dax: add tracepoints to dax_pfn_mkwrite()

Add tracepoints to dax_pfn_mkwrite(), following the same logging
conventions as the rest of DAX.

Here is an example PTE fault followed by a pfn_mkwrite:

  small_aligned-1094  [002] ....
   374.084998: dax_pte_fault: dev 259:0 ino 0x1003 shared WRITE|ALLOW_RETRY|KILLABLE|USER address 0x10400000 pgoff 0x200

  small_aligned-1094  [002] ....
   374.085145: dax_pte_fault_done: dev 259:0 ino 0x1003 shared WRITE|ALLOW_RETRY|KILLABLE|USER address 0x10400000 pgoff 0x200 MAJOR|NOPAGE

  small_aligned-1094  [002] ....
   374.085165: dax_pfn_mkwrite: dev 259:0 ino 0x1003 shared WRITE|MKWRITE|ALLOW_RETRY|KILLABLE|USER address 0x10400000 pgoff 0x200 NOPAGE

Link: http://lkml.kernel.org/r/20170221195116.13278-3-ross.zwisler@linux.intel.com
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/fs/dax.c b/fs/dax.c
index f6c32d831af6e4d55526dfb714fe7d78c2b0f7b1..d10524ab7e5548ac13402ae93b7c37b16df6c615 100644 (file)
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -927,6 +927,7 @@ int dax_pfn_mkwrite(struct vm_fault *vmf)
 {
        struct file *file = vmf->vma->vm_file;
        struct address_space *mapping = file->f_mapping;
+       struct inode *inode = mapping->host;
        void *entry, **slot;
        pgoff_t index = vmf->pgoff;
 
@@ -936,6 +937,7 @@ int dax_pfn_mkwrite(struct vm_fault *vmf)
                if (entry)
                        put_unlocked_mapping_entry(mapping, index, entry);
                spin_unlock_irq(&mapping->tree_lock);
+               trace_dax_pfn_mkwrite_no_entry(inode, vmf, VM_FAULT_NOPAGE);
                return VM_FAULT_NOPAGE;
        }
        radix_tree_tag_set(&mapping->page_tree, index, PAGECACHE_TAG_DIRTY);
@@ -948,6 +950,7 @@ int dax_pfn_mkwrite(struct vm_fault *vmf)
         */
        finish_mkwrite_fault(vmf);
        put_locked_mapping_entry(mapping, index, entry);
+       trace_dax_pfn_mkwrite(inode, vmf, VM_FAULT_NOPAGE);
        return VM_FAULT_NOPAGE;
 }
 EXPORT_SYMBOL_GPL(dax_pfn_mkwrite);

diff --git a/include/trace/events/fs_dax.h b/include/trace/events/fs_dax.h
index cbcd7d64a18de4184ab708f2317b38ab3152f185..b5a520961f8d9958657ae872ab13b713a5a02f57 100644 (file)
--- a/include/trace/events/fs_dax.h
+++ b/include/trace/events/fs_dax.h
@@ -190,6 +190,8 @@ DEFINE_EVENT(dax_pte_fault_class, name, \
 
 DEFINE_PTE_FAULT_EVENT(dax_pte_fault);
 DEFINE_PTE_FAULT_EVENT(dax_pte_fault_done);
+DEFINE_PTE_FAULT_EVENT(dax_pfn_mkwrite_no_entry);
+DEFINE_PTE_FAULT_EVENT(dax_pfn_mkwrite);
 
 #endif /* _TRACE_FS_DAX_H */