Re: [PATCH] mm: msync: require either MS_ASYNC or MS_SYNC

On 04/03/2014 01:51 PM, Christopher Covington wrote:

On 04/03/2014 04:25 AM, Michael Kerrisk (man-pages) wrote:

quoted

I think the only reasonable solution is to better document existing
behavior and what the programmer should do. With that in mind, I've
drafted the following text for the msync(2) man page:

    NOTES
       According to POSIX, exactly one of MS_SYNC and MS_ASYNC  must  be
       specified  in  flags.   However,  Linux permits a call to msync()
       that specifies neither of these flags, with  semantics  that  are
       (currently)  equivalent  to  specifying  MS_ASYNC.   (Since Linux
       2.6.19, MS_ASYNC is in fact a no-op, since  the  kernel  properly
       tracks  dirty  pages  and  flushes them to storage as necessary.)
       Notwithstanding the Linux behavior, portable, future-proof appli‐
       cations  should  ensure  that they specify exactly one of MS_SYNC
       and MS_ASYNC in flags.

Nit: MS_SYNC or MS_ASYNC

Thanks. Reworded.

Cheers,

Michael

-- 
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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