On 09/28/2012 02:56 AM, David Rientjes wrote: > On Thu, 27 Sep 2012, Glauber Costa wrote: > >> But I still don't see the big reason for your objection. If other >> allocator start using those bits, they would not be passed to >> kmem_cache_alloc anyway, right? So what would be the big problem in >> masking them out before it? >> > > A slab allocator implementation may allow for additional bits that are > currently not used or used for internal purposes by the current set of > slab allocators to be passed in the unsigned long to kmem_cache_create() > that would be a no-op on other allocators. It's implementation defined, > so this masking should be done in the implementation, i.e. > __kmem_cache_create(). > > For context, as many people who attended the kernel summit and LinuxCon > are aware, a new slab allocator is going to be proposed soon that actually > uses additional bits that aren't defined for all slab allocators. My > opinion is that leaving unused bits and reserved bits to the > implementation is the best software engineering practice. > I am happy as long as we don't BUG and can mask out that feature. If Christoph is happy with me masking it in the SLAB only, I'm also fine. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>