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References: <20210409231842.8840-1-longman@redhat.com> <20210409231842.8840-3-longman@redhat.com>
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From:   Shakeel Butt <shakeelb@google.com>
Date:   Mon, 12 Apr 2021 08:50:51 -0700
Message-ID: <CALvZod5m_J4z0sZrd72yftXhYF9PmtJDfRKDK9WVSMvo7PP6uw@mail.gmail.com>
Subject: Re: [PATCH 2/5] mm/memcg: Introduce obj_cgroup_uncharge_mod_state()
To:     Waiman Long <longman@redhat.com>
Cc:     Johannes Weiner <hannes@cmpxchg.org>,
        Michal Hocko <mhocko@kernel.org>,
        Vladimir Davydov <vdavydov.dev@gmail.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Tejun Heo <tj@kernel.org>, Christoph Lameter <cl@linux.com>,
        Pekka Enberg <penberg@kernel.org>,
        David Rientjes <rientjes@google.com>,
        Joonsoo Kim <iamjoonsoo.kim@lge.com>,
        Vlastimil Babka <vbabka@suse.cz>, Roman Gushchin <guro@fb.com>,
        LKML <linux-kernel@vger.kernel.org>,
        Cgroups <cgroups@vger.kernel.org>, Linux MM <linux-mm@kvack.org>,
        Muchun Song <songmuchun@bytedance.com>,
        Alex Shi <alex.shi@linux.alibaba.com>,
        Chris Down <chris@chrisdown.name>,
        Yafang Shao <laoar.shao@gmail.com>,
        Alexander Duyck <alexander.h.duyck@linux.intel.com>,
        Wei Yang <richard.weiyang@gmail.com>,
        Masayoshi Mizuma <msys.mizuma@gmail.com>
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On Fri, Apr 9, 2021 at 4:19 PM Waiman Long <longman@redhat.com> wrote:
>
> In memcg_slab_free_hook()/pcpu_memcg_free_hook(), obj_cgroup_uncharge()
> is followed by mod_objcg_state()/mod_memcg_state(). Each of these
> function call goes through a separate irq_save/irq_restore cycle. That
> is inefficient.  Introduce a new function obj_cgroup_uncharge_mod_state()
> that combines them with a single irq_save/irq_restore cycle.
>
> Signed-off-by: Waiman Long <longman@redhat.com>

Reviewed-by: Shakeel Butt <shakeelb@google.com>