Re: [PATCH 1/2] slab: __GFP_ZERO is incompatible with a constructor

On 04/10/2018 05:53 AM, Matthew Wilcox wrote:

From: Matthew Wilcox mawilcox@microsoft.com

__GFP_ZERO requests that the object be initialised to all-zeroes, while the purpose of a constructor is to initialise an object to a particular pattern. We cannot do both. Add a warning to catch any users who mistakenly pass a __GFP_ZERO flag when allocating a slab with a constructor.

Fixes: d07dbea46405 ("Slab allocators: support __GFP_ZERO in all allocators") Signed-off-by: Matthew Wilcox mawilcox@microsoft.com Cc: stable@vger.kernel.org

Since there are probably no bug to fix, what about adding the extra check only for some DEBUG option ?

How many caches are still using ctor these days ?