From mboxrd@z Thu Jan 1 00:00:00 1970 From: Johannes Weiner Subject: Re: [PATCH] mm: memcontrol: MEMCG no longer works with SLOB Date: Wed, 9 Dec 2015 15:01:07 -0500 Message-ID: <20151209200107.GA17409@cmpxchg.org> References: <1449588624-9220-1-git-send-email-hannes@cmpxchg.org> <2564892.qO1q7YJ6Nb@wuerfel> <1558902.EBTjGmY9S2@wuerfel> Mime-Version: 1.0 Return-path: Content-Disposition: inline In-Reply-To: <1558902.EBTjGmY9S2@wuerfel> Sender: cgroups-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Arnd Bergmann Cc: Andrew Morton , linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org, netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Vladimir Davydov On Wed, Dec 09, 2015 at 05:32:39PM +0100, Arnd Bergmann wrote: > The change to move the kmem accounting into the normal memcg > code means we can no longer use memcg with slob, which lacks > the memcg_params member in its struct kmem_cache: > > ../mm/slab.h: In function 'is_root_cache': > ../mm/slab.h:187:10: error: 'struct kmem_cache' has no member named 'memcg_params' > > This enforces the new dependency in Kconfig. Alternatively, > we could change the slob code to allow using MEMCG. I'm curious, was this a random config or do you actually use CONFIG_SLOB && CONFIG_MEMCG? Excluding CONFIG_MEMCG completely for slob seems harsh, but I would prefer not littering the source with #if defined(CONFIG_MEMCG) && (defined(CONFIG_SLAB) || defined(CONFIG_SLUB)) or #if defined(CONFIG_MEMCG) && !defined(CONFIG_SLOB) for such a special case. The #ifdefs are already out of hand in there. Vladimir, what would you think of simply doing this? diff --git a/mm/slab.h b/mm/slab.h index 5adec08..0b3ec4b 100644 --- a/mm/slab.h +++ b/mm/slab.h @@ -25,6 +25,9 @@ struct kmem_cache { int refcount; /* Use counter */ void (*ctor)(void *); /* Called on object slot creation */ struct list_head list; /* List of all slab caches on the system */ +#ifdef CONFIG_MEMCG + struct memcg_cache_params memcg_params; +#endif }; #endif /* CONFIG_SLOB */