From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Morton Subject: Re: [PATCH 2/4] mm: memcontrol: reign in the CONFIG space madness Date: Tue, 22 Dec 2015 15:11:38 -0800 Message-ID: <20151222151138.0c35816e53b0f0ad940568bb@linux-foundation.org> References: <1449863653-6546-1-git-send-email-hannes@cmpxchg.org> <1449863653-6546-2-git-send-email-hannes@cmpxchg.org> <20151212163332.GC28521@esperanza> <20151212172057.GA7997@cmpxchg.org> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20151212172057.GA7997-druUgvl0LCNAfugRpC6u6w@public.gmane.org> Sender: cgroups-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: Content-Type: text/plain; charset="us-ascii" To: Johannes Weiner Cc: Vladimir Davydov , Michal Hocko , linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org, cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, kernel-team-b10kYP2dOMg@public.gmane.org On Sat, 12 Dec 2015 12:20:57 -0500 Johannes Weiner wrote: > On Sat, Dec 12, 2015 at 07:33:32PM +0300, Vladimir Davydov wrote: > > On Fri, Dec 11, 2015 at 02:54:11PM -0500, Johannes Weiner wrote: > > > What CONFIG_INET and CONFIG_LEGACY_KMEM guard inside the memory > > > controller code is insignificant, having these conditionals is not > > > worth the complication and fragility that comes with them. > > > > > > Signed-off-by: Johannes Weiner > > > > Acked-by: Vladimir Davydov > > > > > @@ -4374,17 +4342,11 @@ static void mem_cgroup_css_free(struct cgroup_subsys_state *css) > > > { > > > struct mem_cgroup *memcg = mem_cgroup_from_css(css); > > > > > > -#ifdef CONFIG_INET > > > if (cgroup_subsys_on_dfl(memory_cgrp_subsys) && !cgroup_memory_nosocket) > > > static_branch_dec(&memcg_sockets_enabled_key); > > > -#endif > > > - > > > - memcg_free_kmem(memcg); > > > > I wonder where the second call to memcg_free_kmem comes from. Luckily, > > it couldn't result in a breakage. And now it's removed. > > Lol, I had to double check my trees to see what's going on as I don't > remember this being part of the patch. But it looks like the double > free came from the "net: drop tcp_memcontrol.c" patch and I must have > removed it again during conflict resolution when rebasing this patch > on top of yours. I must have thought git's auto-merge added it. > > However, this causes an underflow of the kmem static branch, so we > will have to fix this directly in "net: drop tcp_memcontrol.c". > > Andrew, could you please pick this up? However, it's important to also > then remove the hunk above from THIS patch, the one that deletes the > excessive memcg_free_kmem(). We need exactly one memcg_free_kmem() in > mem_cgroup_css_free(). :-) So you want to retain mm-memcontrol-reign-in-the-config-space-madness.patch's removal of the ifdef CONFIG_INET? What I have is Against net-drop-tcp_memcontrolc.patch: --- a/mm/memcontrol.c~net-drop-tcp_memcontrolc-fix +++ a/mm/memcontrol.c @@ -4421,8 +4421,6 @@ static void mem_cgroup_css_free(struct c static_branch_dec(&memcg_sockets_enabled_key); #endif - memcg_free_kmem(memcg); - __mem_cgroup_free(memcg); } and against mm-memcontrol-reign-in-the-config-space-madness.patch: --- a/mm/memcontrol.c~mm-memcontrol-reign-in-the-config-space-madness-fix +++ a/mm/memcontrol.c @@ -4380,6 +4380,8 @@ static void mem_cgroup_css_free(struct c if (cgroup_subsys_on_dfl(memory_cgrp_subsys) && !cgroup_memory_nosocket) static_branch_dec(&memcg_sockets_enabled_key); + memcg_free_kmem(memcg); + if (memcg->tcp_mem.active) static_branch_dec(&memcg_sockets_enabled_key); Producing static void mem_cgroup_css_free(struct cgroup_subsys_state *css) { struct mem_cgroup *memcg = mem_cgroup_from_css(css); if (cgroup_subsys_on_dfl(memory_cgrp_subsys) && !cgroup_memory_nosocket) static_branch_dec(&memcg_sockets_enabled_key); memcg_free_kmem(memcg); if (memcg->tcp_mem.active) static_branch_dec(&memcg_sockets_enabled_key); __mem_cgroup_free(memcg); } And I did s/reign/rein/;)