From: Joonsoo Kim <iamjoonsoo.kim@lge.com>
To: Laura Abbott <labbott@fedoraproject.org>
Cc: Christoph Lameter <cl@linux.com>,
Pekka Enberg <penberg@kernel.org>,
David Rientjes <rientjes@google.com>,
Andrew Morton <akpm@linux-foundation.org>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
kernel-hardening@lists.openwall.com,
Kees Cook <keescook@chromium.org>
Subject: Re: [RFC][PATCH 0/3] Speed up SLUB poisoning + disable checks
Date: Tue, 26 Jan 2016 16:03:20 +0900 [thread overview]
Message-ID: <20160126070320.GB28254@js1304-P5Q-DELUXE> (raw)
In-Reply-To: <1453770913-32287-1-git-send-email-labbott@fedoraproject.org>
On Mon, Jan 25, 2016 at 05:15:10PM -0800, Laura Abbott wrote:
> Hi,
>
> Based on the discussion from the series to add slab sanitization
> (lkml.kernel.org/g/<1450755641-7856-1-git-send-email-laura@labbott.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:
I doesn't follow up that discussion, but, I think that reusing
SLAB_POISON for slab sanitization needs more changes. I assume that
completeness and performance is matter for slab sanitization.
1) SLAB_POISON isn't applied to specific kmem_cache which has
constructor or SLAB_DESTROY_BY_RCU flag. For debug, it's not necessary
to be applied, but, for slab sanitization, it is better to apply it to
all caches.
2) SLAB_POISON makes object size bigger so natural alignment will be
broken. For example, kmalloc(256) cache's size is 256 in normal
case but it would be 264 when SLAB_POISON is enabled. This causes
memory waste.
In fact, I'd prefer not reusing SLAB_POISON. It would make thing
simpler. But, it's up to Christoph.
Thanks.
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next prev parent reply other threads:[~2016-01-26 7:03 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-26 1:15 Laura Abbott
2016-01-26 1:15 ` [RFC][PATCH 1/3] slub: Drop lock at the end of free_debug_processing Laura Abbott
2016-01-26 16:19 ` Christoph Lameter
2016-01-26 1:15 ` [RFC][PATCH 2/3] slub: Don't limit debugging to slow paths Laura Abbott
2016-01-26 8:48 ` Paul Bolle
2016-01-26 1:15 ` [PATCH 3/3] slub: Add option to skip consistency checks Laura Abbott
2016-01-26 15:00 ` Christoph Lameter
2016-01-26 7:03 ` Joonsoo Kim [this message]
2016-01-26 15:01 ` [RFC][PATCH 0/3] Speed up SLUB poisoning + disable checks Christoph Lameter
2016-01-26 15:21 ` Joonsoo Kim
2016-02-03 18:46 ` Laura Abbott
2016-02-03 21:06 ` Kees Cook
2016-02-03 21:35 ` Laura Abbott
2016-02-03 23:02 ` Christoph Lameter
2016-02-04 0:46 ` Laura Abbott
2016-02-04 3:23 ` Christoph Lameter
2016-01-26 14:57 ` Christoph Lameter
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