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Mon, 28 Feb 2022 04:23:33 -0800 (PST) From: Muchun Song To: willy@infradead.org, akpm@linux-foundation.org, hannes@cmpxchg.org, mhocko@kernel.org, vdavydov.dev@gmail.com, shakeelb@google.com, roman.gushchin@linux.dev, shy828301@gmail.com, alexs@kernel.org, richard.weiyang@gmail.com, david@fromorbit.com, trond.myklebust@hammerspace.com, anna.schumaker@netapp.com, jaegeuk@kernel.org, chao@kernel.org, kari.argillander@gmail.com, vbabka@suse.cz Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-nfs@vger.kernel.org, zhengqi.arch@bytedance.com, duanxiongchun@bytedance.com, fam.zheng@bytedance.com, smuchun@gmail.com, Muchun Song Subject: [PATCH v6 09/16] mm: memcontrol: move memcg_online_kmem() to mem_cgroup_css_online() Date: Mon, 28 Feb 2022 20:21:19 +0800 Message-Id: <20220228122126.37293-10-songmuchun@bytedance.com> X-Mailer: git-send-email 2.32.0 (Apple Git-132) In-Reply-To: <20220228122126.37293-1-songmuchun@bytedance.com> References: <20220228122126.37293-1-songmuchun@bytedance.com> MIME-Version: 1.0 X-Rspam-User: X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: C1AE340005 X-Stat-Signature: zq3df1jfau65e9hu4f6ges8718oidfbw Authentication-Results: imf27.hostedemail.com; dkim=pass header.d=bytedance-com.20210112.gappssmtp.com header.s=20210112 header.b=jNIurO4J; dmarc=pass (policy=none) header.from=bytedance.com; spf=pass (imf27.hostedemail.com: domain of songmuchun@bytedance.com designates 209.85.215.180 as permitted sender) smtp.mailfrom=songmuchun@bytedance.com X-HE-Tag: 1646051014-87336 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: It will simplify the code if moving memcg_online_kmem() to mem_cgroup_css_online() and do not need to set ->kmemcg_id to -1 to indicate the memcg is offline. In the next patch, ->kmemcg_id will be used to sync list lru reparenting which requires not to change ->kmemcg_id. Signed-off-by: Muchun Song Acked-by: Roman Gushchin --- mm/memcontrol.c | 37 ++++++++++++++++--------------------- 1 file changed, 16 insertions(+), 21 deletions(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index ffc5f0798de1..5bdf5184681c 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -3616,7 +3616,8 @@ static int memcg_online_kmem(struct mem_cgroup *memcg) if (cgroup_memory_nokmem) return 0; - BUG_ON(memcg->kmemcg_id >= 0); + if (unlikely(mem_cgroup_is_root(memcg))) + return 0; memcg_id = memcg_alloc_cache_id(); if (memcg_id < 0) @@ -3642,7 +3643,10 @@ static void memcg_offline_kmem(struct mem_cgroup *memcg) struct mem_cgroup *parent; int kmemcg_id; - if (memcg->kmemcg_id == -1) + if (cgroup_memory_nokmem) + return; + + if (unlikely(mem_cgroup_is_root(memcg))) return; parent = parent_mem_cgroup(memcg); @@ -3652,7 +3656,6 @@ static void memcg_offline_kmem(struct mem_cgroup *memcg) memcg_reparent_objcgs(memcg, parent); kmemcg_id = memcg->kmemcg_id; - BUG_ON(kmemcg_id < 0); /* * After we have finished memcg_reparent_objcgs(), all list_lrus @@ -3663,7 +3666,6 @@ static void memcg_offline_kmem(struct mem_cgroup *memcg) memcg_drain_all_list_lrus(kmemcg_id, parent); memcg_free_cache_id(kmemcg_id); - memcg->kmemcg_id = -1; } #else static int memcg_online_kmem(struct mem_cgroup *memcg) @@ -5178,7 +5180,6 @@ mem_cgroup_css_alloc(struct cgroup_subsys_state *parent_css) { struct mem_cgroup *parent = mem_cgroup_from_css(parent_css); struct mem_cgroup *memcg, *old_memcg; - long error = -ENOMEM; old_memcg = set_active_memcg(parent); memcg = mem_cgroup_alloc(); @@ -5207,34 +5208,26 @@ mem_cgroup_css_alloc(struct cgroup_subsys_state *parent_css) return &memcg->css; } - /* The following stuff does not apply to the root */ - error = memcg_online_kmem(memcg); - if (error) - goto fail; - if (cgroup_subsys_on_dfl(memory_cgrp_subsys) && !cgroup_memory_nosocket) static_branch_inc(&memcg_sockets_enabled_key); return &memcg->css; -fail: - mem_cgroup_id_remove(memcg); - mem_cgroup_free(memcg); - return ERR_PTR(error); } static int mem_cgroup_css_online(struct cgroup_subsys_state *css) { struct mem_cgroup *memcg = mem_cgroup_from_css(css); + if (memcg_online_kmem(memcg)) + goto remove_id; + /* * A memcg must be visible for expand_shrinker_info() * by the time the maps are allocated. So, we allocate maps * here, when for_each_mem_cgroup() can't skip it. */ - if (alloc_shrinker_info(memcg)) { - mem_cgroup_id_remove(memcg); - return -ENOMEM; - } + if (alloc_shrinker_info(memcg)) + goto offline_kmem; /* Online state pins memcg ID, memcg ID pins CSS */ refcount_set(&memcg->id.ref, 1); @@ -5244,6 +5237,11 @@ static int mem_cgroup_css_online(struct cgroup_subsys_state *css) queue_delayed_work(system_unbound_wq, &stats_flush_dwork, 2UL*HZ); return 0; +offline_kmem: + memcg_offline_kmem(memcg); +remove_id: + mem_cgroup_id_remove(memcg); + return -ENOMEM; } static void mem_cgroup_css_offline(struct cgroup_subsys_state *css) @@ -5301,9 +5299,6 @@ static void mem_cgroup_css_free(struct cgroup_subsys_state *css) cancel_work_sync(&memcg->high_work); mem_cgroup_remove_from_trees(memcg); free_shrinker_info(memcg); - - /* Need to offline kmem if online_css() fails */ - memcg_offline_kmem(memcg); mem_cgroup_free(memcg); }