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Re: [PATCH 2/4] mm: memcontrol: reign in the CONFIG space madness

From Johannes Weiner <hannes@cmpxchg.org>
Newsgroups linux.kernel
Subject Re: [PATCH 2/4] mm: memcontrol: reign in the CONFIG space madness
Date 2015-12-12 18:30 +0100
Message-ID <qEW9A-542-7@gated-at.bofh.it> (permalink)
References <qEC1b-q7-1@gated-at.bofh.it> <qEC1c-q7-9@gated-at.bofh.it> <qEVnb-4xa-13@gated-at.bofh.it>
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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 <hannes@cmpxchg.org>
> 
> Acked-by: Vladimir Davydov <vdavydov@virtuozzo.com>
> 
> > @@ -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(). :-)

From 94a14b7b0f7ed5b5ac88ca285a7e8ec3215ea59c Mon Sep 17 00:00:00 2001
From: Johannes Weiner <hannes@cmpxchg.org>
Date: Sat, 12 Dec 2015 12:14:31 -0500
Subject: [PATCH] net: drop tcp_memcontrol.c fix

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
---
 mm/memcontrol.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 5cf7fd2..a4ce8d3 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -4386,8 +4386,6 @@ static void mem_cgroup_css_free(struct cgroup_subsys_state *css)
 		static_branch_dec(&memcg_sockets_enabled_key);
 #endif
 
-	memcg_free_kmem(memcg);
-
 	__mem_cgroup_free(memcg);
 }
 
-- 
2.6.4
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Thread

[PATCH 1/4] net: tcp_memcontrol: simplify linkage between socket and page counter fix Johannes Weiner <hannes@cmpxchg.org> - 2015-12-11 21:00 +0100
  [PATCH 4/4] mm: memcontrol: clean up alloc, online, offline, free functions Johannes Weiner <hannes@cmpxchg.org> - 2015-12-11 21:00 +0100
    Re: [PATCH 4/4] mm: memcontrol: clean up alloc, online, offline,  free functions Vladimir Davydov <vdavydov@virtuozzo.com> - 2015-12-14 18:20 +0100
      Re: [PATCH 4/4] mm: memcontrol: clean up alloc, online, offline,  free functions Johannes Weiner <hannes@cmpxchg.org> - 2015-12-15 20:40 +0100
        Re: [PATCH 4/4] mm: memcontrol: clean up alloc, online, offline,  free functions Vladimir Davydov <vdavydov@virtuozzo.com> - 2015-12-16 13:20 +0100
          Re: [PATCH 4/4] mm: memcontrol: clean up alloc, online, offline,  free functions Johannes Weiner <hannes@cmpxchg.org> - 2015-12-17 01:50 +0100
  [PATCH 2/4] mm: memcontrol: reign in the CONFIG space madness Johannes Weiner <hannes@cmpxchg.org> - 2015-12-11 21:00 +0100
    Re: [PATCH 2/4] mm: memcontrol: reign in the CONFIG space madness Vladimir Davydov <vdavydov@virtuozzo.com> - 2015-12-12 17:40 +0100
      Re: [PATCH 2/4] mm: memcontrol: reign in the CONFIG space madness Johannes Weiner <hannes@cmpxchg.org> - 2015-12-12 18:30 +0100
        Re: [PATCH 2/4] mm: memcontrol: reign in the CONFIG space madness Andrew Morton <akpm@linux-foundation.org> - 2015-12-23 00:20 +0100
          Re: [PATCH 2/4] mm: memcontrol: reign in the CONFIG space madness Andrew Morton <akpm@linux-foundation.org> - 2015-12-23 00:20 +0100
            Re: [PATCH 2/4] mm: memcontrol: reign in the CONFIG space madness Johannes Weiner <hannes@cmpxchg.org> - 2015-12-23 00:40 +0100
  [PATCH 3/4] mm: memcontrol: flatten struct cg_proto Johannes Weiner <hannes@cmpxchg.org> - 2015-12-11 21:00 +0100
    Re: [PATCH 3/4] mm: memcontrol: flatten struct cg_proto Vladimir Davydov <vdavydov@virtuozzo.com> - 2015-12-12 17:40 +0100

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