[patch] madvise.2: specify MADV_REMOVE returns EINVAL for hugetlbfs

[patch] madvise.2: specify MADV_REMOVE returns EINVAL for hugetlbfs

[David Rientjes]

madvise(2) actually returns with error EINVAL for MADV_REMOVE when used 
for hugetlb vmas, not EOPNOTSUPP, and this has been the case since 
MADV_REMOVE was introduced in commit f6b3ec238d12 ("madvise(MADV_REMOVE): 
remove pages from tmpfs shm backing store").

Specify the exact behavior.

Signed-off-by: David Rientjes <rientjes@google.com>
---
 man2/madvise.2 | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/man2/madvise.2 b/man2/madvise.2
index a3d93bb..00db39d 100644
--- a/man2/madvise.2
+++ b/man2/madvise.2
@@ -184,7 +184,9 @@ any filesystem which supports the
 .BR FALLOC_FL_PUNCH_HOLE
 mode also supports
 .BR MADV_REMOVE .
-Other filesystems fail with the error
+Hugetlbfs will fail with the error
+.BR EINVAL
+and other filesystems fail with the error
 .BR EOPNOTSUPP .
 .TP
 .BR MADV_DONTFORK " (since Linux 2.6.16)"

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Re: [patch] madvise.2: specify MADV_REMOVE returns EINVAL for hugetlbfs

[Michael Kerrisk (man-pages)]

On 04/02/2015 11:21 PM, David Rientjes wrote:
> madvise(2) actually returns with error EINVAL for MADV_REMOVE when used 
> for hugetlb vmas, not EOPNOTSUPP, and this has been the case since 
> MADV_REMOVE was introduced in commit f6b3ec238d12 ("madvise(MADV_REMOVE): 
> remove pages from tmpfs shm backing store").

Thanks David. Applied. I'd already fixed the appropriate piece in
the ERRORS list a while back, but missed that piece in the main text.

Cheers,

Michael


> Specify the exact behavior.
> 
> Signed-off-by: David Rientjes <rientjes@google.com>
> ---
>  man2/madvise.2 | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/man2/madvise.2 b/man2/madvise.2
> index a3d93bb..00db39d 100644
> --- a/man2/madvise.2
> +++ b/man2/madvise.2
> @@ -184,7 +184,9 @@ any filesystem which supports the
>  .BR FALLOC_FL_PUNCH_HOLE
>  mode also supports
>  .BR MADV_REMOVE .
> -Other filesystems fail with the error
> +Hugetlbfs will fail with the error
> +.BR EINVAL
> +and other filesystems fail with the error
>  .BR EOPNOTSUPP .
>  .TP
>  .BR MADV_DONTFORK " (since Linux 2.6.16)"
> 


-- 
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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