Re: [PATCH 5/8] mm: follow_hugetlb_page flags

From: Rik van Riel
Date: Tue Sep 08 2009 - 18:22:25 EST


Hugh Dickins wrote:
follow_hugetlb_page() shouldn't be guessing about the coredump case
either: pass the foll_flags down to it, instead of just the write bit.

Remove that obscure huge_zeropage_ok() test. The decision is easy,
though unlike the non-huge case - here vm_ops->fault is always set.
But we know that a fault would serve up zeroes, unless there's
already a hugetlbfs pagecache page to back the range.

(Alternatively, since hugetlb pages aren't swapped out under pressure,
you could save more dump space by arguing that a page not yet faulted
into this process cannot be relevant to the dump; but that would be
more surprising.)

Signed-off-by: Hugh Dickins <hugh.dickins@xxxxxxxxxxxxx>

Acked-by: Rik van Riel <riel@xxxxxxxxxx>

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