Re: [PATCH] audit: remove the audit freelist

On Wed, Nov 30, 2016 at 8:44 PM, Florian Westphal <fw(a)strlen.de&gt; wrote: > Paul Moore <paul(a)paul-moore.com&gt; wrote: >> On Tue, Nov 15, 2016 at 8:16 AM, Florian Westphal <fw(a)strlen.de&gt; 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&gt; >> > --- >> > 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'm not arguing against this patch, partly just musing out loud, partly just seeing if you had experimented with creating a audit_buffer specific kmem_cache (I'm guessing the answer here is "no"). If we do convert to a kmem_cache this patch would be the obvious first step.