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NAME | LIBRARY | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | STANDARDS | HISTORY | EXAMPLES | SEE ALSO | COLOPHON |
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UFFDIO_ZEROPAGE(2const) UFFDIO_ZEROPAGE(2const)
UFFDIO_ZEROPAGE - zero out a memory range registered with
userfaultfd
Standard C library (libc, -lc)
#include <linux/userfaultfd.h> /* Definition of UFFD* constants */
#include <sys/ioctl.h>
int ioctl(int fd, UFFDIO_ZEROPAGE, struct uffdio_zeropage *argp);
#include <linux/userfaultfd.h>
struct uffdio_zeropage {
struct uffdio_range range;
__u64 mode; /* Flags controlling behavior */
__s64 zeropage; /* Number of bytes zeroed */
};
Zero out a memory range registered with userfaultfd.
The following value may be bitwise ORed in mode to change the
behavior of the UFFDIO_ZEROPAGE operation:
UFFDIO_ZEROPAGE_MODE_DONTWAKE
Do not wake up the thread that waits for page-fault
resolution.
The zeropage field is used by the kernel to return the number of
bytes that was actually zeroed, or an error in the same manner as
UFFDIO_COPY. If the value returned in the zeropage field doesn't
match the value that was specified in range.len, the operation
fails with the error EAGAIN. The zeropage field is output-only;
it is not read by the UFFDIO_ZEROPAGE operation.
This ioctl(2) operation returns 0 on success. In this case, the
entire area was zeroed. On error, -1 is returned and errno is set
to indicate the error.
EAGAIN The number of bytes zeroed (i.e., the value returned in the
zeropage field) does not equal the value that was specified
in the range.len field.
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.
ESRCH (since Linux 4.13)
The faulting process has exited at the time of a
UFFDIO_ZEROPAGE operation.
Linux.
Linux 4.3.
See userfaultfd(2).
ioctl(2), ioctl_userfaultfd(2), userfaultfd(2)
linux.git/Documentation/admin-guide/mm/userfaultfd.rst
This page is part of the man-pages (Linux kernel and C library
user-space interface documentation) project. Information about
the project can be found at
⟨https://www.kernel.org/doc/man-pages/⟩. If you have a bug report
for this manual page, see
⟨https://git.kernel.org/pub/scm/docs/man-pages/man-pages.git/tree/CONTRIBUTING⟩.
This page was obtained from the tarball man-pages-6.15.tar.gz
fetched from
⟨https://mirrors.edge.kernel.org/pub/linux/docs/man-pages/⟩ on
2025-08-11. If you discover any rendering problems in this HTML
version of the page, or you believe there is a better or more up-
to-date source for the page, or you have corrections or
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part of the original manual page), send a mail to
man-pages@man7.org
Linux man-pages 6.15 2025-05-17 UFFDIO_ZEROPAGE(2const)
Pages that refer to this page: ioctl_userfaultfd(2)
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HTML rendering created 2025-09-06 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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