cachestat

query the page cache statistics of a file

sys_cachestat(unsigned int fd, struct cachestat_range *cstat_range, struct cachestat *cstat, unsigned int flags)

register	value
`x8`	451, the syscall number
`x0`	unsigned int fd
`x1`	struct cachestat_range *cstat_range
`x2`	struct cachestat *cstat
`x3`	unsigned int flags
`x0`	the return value

Then run svc #0 to enter the kernel.

Same syscall on other architectures