Re: [PATCH] madvise.2: madvise(, , MADV_REMOVE) supports ext4, ocfs2 and xfs as well

[Jan Chaloupka <jchaloup-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>]

ping

On 10/18/2014 05:22 PM, Jan Chaloupka wrote:
> As from upstream commit:
>
> commit 3f31d07571eeea18a7d34db9af21d2285b807a17
> Author: Hugh Dickins <hughd-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
> Date:   Tue May 29 15:06:40 2012 -0700
>
>       mm/fs: route MADV_REMOVE to FALLOC_FL_PUNCH_HOLE
>
>       Now tmpfs supports hole-punching via fallocate(), switch madvise_remove()
>       to use do_fallocate() instead of vmtruncate_range(): which extends
>       madvise(,,MADV_REMOVE) support from tmpfs to ext4, ocfs2 and xfs.
>
> madvise(,,MADV_REMOVE) support was extended by ext4, ocfs2 and xfs.
>
> bug report: https://bugzilla.redhat.com/show_bug.cgi?id=1120294
>
> Justification from Rafael Aquini:
> Well, that code is committed in kernel since v3.5 (2012) and it surely is
> the expected behaviour since. It seems to me that madvise(2) man page text
> for MADV_REMOVE just got out-of-date in that regard.
>
> This patch mentions this support in madvise.2 man page.
>
> Reworded and corrected by Michael Kerrisk and Hugh Dickins. Thank you.
>
> Signed-off-by: Jan Chaloupka <jchaloup-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
> ---
>   man2/madvise.2 |   17 ++++++++++++-----
>   1 file changed, 12 insertions(+), 5 deletions(-)
>
> diff --git a/man2/madvise.2 b/man2/madvise.2
> index 032ead7..b955864 100644
> --- a/man2/madvise.2
> +++ b/man2/madvise.2
> @@ -101,11 +101,18 @@ without an underlying file.
>   .BR MADV_REMOVE " (since Linux 2.6.16)"
>   Free up a given range of pages
>   and its associated backing store.
> -Currently,
> -.\" 2.6.18-rc5
> -only shmfs/tmpfs supports this; other filesystems return with the
> -error
> -.BR ENOSYS .
> +Originally, only shmfs/tmpfs supported this; but since Linux 3.5,
> +any filesystem which supports the
> +.BR fallocate(2)
> +mode
> +.BR FALLOC_FL_PUNCH_HOLE
> +also supports the
> +.BR madvise(2)
> +advice
> +.BR MADV_REMOVE .
> +Other filesystems return with the
> +.BR EOPNOTSUPP
> +error.
>   .\" Databases want to use this feature to drop a section of their
>   .\" bufferpool (shared memory segments) - without writing back to
>   .\" disk/swap space.  This feature is also useful for supporting
>
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