> From: David Cohen > On Wed, Dec 18, 2013 at 11:24:47AM -0000, David Laight wrote: > > This saves a kzalloc() call on every transfer and some memory > > indirections. > > > > The only possible downside is for isochronous tranfers with 64 td > > when the allocate is 8+4096 bytes (on 64bit systems) so requires > > an additional page. > > If you take this to embedded world there could be a bad side effect too. > The free memory isn't abundant and the fragmentation may make a bigger > kmalloc() to cost more than 2 smaller ones. The effect of this change is really to remove the first allocation and add 8 bytes (or maybe a pointer) to the start of the second one. So it is extremely unlikely to fail when the old code would work. It would, of course, be better to allocate a parallel 'software' ring containing the required extra information and completely remove the additional allocate/free on every USB request. David -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
