On Wed 23-11-16 11:44:21, 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-1393 [007] .... 32.133809: dax_pmd_fault: shared mapping read
> address 0x10400000 vm_start 0x10200000 vm_end 0x10600000 pgoff 0x200
> max_pgoff 0x1400
>
> read_big-1393 [007] .... 32.134067: dax_pmd_load_hole: shared mapping
> read address 0x10400000 zero_page ffffea0002b98000 radix_entry 0x1e
>
> read_big-1393 [007] .... 32.134069: dax_pmd_fault_done: shared mapping
> read address 0x10400000 vm_start 0x10200000 vm_end 0x10600000 pgoff 0x200
> max_pgoff 0x1400 NOPAGE
>
> Signed-off-by: Ross Zwisler <ross.zwisler@xxxxxxxxxxxxxxx>
Looks good. You can add:
Reviewed-by: Jan Kara <jack@xxxxxxx>
Honza
> ---
> fs/dax.c | 13 +++++++++----
> include/trace/events/fs_dax.h | 32 ++++++++++++++++++++++++++++++++
> 2 files changed, 41 insertions(+), 4 deletions(-)
>
> diff --git a/fs/dax.c b/fs/dax.c
> index 1aa7616..2824414 100644
> --- a/fs/dax.c
> +++ b/fs/dax.c
> @@ -1269,32 +1269,37 @@ 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 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(vma, address, zero_page, ret);
> return VM_FAULT_NOPAGE;
> +
> +fallback:
> + trace_dax_pmd_load_hole_fallback(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 f9ed4eb..8814b1a 100644
> --- a/include/trace/events/fs_dax.h
> +++ b/include/trace/events/fs_dax.h
> @@ -54,6 +54,38 @@ 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 vm_area_struct *vma, unsigned long address,
> + struct page *zero_page, void *radix_entry),
> + TP_ARGS(vma, address, zero_page, radix_entry),
> + TP_STRUCT__entry(
> + __field(unsigned long, vm_flags)
> + __field(unsigned long, address)
> + __field(struct page *, zero_page)
> + __field(void *, radix_entry)
> + ),
> + TP_fast_assign(
> + __entry->vm_flags = vma->vm_flags;
> + __entry->address = address;
> + __entry->zero_page = zero_page;
> + __entry->radix_entry = radix_entry;
> + ),
> + TP_printk("%s mapping read address %#lx zero_page %p radix_entry %#lx",
> + __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 vm_area_struct *vma, unsigned long address, \
> + struct page *zero_page, void *radix_entry), \
> + TP_ARGS(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
>
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR
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