Re: [PATCH v2 3/6] dax: add tracepoint infrastructure, PMD tracing

[Steven Rostedt]

On Wed, 30 Nov 2016 16:45:30 -0700
Ross Zwisler <ross.zwisler@xxxxxxxxxxxxxxx> wrote:


> --- /dev/null
> +++ b/include/trace/events/fs_dax.h
> @@ -0,0 +1,68 @@
> +#undef TRACE_SYSTEM
> +#define TRACE_SYSTEM fs_dax
> +
> +#if !defined(_TRACE_FS_DAX_H) || defined(TRACE_HEADER_MULTI_READ)
> +#define _TRACE_FS_DAX_H
> +
> +#include <linux/tracepoint.h>
> +
> +DECLARE_EVENT_CLASS(dax_pmd_fault_class,
> +	TP_PROTO(struct inode *inode, struct vm_area_struct *vma,
> +		unsigned long address, unsigned int flags, pgoff_t pgoff,
> +		pgoff_t max_pgoff, int result),
> +	TP_ARGS(inode, vma, address, flags, pgoff, max_pgoff, result),
> +	TP_STRUCT__entry(
> +		__field(dev_t, dev)
> +		__field(unsigned long, ino)
> +		__field(unsigned long, vm_start)
> +		__field(unsigned long, vm_end)
> +		__field(unsigned long, vm_flags)
> +		__field(unsigned long, address)
> +		__field(unsigned int, flags)
> +		__field(pgoff_t, pgoff)
> +		__field(pgoff_t, max_pgoff)
> +		__field(int, result)

For better compaction, I would put flags and result together, as they
are both ints. Otherwise, you'll probably have 4 empty bytes after
flags.

-- Steve

> +	),
> +	TP_fast_assign(
> +		__entry->dev = inode->i_sb->s_dev;
> +		__entry->ino = inode->i_ino;
> +		__entry->vm_start = vma->vm_start;
> +		__entry->vm_end = vma->vm_end;
> +		__entry->vm_flags = vma->vm_flags;
> +		__entry->address = address;
> +		__entry->flags = flags;
> +		__entry->pgoff = pgoff;
> +		__entry->max_pgoff = max_pgoff;
> +		__entry->result = result;
> +	),
> +	TP_printk("dev %d:%d ino %#lx %s %s address %#lx vm_start "
> +			"%#lx vm_end %#lx pgoff %#lx max_pgoff %#lx %s",
> +		MAJOR(__entry->dev),
> +		MINOR(__entry->dev),
> +		__entry->ino,
> +		__entry->vm_flags & VM_SHARED ? "shared" : "private",
> +		__print_flags(__entry->flags, "|", FAULT_FLAG_TRACE),
> +		__entry->address,
> +		__entry->vm_start,
> +		__entry->vm_end,
> +		__entry->pgoff,
> +		__entry->max_pgoff,
> +		__print_flags(__entry->result, "|", VM_FAULT_RESULT_TRACE)
> +	)
> +)
> +
> +#define DEFINE_PMD_FAULT_EVENT(name) \
> +DEFINE_EVENT(dax_pmd_fault_class, name, \
> +	TP_PROTO(struct inode *inode, struct vm_area_struct *vma, \
> +		unsigned long address, unsigned int flags, pgoff_t pgoff, \
> +		pgoff_t max_pgoff, int result), \
> +	TP_ARGS(inode, vma, address, flags, pgoff, max_pgoff, result))
> +
> +DEFINE_PMD_FAULT_EVENT(dax_pmd_fault);
> +DEFINE_PMD_FAULT_EVENT(dax_pmd_fault_done);
> +
> +
> +#endif /* _TRACE_FS_DAX_H */
> +
> +/* This part must be outside protection */
> +#include <trace/define_trace.h>