Date: Tue, 26 Jan 2016 16:03:20 +0900 From: Joonsoo Kim <iamjoonsoo.kim@....com> To: Laura Abbott <labbott@...oraproject.org> Cc: Christoph Lameter <cl@...ux.com>, Pekka Enberg <penberg@...nel.org>, David Rientjes <rientjes@...gle.com>, Andrew Morton <akpm@...ux-foundation.org>, linux-mm@...ck.org, linux-kernel@...r.kernel.org, kernel-hardening@...ts.openwall.com, Kees Cook <keescook@...omium.org> Subject: Re: [RFC][PATCH 0/3] Speed up SLUB poisoning + disable checks 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@...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: 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.
Powered by blists - more mailing lists
Confused about mailing lists and their use? Read about mailing lists on Wikipedia and check out these guidelines on proper formatting of your messages.