Messages in this thread | | | Date | Mon, 23 Jul 2007 15:50:07 -0700 (PDT) | From | Christoph Lameter <> | Subject | Re: [PATCH] add __GFP_ZERP to GFP_LEVEL_MASK |
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On Mon, 23 Jul 2007, Andrew Morton wrote:
> On Mon, 23 Jul 2007 14:43:23 -0700 > Christoph Lameter <clameter@sgi.com> wrote: > > > __GFP_ZERO is implemented by the slab allocators (the page allocator > > has no knowledge about the length of the object to be zeroed). The slab > > allocators do not pass __GFP_ZERO to the page allocator. > > OK, well that was weird. So > > kmalloc(42, GFP_KERNEL|__GFP_ZERO); > > duplicates > > kzalloc(42, GFP_KERNEL);
Correct.
> Why do it both ways?
There are now ~2.5k uses of kzalloc in the kernel.
kzalloc and friends implies that we need to duplicate all allocator functions. That was never done for NUMA allocators there was never a kzalloc_node f.e..
kzalloc also cannot be used in a parameterized way in a derived allocator where you would simply pass on the gfp flags.
__GFP_ZERO support allows all allocators to work in a consistent way. There is no need to special case slab zeroing allocation.
kzalloc could be removed.
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