probe::nfs.fop.sendfile — NFS client send file operation
nfs.fop.sendfile
cache_time
when we started read-caching this inode
count
read bytes
ppos
current position of file
ino
inode number
cache_valid
cache related bit mask flag
dev
device identifier
attrtimeo
how long the cached information is assumed to be valid. We need to revalidate the cached attrs for this inode if jiffies - read_cache_jiffies > attrtimeo.