Re: [PATCH, RFC] shmat: introduce flag SHM_MAP_HINT

KOSAKI Motohiro
2008-10-07T11:08:21Z

> It allows interpret attach address as a hint, not as exact address.
>
> Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name>
> Cc: Andi Kleen <andi@firstfloor.org>
> Cc: Ingo Molnar <mingo@redhat.com>
> Cc: Arjan van de Ven <arjan@infradead.org>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> ---
> include/linux/shm.h | 1 +
> ipc/shm.c | 4 ++--
> 2 files changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/include/linux/shm.h b/include/linux/shm.h
> index eca6235..2a637b8 100644
> --- a/include/linux/shm.h
> +++ b/include/linux/shm.h
> @@ -55,6 +55,7 @@ struct shmid_ds {
> #define SHM_RND 020000 /* round attach address to SHMLBA boundary */
> #define SHM_REMAP 040000 /* take-over region on attach */
> #define SHM_EXEC 0100000 /* execution access */
> +#define SHM_MAP_HINT 0200000 /* interpret attach address as a hint */

hmm..
Honestly, I don't like that qemu specific feature insert into shmem core.
At least, this patch is too few comments.
Therefore, an develpper can't understand why SHM_MAP_HINT exist.

I think this patch description is too short and too poor.
I don't like increasing mysterious interface.