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UFFDIO_WAKE

wake up a thread waiting for page-fault resolution

Standard C library (libc, -lc)

#include <linux/userfaultfd.h>  /* Definition of UFFD* constants */
#include <sys/ioctl.h>
int ioctl(int fd, UFFDIO_WAKE, const struct uffdio_range *argp);

Wake up the thread waiting for page-fault resolution on a specified memory address range.

The UFFDIO_WAKE operation is used in conjunction with UFFDIO_COPY and UFFDIO_ZEROPAGE operations that have the UFFDIO_COPY_MODE_DONTWAKE or UFFDIO_ZEROPAGE_MODE_DONTWAKE bit set in the mode field. The userfault monitor can perform several UFFDIO_COPY and UFFDIO_ZEROPAGE operations in a batch and then explicitly wake up the faulting thread using UFFDIO_WAKE.

This ioctl(2) operation returns 0 on success. On error, -1 is returned and errno is set to indicate the error.

The start or the len field of the ufdio_range structure was not a multiple of the system page size; or len was zero; or the specified range was otherwise invalid.

Linux.

Linux 4.3.

See userfaultfd(2).

ioctl(2), ioctl_userfaultfd(2), UFFDIO_REGISTER(2const), userfaultfd(2)

linux.git/Documentation/admin-guide/mm/userfaultfd.rst