On Fri, 2015-08-28 at 16:12 -0700, Joe Perches wrote: > Generally true. It's always difficult to know how much > stack has been consumed though and smaller stack frames > are generally better.
Calling kmalloc(288, GFP_KERNEL) might use way more than 288 bytes in kernel stack on 64 bit arch. __slab_alloc() itself for example uses 208 bytes on stack, so add all others, and you might go above 500 bytes. So for a _leaf_ function, it is better to declare an automatic variable, as you in fact reduce max stack depth. Not only it uses less kernel stack, it is also way faster, as you avoid kmalloc()/kfree() overhead and reuse probably already hot cache lines in kernel stack. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
