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Date:   Wed, 16 Mar 2022 14:29:06 -0700
From:   Andrew Morton <akpm@linux-foundation.org>
To:     Charan Teja Kalla <quic_charante@quicinc.com>
Cc:     Minchan Kim <minchan@kernel.org>, <surenb@google.com>,
        <vbabka@suse.cz>, <rientjes@google.com>, <sfr@canb.auug.org.au>,
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        <mhocko@suse.com>, <linux-mm@kvack.org>,
        <linux-kernel@vger.kernel.org>,
        "# 5 . 10+" <stable@vger.kernel.org>
Subject: Re: [PATCH V2,2/2] mm: madvise: skip unmapped vma holes passed to
 process_madvise
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On Wed, 16 Mar 2022 19:49:38 +0530 Charan Teja Kalla <quic_charante@quicinc.com> wrote:

> > IMO, it's worth to note in man page.
> > 
> 
> Or the current patch for just ENOMEM is sufficient here and we just have
> to update the man page?

I think the "On success, process_madvise() returns the number of bytes
advised" behaviour sounds useful.  But madvise() doesn't do that.

RETURN VALUE
       On  success, madvise() returns zero.  On error, it returns -1 and errno
       is set to indicate the error.

So why is it desirable in the case of process_madvise()?


And why was process_madvise() designed this way?   Or was it
always simply an error in the manpage?