Re: [PATCH] add __GFP_ZERO to GFP_LEVEL_MASK

From: Christoph Lameter
Date: Tue Jul 24 2007 - 03:10:31 EST


On Tue, 24 Jul 2007, Peter Zijlstra wrote:

> Then we can either fixup the slab allocators to mask out __GFP_ZERO, or
> do something like the below.
>
> Personally I like the consistency of adding __GFP_ZERO here (removes
> this odd exception) and just masking it in the sl[aou]b thingies.

There is another exception for __GFP_DMA.

> Anybody else got a preference?

> #define __GFP_BITS_MASK ((__force gfp_t)((1 << __GFP_BITS_SHIFT) - 1))
>
> -/* if you forget to add the bitmask here kernel will crash, period */
> +/*
> + * If you forget to add the bitmask here kernel will crash, period!
> + *
> + * GFP_LEVEL_MASK is used to filter out the flags that are to be passed to the
> + * page allocator.
> + *

GFP_LEVEL_MASK is also used in mm/vmalloc.c. We need a definition that
goes beyond slab allocators.

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