NAME¶

PAGEMAP_SCAN - get and/or clear page flags

LIBRARY¶

Standard C library (libc, -lc)

SYNOPSIS¶

#include <linux/fs.h>  /* Definition of PAGE* and PM_* constants */
#include <sys/ioctl.h>

int ioctl(int pagemap_fd, PAGEMAP_SCAN, struct pm_scan_arg *arg);

#include <linux/fs.h>

struct pm_scan_arg {
    __u64  size;
    __u64  flags;
    __u64  start;
    __u64  end;
    __u64  walk_end;
    __u64  vec;
    __u64  vec_len;
    __u64  max_pages;
    __u64  category_inverted;
    __u64  category_mask;
    __u64  category_anyof_mask;
    __u64  return_mask;
};

struct page_region {
    __u64  start;
    __u64  end;
    __u64  categories;
};

DESCRIPTION¶

This ioctl(2) is used to get and optionally clear some specific flags from page table entries. The information is returned with PAGE_SIZE granularity.

To start tracking the written state (flag) of a page or range of memory, the UFFD_FEATURE_WP_ASYNC must be enabled by UFFDIO_API ioctl(2) on userfaultfd and memory range must be registered with UFFDIO_REGISTER ioctl(2) in UFFDIO_REGISTER_MODE_WP mode.

RETURN VALUE¶

On error, -1 is returned, and errno is set to indicate the error.

ERRORS¶

Error codes can be one of, but are not limited to, the following:

EINVAL

Invalid arguments i.e., invalid size of the argument, invalid flags, invalid categories, the start address isn't aligned with PAGE_SIZE, or vec_len is specified when vec is NULL.

EFAULT

Invalid arg pointer, invalid vec pointer, or invalid address range specified by start and end.

ENOMEM

No memory is available.

EINTR

Fetal signal is pending.

STANDARDS¶

Linux.

HISTORY¶

Linux 6.7.

SEE ALSO¶

ioctl(2)