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From: Jesper Dangaard Brouer <brouer@redhat.com>
To: Christoph Lameter <cl@linux.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	linux-mm@kvack.org, Alexander Duyck <alexander.duyck@gmail.com>,
	Pekka Enberg <penberg@kernel.org>,
	netdev@vger.kernel.org, Joonsoo Kim <iamjoonsoo.kim@lge.com>,
	David Rientjes <rientjes@google.com>,
	brouer@redhat.com
Subject: Re: [MM PATCH V4.1 5/6] slub: support for bulk free with SLUB freelists
Date: Fri, 2 Oct 2015 12:40:01 +0200	[thread overview]
Message-ID: <20151002124001.2c1d9d7d@redhat.com> (raw)
In-Reply-To: <alpine.DEB.2.20.1510020508580.2991@east.gentwo.org>

On Fri, 2 Oct 2015 05:10:02 -0500 (CDT)
Christoph Lameter <cl@linux.com> wrote:

> On Fri, 2 Oct 2015, Jesper Dangaard Brouer wrote:
> 
> > Thus, I need introducing new code like this patch and at the same time
> > have to reduce the number of instruction-cache misses/usage.  In this
> > case we solve the problem by kmem_cache_free_bulk() not getting called
> > too often. Thus, +17 bytes will hopefully not matter too much... but on
> > the other hand we sort-of know that calling kmem_cache_free_bulk() will
> > cause icache misses.
> 
> Can we just drop the WARN/BUG here? Nothing untoward happens if size == 0
> right?

I think we crash if size == 0, as we deref p[--size] in build_detached_freelist().


(aside note: The code do handles if pointers in the p array are NULL)
-- 
Best regards,
  Jesper Dangaard Brouer
  MSc.CS, Principal Kernel Engineer at Red Hat
  Author of http://www.iptv-analyzer.org
  LinkedIn: http://www.linkedin.com/in/brouer

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  reply	other threads:[~2015-10-02 10:40 UTC|newest]

Thread overview: 50+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-09-28 12:26 [PATCH 0/7] Further optimizing SLAB/SLUB bulking Jesper Dangaard Brouer
2015-09-28 12:26 ` [PATCH 1/7] slub: create new ___slab_alloc function that can be called with irqs disabled Jesper Dangaard Brouer
2015-09-28 12:26 ` [PATCH 2/7] slub: Avoid irqoff/on in bulk allocation Jesper Dangaard Brouer
2015-09-28 12:26 ` [PATCH 3/7] slub: mark the dangling ifdef #else of CONFIG_SLUB_DEBUG Jesper Dangaard Brouer
2015-09-28 13:49   ` Christoph Lameter
2015-09-28 12:26 ` [PATCH 4/7] slab: implement bulking for SLAB allocator Jesper Dangaard Brouer
2015-09-28 15:11   ` Christoph Lameter
2015-09-28 12:26 ` [PATCH 5/7] slub: support for bulk free with SLUB freelists Jesper Dangaard Brouer
2015-09-28 15:16   ` Christoph Lameter
2015-09-28 15:51     ` Jesper Dangaard Brouer
2015-09-28 16:28       ` Christoph Lameter
2015-09-29  7:32         ` Jesper Dangaard Brouer
2015-09-28 16:30       ` Christoph Lameter
2015-09-29  7:12         ` Jesper Dangaard Brouer
2015-09-28 12:26 ` [PATCH 6/7] slub: optimize bulk slowpath free by detached freelist Jesper Dangaard Brouer
2015-09-28 15:22   ` Christoph Lameter
2015-09-28 12:26 ` [PATCH 7/7] slub: do prefetching in kmem_cache_alloc_bulk() Jesper Dangaard Brouer
2015-09-28 14:53   ` Alexander Duyck
2015-09-28 15:59     ` Jesper Dangaard Brouer
2015-09-29 15:46 ` [MM PATCH V4 0/6] Further optimizing SLAB/SLUB bulking Jesper Dangaard Brouer
2015-09-29 15:47   ` [MM PATCH V4 1/6] slub: create new ___slab_alloc function that can be called with irqs disabled Jesper Dangaard Brouer
2015-09-29 15:47   ` [MM PATCH V4 2/6] slub: Avoid irqoff/on in bulk allocation Jesper Dangaard Brouer
2015-09-29 15:47   ` [MM PATCH V4 3/6] slub: mark the dangling ifdef #else of CONFIG_SLUB_DEBUG Jesper Dangaard Brouer
2015-09-29 15:48   ` [MM PATCH V4 4/6] slab: implement bulking for SLAB allocator Jesper Dangaard Brouer
2015-09-29 15:48   ` [MM PATCH V4 5/6] slub: support for bulk free with SLUB freelists Jesper Dangaard Brouer
2015-09-29 16:38     ` Alexander Duyck
2015-09-29 17:00       ` Jesper Dangaard Brouer
2015-09-29 17:20         ` Alexander Duyck
2015-09-29 18:16           ` Jesper Dangaard Brouer
2015-09-30 11:44       ` [MM PATCH V4.1 " Jesper Dangaard Brouer
2015-09-30 16:03         ` Christoph Lameter
2015-10-01 22:10         ` Andrew Morton
2015-10-02  9:41           ` Jesper Dangaard Brouer
2015-10-02 10:10             ` Christoph Lameter
2015-10-02 10:40               ` Jesper Dangaard Brouer [this message]
2015-10-02 13:40             ` Jesper Dangaard Brouer
2015-10-02 21:50               ` Andrew Morton
2015-10-05 19:26                 ` Jesper Dangaard Brouer
2015-10-05 21:20                   ` Andi Kleen
2015-10-05 23:07                     ` Jesper Dangaard Brouer
2015-10-07 12:31                       ` Jesper Dangaard Brouer
2015-10-07 13:36                         ` Arnaldo Carvalho de Melo
2015-10-07 15:44                           ` Andi Kleen
2015-10-07 16:06                         ` Andi Kleen
2015-10-05 23:53                   ` Jesper Dangaard Brouer
2015-10-07 10:39                   ` Jesper Dangaard Brouer
2015-09-29 15:48   ` [MM PATCH V4 6/6] slub: optimize bulk slowpath free by detached freelist Jesper Dangaard Brouer
2015-10-14  5:15     ` Joonsoo Kim
2015-10-21  7:57       ` Jesper Dangaard Brouer
2015-11-05  5:09         ` Joonsoo Kim

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