UFFDIO_CONTINUE(2const) — Linux manual page

NAME | LIBRARY | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | STANDARDS | HISTORY | EXAMPLES | SEE ALSO | COLOPHON

UFFDIO_CONTINUE(2const)                          UFFDIO_CONTINUE(2const)

NAME         top

       UFFDIO_CONTINUE - resolve a minor page fault

LIBRARY         top

       Standard C library (libc, -lc)

SYNOPSIS         top

       #include <linux/userfaultfd.h>  /* Definition of UFFD* constants */
       #include <sys/ioctl.h>

       int ioctl(int fd, UFFDIO_CONTINUE, struct uffdio_continue *argp);

       #include <linux/userfaultfd.h>

       struct uffdio_continue {
           struct uffdio_range  range;
                            /* Range to install PTEs for and continue */
           __u64   mode;    /* Flags controlling the behavior of continue */
           __s64   mapped;  /* Number of bytes mapped, or negated error */
       };

DESCRIPTION         top

       Resolve a minor page fault by installing page table entries for
       existing pages in the page cache.

       The following value may be bitwise ORed in mode to change the
       behavior of the UFFDIO_CONTINUE operation:

       UFFDIO_CONTINUE_MODE_DONTWAKE
              Do not wake up the thread that waits for page-fault
              resolution.

       The mapped field is used by the kernel to return the number of
       bytes that were actually mapped, or an error in the same manner
       as UFFDIO_COPY.  If the value returned in the mapped field
       doesn't match the value that was specified in range.len, the
       operation fails with the error EAGAIN.  The mapped field is
       output-only; it is not read by the UFFDIO_CONTINUE operation.

RETURN VALUE         top

       This ioctl(2) operation returns 0 on success.  In this case, the
       entire area was mapped.  On error, -1 is returned and errno is
       set to indicate the error.

ERRORS         top

       EAGAIN The number of bytes mapped (i.e., the value returned in
              the mapped field) does not equal the value that was
              specified in the range.len field.

       EEXIST One or more pages were already mapped in the given range.

       EFAULT No existing page could be found in the page cache for the
              given range.

       EINVAL Either range.start or range.len was not a multiple of the
              system page size; or range.len was zero; or the range
              specified was invalid.

       EINVAL An invalid bit was specified in the mode field.

       ENOENT The faulting process has changed its virtual memory layout
              simultaneously with an outstanding UFFDIO_CONTINUE
              operation.

       ENOMEM Allocating memory needed to setup the page table mappings
              failed.

       ESRCH  The faulting process has exited at the time of a
              UFFDIO_CONTINUE operation.

STANDARDS         top

       Linux.

HISTORY         top

       Linux 5.13.

EXAMPLES         top

       See userfaultfd(2).

SEE ALSO         top

       ioctl(2), ioctl_userfaultfd(2), userfaultfd(2)

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

COLOPHON         top

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Linux man-pages 6.9.1          2024-06-17        UFFDIO_CONTINUE(2const)

Pages that refer to this page: ioctl_userfaultfd(2)