry->vm_flags = vma->vm_flags;
+   __entry->address = address;
+   __entry->zero_page = zero_page;
+   __entry->radix_entry = radix_entry;
+   ),
+   TP_printk("dev %d:%d ino %#lx %s address %#lx zero_page %p "
+   "radix_entry %#lx",
+   MAJOR(__entry->dev),
+   MINOR(__entry->dev),
+   __entry->ino,
+   __entry->vm_flags & VM_SHARED ? "shared" : "private",
+   __entry->address,
+   __entry->zero_page,
+   (unsigned long)__entry->radix_entry
+   )
+)
+
+#define DEFINE_PMD_LOAD_HOLE_EVENT(name) \
+DEFINE_EVENT(dax_pmd_load_hole_class, name, \
+   TP_PROTO(struct inode *inode, struct vm_area_struct *vma, \
+   unsigned long address, struct page *zero_page, \
+   void *radix_entry), \
+   TP_ARGS(inode, vma, address, zero_page, radix_entry))
+
+DEFINE_PMD_LOAD_HOLE_EVENT(dax_pmd_load_hole);
+DEFINE_PMD_LOAD_HOLE_EVENT(dax_pmd_load_hole_fallback);
 
 #endif /* _TRACE_FS_DAX_H */
 
-- 
2.7.4