From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755752AbcLABr6 (ORCPT ); Wed, 30 Nov 2016 20:47:58 -0500 Received: from Chamillionaire.breakpoint.cc ([146.0.238.67]:50230 "EHLO Chamillionaire.breakpoint.cc" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753217AbcLABr5 (ORCPT ); Wed, 30 Nov 2016 20:47:57 -0500 Date: Thu, 1 Dec 2016 02:44:55 +0100 From: Florian Westphal To: Paul Moore Cc: Florian Westphal , linux-kernel@vger.kernel.org, linux-audit@redhat.com, Eric Paris Subject: Re: [PATCH] audit: remove the audit freelist Message-ID: <20161201014455.GD26507@breakpoint.cc> References: <1479215774-29810-1-git-send-email-fw@strlen.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Paul Moore wrote: > On Tue, Nov 15, 2016 at 8:16 AM, Florian Westphal 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 > > --- > > 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.