Re: [PATCH] audit: remove the audit freelist
Paul Moore <paul(a)paul-moore.com> wrote:
On Tue, Nov 15, 2016 at 8:16 AM, Florian Westphal
<fw(a)strlen.de> wrote:
> allows better debugging as freeing audit buffers now always honors slub
> debug hooks (e.g. object poisoning) and leak checker can detect the
> free operation.
>
> Removal also results in a small speedup (using
> single rule 'iptables -A INPUT -i lo -j AUDIT --type drop'):
>
> super_netperf 4 -H 127.0.0.1 -l 360 -t UDP_RR -- -R 1 -m 64
> Before:
> 294953
> After:
> 298013
>
> (alloc/free no longer serializes on spinlock, allocator can use percpu
> pool).
>
> Signed-off-by: Florian Westphal <fw(a)strlen.de>
> ---
> kernel/audit.c | 53 ++++++++---------------------------------------------
> 1 file changed, 8 insertions(+), 45 deletions(-)
Sorry for the delay, I was hoping to have some time to play around
with this and offer a more meaningful comment ... I've often wondered
about converting audit_buffer, and audit_context for that matter, over
to their own kmem_cache; have you considered that? Or was this
proposed due to simplicity?
Not sure I understand, you could still convert it on top of this.
(Although audit_buffer is just 24 bytes after this patch so it will
come from 32byte kmalloc slab).
I don't think it makes sense to keep this DIY cache on top of slub
cache.