linux-kernel - Re: [RFC PATCH 2/8] mm/madvise: remove unnecessary check on madvise_dontneed

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Date:   Mon, 27 Sep 2021 12:11:43 +0300
From:   "Kirill A. Shutemov" <kirill@...temov.name>
To:     Nadav Amit <nadav.amit@...il.com>
Cc:     Andrew Morton <akpm@...ux-foundation.org>, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org, Peter Xu <peterx@...hat.com>,
        Nadav Amit <namit@...are.com>,
        Andrea Arcangeli <aarcange@...hat.com>,
        Minchan Kim <minchan@...nel.org>,
        Colin Cross <ccross@...gle.com>,
        Suren Baghdasarya <surenb@...gle.com>,
        Mike Rapoport <rppt@...ux.vnet.ibm.com>
Subject: Re: [RFC PATCH 2/8] mm/madvise: remove unnecessary check on
 madvise_dontneed_free()

On Sun, Sep 26, 2021 at 09:12:53AM -0700, Nadav Amit wrote:
> From: Nadav Amit <namit@...are.com>
> 
> madvise_dontneed_free() is called only from madvise_vma() and the
> behavior is always either MADV_FREE or MADV_DONTNEED. There is no need
> to check again in madvise_dontneed_free() if the behavior is any
> different.

So what. The check is free. Compiler should be clever enough to eliminate
the additional check. If there's a new MADV_DONTNEED flavour, the change
would have to be effectively reverted.

NAK.

-- 
 Kirill A. Shutemov