* Re: [patch] memfd_create.2: Add description of MFD_HUGETLB (hugetlbfs) support
[not found] <20170915214305.7148-1-mike.kravetz@oracle.com>
@ 2017-09-15 21:54 ` Mike Kravetz
2017-09-21 13:03 ` Michael Kerrisk (man-pages)
1 sibling, 0 replies; 2+ messages in thread
From: Mike Kravetz @ 2017-09-15 21:54 UTC (permalink / raw)
To: mtk.manpages
Cc: linux-man, linux-kernel, linux-api, Michal Hocko, Hugh Dickins,
Andrea Arcangeli, Kirill A . Shutemov, linux-mm
CC: linux-mm
On 09/15/2017 02:43 PM, Mike Kravetz wrote:
> hugetlbfs support for memfd_create was recently merged by Linus and
> should be in the Linux 4.14 release. To request hugetlbfs support
> a new memfd_create flag (MFD_HUGETLB) was added.
>
> This patch documents the following commit:
>
> commit 749df87bd7bee5a79cef073f5d032ddb2b211de8
> Author: Mike Kravetz <mike.kravetz@oracle.com>
> Date: Wed Sep 6 16:24:16 2017 -0700
>
> mm/shmem: add hugetlbfs support to memfd_create()
>
> Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
> ---
> man2/memfd_create.2 | 27 +++++++++++++++++++++++++++
> 1 file changed, 27 insertions(+)
>
> diff --git a/man2/memfd_create.2 b/man2/memfd_create.2
> index 4dfd1bb2d..b61254bb8 100644
> --- a/man2/memfd_create.2
> +++ b/man2/memfd_create.2
> @@ -100,6 +100,33 @@ If this flag is not set, the initial set of seals will be
> meaning that no other seals can be set on the file.
> .\" FIXME Why is the MFD_ALLOW_SEALING behavior not simply the default?
> .\" Is it worth adding some text explaining this?
> +.TP
> +.BR MFD_HUGETLB " (since Linux 4.14)"
> +The anonymous file will be created in the hugetlbfs filesystem using
> +huge pages. See the Linux kernel source file
> +.I Documentation/vm/hugetlbpage.txt
> +for more information about hugetlbfs. The hugetlbfs filesystem does
> +not support file sealing operations. Therefore, specifying both
> +.B MFD_HUGETLB
> +and
> +.B MFD_ALLOW_SEALING
> +will result in an error
> +.RB (EINVAL)
> +being returned.
> +
> +.TP
> +.BR MFD_HUGE_2MB ", " MFD_HUGE_1GB ", " "..."
> +Used in conjunction with
> +.B MFD_HUGETLB
> +to select alternative hugetlb page sizes (respectively, 2 MB, 1 GB, ...)
> +on systems that support multiple hugetlb page sizes. Definitions for known
> +huge page sizes are included in the header file
> +.I <sys/memfd.h>.
> +
> +For details on encoding huge page sizes not included in the header file,
> +see the discussion of the similarly named constants in
> +.BR mmap (2).
> +
> .PP
> Unused bits in
> .I flags
>
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^ permalink raw reply [flat|nested] 2+ messages in thread* Re: [patch] memfd_create.2: Add description of MFD_HUGETLB (hugetlbfs) support
[not found] <20170915214305.7148-1-mike.kravetz@oracle.com>
2017-09-15 21:54 ` [patch] memfd_create.2: Add description of MFD_HUGETLB (hugetlbfs) support Mike Kravetz
@ 2017-09-21 13:03 ` Michael Kerrisk (man-pages)
1 sibling, 0 replies; 2+ messages in thread
From: Michael Kerrisk (man-pages) @ 2017-09-21 13:03 UTC (permalink / raw)
To: Mike Kravetz
Cc: mtk.manpages, linux-man, linux-kernel, linux-api, Michal Hocko,
Hugh Dickins, Andrea Arcangeli, Kirill A . Shutemov,
linux-mm@kvack.org
Hi Mike,
On 09/15/2017 11:43 PM, Mike Kravetz wrote:
> hugetlbfs support for memfd_create was recently merged by Linus and
> should be in the Linux 4.14 release. To request hugetlbfs support
> a new memfd_create flag (MFD_HUGETLB) was added.
>
> This patch documents the following commit:
>
> commit 749df87bd7bee5a79cef073f5d032ddb2b211de8
> Author: Mike Kravetz <mike.kravetz@oracle.com>
> Date: Wed Sep 6 16:24:16 2017 -0700
>
> mm/shmem: add hugetlbfs support to memfd_create()
Thanks! I've applied this patch.
Cheers,
Michael
>
> Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
> ---
> man2/memfd_create.2 | 27 +++++++++++++++++++++++++++
> 1 file changed, 27 insertions(+)
>
> diff --git a/man2/memfd_create.2 b/man2/memfd_create.2
> index 4dfd1bb2d..b61254bb8 100644
> --- a/man2/memfd_create.2
> +++ b/man2/memfd_create.2
> @@ -100,6 +100,33 @@ If this flag is not set, the initial set of seals will be
> meaning that no other seals can be set on the file.
> .\" FIXME Why is the MFD_ALLOW_SEALING behavior not simply the default?
> .\" Is it worth adding some text explaining this?
> +.TP
> +.BR MFD_HUGETLB " (since Linux 4.14)"
> +The anonymous file will be created in the hugetlbfs filesystem using
> +huge pages. See the Linux kernel source file
> +.I Documentation/vm/hugetlbpage.txt
> +for more information about hugetlbfs. The hugetlbfs filesystem does
> +not support file sealing operations. Therefore, specifying both
> +.B MFD_HUGETLB
> +and
> +.B MFD_ALLOW_SEALING
> +will result in an error
> +.RB (EINVAL)
> +being returned.
> +
> +.TP
> +.BR MFD_HUGE_2MB ", " MFD_HUGE_1GB ", " "..."
> +Used in conjunction with
> +.B MFD_HUGETLB
> +to select alternative hugetlb page sizes (respectively, 2 MB, 1 GB, ...)
> +on systems that support multiple hugetlb page sizes. Definitions for known
> +huge page sizes are included in the header file
> +.I <sys/memfd.h>.
> +
> +For details on encoding huge page sizes not included in the header file,
> +see the discussion of the similarly named constants in
> +.BR mmap (2).
> +
> .PP
> Unused bits in
> .I flags
>
--
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/
--
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^ permalink raw reply [flat|nested] 2+ messages in thread