On Fri, Mar 03, 2023 at 09:39:11PM +0100, Mateusz Guzik wrote:

the allocation routine does not have any information about the size
available at compilation time, so has to resort to a memset call at
runtime. Instead, should this be:

f = kmem_cache_alloc(...);
memset(f, 0, sizeof(*f));

... the compiler could in principle inititalize stuff as indicated by
code and emit zerofill for the rest. Interestingly, last I checked
neither clang nor gcc knew how to do it, they instead resort to a full
sized memset anyway, which is quite a bummer.

For struct file I wouldn't expect a win from that, TBH.