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    SubjectRe: 2.6.25-rc7-git2: Reported regressions from 2.6.24


    On Thu, 27 Mar 2008, Christoph Lameter wrote:
    >
    > Slab allocations can never use GFP_HIGHMEM.

    Totally irrelevant.

    The page allocation path does

    if (gfp_flags & __GFP_ZERO)
    prep_zero_page(page, order, gfp_flags);

    and that will cause a warning REGARDLESS of whether the page is a HIGHMEM
    page or not.

    And the fact is, passing in GFP_ZERO from the SLUB code is a bug
    regardless, because it unnecessarily does the dual memset().

    So here's a damn big clue:
    - SLUB does its own GFP_ZERO handling
    - so passing GFP_ZERO down to the page allocator is a f*cking bug
    - and this has NOTHING what-so-ever to do with GFP_HIGHMEM or even
    whether the warning is "valid" or not - it's a bug even if the warning
    had never happened.

    So stop blathering, and just admit that this was buggy. It was also
    fundamentally fragile to leave GFP_ZERO around when it was known to not be
    valid at that point (exactly because GFP_ZERO was handled by the caller).

    Linus


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