probe::nfs.fop.sendfile — NFS client send file operation
nfs.fop.sendfile
cache_valid
cache related bit mask flag
dev
device identifier
count
read bytes
ino
inode number
ppos
current position of file
cache_time
when we started read-caching this inode
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.