Add tracepoints to dax_pmd_insert_mapping(), following the same logging
conventions as the tracepoints in dax_iomap_pmd_fault().
Here is an example PMD fault showing the new tracepoints:
big-1544 [006] .... 48.153479: dax_pmd_fault: shared mapping write
address 0x10505000 vm_start 0x10200000 vm_end 0x10700000 pgoff 0x200
max_pgoff 0x1400
big-1544 [006] .... 48.155230: dax_pmd_insert_mapping: shared mapping
write address 0x10505000 length 0x200000 pfn 0x100600 DEV|MAP radix_entry
0xc000e
big-1544 [006] .... 48.155266: dax_pmd_fault_done: shared mapping write
address 0x10505000 vm_start 0x10200000 vm_end 0x10700000 pgoff 0x200
max_pgoff 0x1400 NOPAGE
Signed-off-by: Ross Zwisler <ross.zwisler@xxxxxxxxxxxxxxx>
---
fs/dax.c | 10 +++++++---
include/linux/pfn_t.h | 6 ++++++
include/trace/events/fs_dax.h | 42 ++++++++++++++++++++++++++++++++++++++++++
3 files changed, 55 insertions(+), 3 deletions(-)
diff --git a/fs/dax.c b/fs/dax.c
index 2824414..d6ba4a3 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -1236,10 +1236,10 @@ static int dax_pmd_insert_mapping(struct vm_area_struct *vma, pmd_t *pmd,
.size = PMD_SIZE,
};
long length = dax_map_atomic(bdev, &dax);
- void *ret;
+ void *ret = NULL;
if (length < 0) /* dax_map_atomic() failed */
- return VM_FAULT_FALLBACK;
+ goto fallback;
if (length < PMD_SIZE)
goto unmap_fallback;
if (pfn_t_to_pfn(dax.pfn) & PG_PMD_COLOUR)
@@ -1252,13 +1252,17 @@ static int dax_pmd_insert_mapping(struct vm_area_struct *vma, pmd_t *pmd,
ret = dax_insert_mapping_entry(mapping, vmf, *entryp, dax.sector,
RADIX_DAX_PMD);
if (IS_ERR(ret))
- return VM_FAULT_FALLBACK;
+ goto fallback;
*entryp = ret;
+ trace_dax_pmd_insert_mapping(vma, address, write, length, dax.pfn, ret);
return vmf_insert_pfn_pmd(vma, address, pmd, dax.pfn, write);
unmap_fallback:
dax_unmap_atomic(bdev, &dax);
+fallback:
+ trace_dax_pmd_insert_mapping_fallback(vma, address, write, length,
+ dax.pfn, ret);
return VM_FAULT_FALLBACK;
}
diff --git a/include/linux/pfn_t.h b/include/linux/pfn_t.h
index a3d90b9..033fc7b 100644
--- a/include/linux/pfn_t.h
+++ b/include/linux/pfn_t.h
@@ -15,6 +15,12 @@
#define PFN_DEV (1ULL << (BITS_PER_LONG_LONG - 3))
#define PFN_MAP (1ULL << (BITS_PER_LONG_LONG - 4))
+#define PFN_FLAGS_TRACE \
+ { PFN_SG_CHAIN, "SG_CHAIN" }, \
+ { PFN_SG_LAST, "SG_LAST" }, \
+ { PFN_DEV, "DEV" }, \
+ { PFN_MAP, "MAP" }
+
static inline pfn_t __pfn_to_pfn_t(unsigned long pfn, u64 flags)
{
pfn_t pfn_t = { .val = pfn | (flags & PFN_FLAGS_MASK), };
diff --git a/include/trace/events/fs_dax.h b/include/trace/events/fs_dax.h
index 8814b1a..a03f820 100644
--- a/include/trace/events/fs_dax.h
+++ b/include/trace/events/fs_dax.h
@@ -87,6 +87,48 @@ DEFINE_EVENT(dax_pmd_load_hole_class, name, \
DEFINE_PMD_LOAD_HOLE_EVENT(dax_pmd_load_hole);
DEFINE_PMD_LOAD_HOLE_EVENT(dax_pmd_load_hole_fallback);
+DECLARE_EVENT_CLASS(dax_pmd_insert_mapping_class,
+ TP_PROTO(struct vm_area_struct *vma, unsigned long address, int write,
+ long length, pfn_t pfn, void *radix_entry),
+ TP_ARGS(vma, address, write, length, pfn, radix_entry),
+ TP_STRUCT__entry(
+ __field(unsigned long, vm_flags)
+ __field(unsigned long, address)
+ __field(int, write)
+ __field(long, length)
+ __field(u64, pfn_val)
+ __field(void *, radix_entry)
+ ),
+ TP_fast_assign(
+ __entry->vm_flags = vma->vm_flags;
+ __entry->address = address;
+ __entry->write = write;
+ __entry->length = length;
+ __entry->pfn_val = pfn.val;
+ __entry->radix_entry = radix_entry;
+ ),
+ TP_printk("%s mapping %s address %#lx length %#lx pfn %#llx %s"
+ " radix_entry %#lx",
+ __entry->vm_flags & VM_SHARED ? "shared" : "private",
+ __entry->write ? "write" : "read",
+ __entry->address,
+ __entry->length,
+ __entry->pfn_val & ~PFN_FLAGS_MASK,
+ __print_flags(__entry->pfn_val & PFN_FLAGS_MASK, "|",
+ PFN_FLAGS_TRACE),
+ (unsigned long)__entry->radix_entry
+ )
+)
+
+#define DEFINE_PMD_INSERT_MAPPING_EVENT(name) \
+DEFINE_EVENT(dax_pmd_insert_mapping_class, name, \
+ TP_PROTO(struct vm_area_struct *vma, unsigned long address, \
+ int write, long length, pfn_t pfn, void *radix_entry), \
+ TP_ARGS(vma, address, write, length, pfn, radix_entry))
+
+DEFINE_PMD_INSERT_MAPPING_EVENT(dax_pmd_insert_mapping);
+DEFINE_PMD_INSERT_MAPPING_EVENT(dax_pmd_insert_mapping_fallback);
+
#endif /* _TRACE_FS_DAX_H */
/* This part must be outside protection */
--
2.7.4
--
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