Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S642486AbdEAClQ (ORCPT ); Sun, 30 Apr 2017 22:41:16 -0400 Received: from bombadil.infradead.org ([65.50.211.133]:51665 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1165321AbdEAClI (ORCPT ); Sun, 30 Apr 2017 22:41:08 -0400 Date: Sun, 30 Apr 2017 19:41:03 -0700 From: Matthew Wilcox To: Wei Yang Cc: cl@linux.com, penberg@kernel.org, rientjes@google.com, iamjoonsoo.kim@lge.com, akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/3] mm/slub: wrap cpu_slab->partial in CONFIG_SLUB_CPU_PARTIAL Message-ID: <20170501024103.GI27790@bombadil.infradead.org> References: <20170430113152.6590-1-richard.weiyang@gmail.com> <20170430113152.6590-3-richard.weiyang@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170430113152.6590-3-richard.weiyang@gmail.com> User-Agent: Mutt/1.8.0 (2017-02-23) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1571 Lines: 56 On Sun, Apr 30, 2017 at 07:31:51PM +0800, Wei Yang wrote: > @@ -2302,7 +2302,11 @@ static bool has_cpu_slab(int cpu, void *info) > struct kmem_cache *s = info; > struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu); > > - return c->page || c->partial; > + return c->page > +#ifdef CONFIG_SLUB_CPU_PARTIAL > + || c->partial > +#endif > + ; > } No. No way. This is disgusting. The right way to do this is to create an accessor like this: #ifdef CONFIG_SLUB_CPU_PARTIAL #define slub_cpu_partial(c) ((c)->partial) #else #define slub_cpu_partial(c) 0 #endif And then the above becomes: - return c->page || c->partial; + return c->page || slub_cpu_partial(c); All the other ifdefs go away, apart from these two: > @@ -4980,6 +4990,7 @@ static ssize_t objects_partial_show(struct kmem_cache *s, char *buf) > } > SLAB_ATTR_RO(objects_partial); > > +#ifdef CONFIG_SLUB_CPU_PARTIAL > static ssize_t slabs_cpu_partial_show(struct kmem_cache *s, char *buf) > { > int objects = 0; > @@ -5010,6 +5021,7 @@ static ssize_t slabs_cpu_partial_show(struct kmem_cache *s, char *buf) > return len + sprintf(buf + len, "\n"); > } > SLAB_ATTR_RO(slabs_cpu_partial); > +#endif > > static ssize_t reclaim_account_show(struct kmem_cache *s, char *buf) > { > @@ -5364,7 +5376,9 @@ static struct attribute *slab_attrs[] = { > &destroy_by_rcu_attr.attr, > &shrink_attr.attr, > &reserved_attr.attr, > +#ifdef CONFIG_SLUB_CPU_PARTIAL > &slabs_cpu_partial_attr.attr, > +#endif > #ifdef CONFIG_SLUB_DEBUG > &total_objects_attr.attr, > &slabs_attr.attr,