Date: Mon, 25 Jan 2016 17:15:10 -0800 From: Laura Abbott <labbott@...oraproject.org> To: Christoph Lameter <cl@...ux.com>, Pekka Enberg <penberg@...nel.org>, David Rientjes <rientjes@...gle.com>, Joonsoo Kim <js1304@...il.com>, Andrew Morton <akpm@...ux-foundation.org> Cc: Laura Abbott <labbott@...oraproject.org>, linux-mm@...ck.org, linux-kernel@...r.kernel.org, kernel-hardening@...ts.openwall.com, Kees Cook <keescook@...omium.org> Subject: [RFC][PATCH 0/3] Speed up SLUB poisoning + disable checks Hi, Based on the discussion from the series to add slab sanitization (lkml.kernel.org/g/<1450755641-7856-1-git-send-email-laura@...bott.name>) the existing SLAB_POISON mechanism already covers similar behavior. The performance of SLAB_POISON isn't very good. With hackbench -g 20 -l 1000 on QEMU with one cpu: slub_debug=-: 7.437 slub_debug=P: 15.366 Poisoning memory is certainly going to have a performance impact but there are two major contributors to this slowdown: the fastpath is always disabled when debugging features are enabled and there are lots of expensive consistency checks happening. This series attempts to address both of them. Debugging checks now happen on the fast path. This does involve disabling preemption and interrupts for consistency. This series also introduces a new slab flag to skip consistency checks but let poisoning or possibly tracing to happen. After this series: slub_debug=-: 7.932 slub_debug=PQ: 8.203 slub_debug=P: 10.707 I haven't run this series through a ton of stress tests yet as I was hoping to get some feedback that this approach looks correct. Since I expect this to be the trickiest part of SL*B sanitization, my plan is to focus on getting SLUB speed up merged and then work on the rest of SL*B sanitization. As always, feedback is appreciated. Thanks, Laura Laura Abbott (3): slub: Drop lock at the end of free_debug_processing slub: Don't limit debugging to slow paths slub: Add option to skip consistency checks include/linux/slab.h | 1 + init/Kconfig | 12 +++ mm/slub.c | 214 ++++++++++++++++++++++++++++++++++++++++++++------- 3 files changed, 200 insertions(+), 27 deletions(-) -- 2.5.0
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