Re: [PATCH v3 2/2] vfs: avoid duplicating creds in faccessat if possible

[Al Viro]

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.