From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1792832265; b=fNCnySXp/jqpOVr5knMLI5S8iwEk2jX15nUfOgggJ8J8VcfSjuG2sovv/1frpYhM5nXa aqfdOcRg+j8+D5IB33axwjsjIqe3F+K+dZ8+QxaAFNti9f1DLnoxynWbXHnd7MND0SEat CaTSl+9gtPbOipplv/kDxiGEDkPBwlMwSM/hPshnQ44V2HFePSCtb4urGK4sTetus128J L3L+Mi5a5S0ELjtDJGwaYKCkdiUReo/o/6Tdob7+eIp3fKWbECUquQ2VyC2PX2kS26AH+ N2ZL8Q0CqTQp6khJlvKy1YnxZLPsuLt08PZH02L+WuT0XzWXlauLMqdV1r06BhlmcVg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792832265; h=Received:DKIM-Signature:Date:To:From:Subject:Message-Id; bh=NHEISGyoal2V37RMrwy1zxIB2PNTj2QHkjcn0dm95IY=; b=zO5AXXTljeUu1Kn3VprOMsiK8yLZsM3Ht/I6ozUyKxj4q6Tirq+YYXctjK4bz520FABq YTnK3rRQfIIIlC7XaM504+ia58Z3GfPq8kd1ojHKL31wSYloTsAMfW3p+wlztWPJJ1iQZ D1Pwx4miavWgoowTY8pue40ZJ0Y8mj6VmeKAP2kLto0tIcKEV+ePGUu8+NNvSGgQ3sN8c nt2uql5WQSxEHkEjltXdWIADPF2IYLJVOZis+NJMlIdU1nY9elFzhW+dzVViK7AYfm9b+ L8BcPtULpez1aWiLf0hk/M57dcBv1WPj1AU8Pd1Ofn3I/MxE8TQxBQtMbSkp+vdiU+Q== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linux-foundation.org header.i=@linux-foundation.org header.a=rsa-sha256 header.s=korg header.b=zyu5P39L; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DB392606A31A for ; Sat, 24 Oct 2026 08:57:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linux-foundation.org header.i=@linux-foundation.org header.a=rsa-sha256 header.s=korg header.b=zyu5P39L Received: by smtp.kernel.org (Postfix) with ESMTPSA id A908A1F01829; Sat, 24 Oct 2026 08:57:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=korg; t=1792832264; bh=NHEISGyoal2V37RMrwy1zxIB2PNTj2QHkjcn0dm95IY=; h=Date:To:From:Subject; b=zyu5P39LSjA2CbdpJ8mDKJaRcy3OAkQM8qc2BzHQk1FCYD5g1eKe2KEUH0GsR7D3x kGg/ydsU7jEkY2nQFTLLZNld/Y0HVCdSEpgW6B0dMd4LsAiPMnjgqJmBa2b7SltFKE 8LMGqsAds1rTjWlea01b1btor1ATFh+WVrCSC56E= Date: Sat, 24 Oct 2026 01:57:44 -0700 To: mm-commits@vger.kernel.org,yuanchu@google.com,weixugc@google.com,shakeel.butt@linux.dev,roman.gushchin@linux.dev,qi.zheng@linux.dev,muchun.song@linux.dev,mhocko@kernel.org,ljs@kernel.org,kasong@tencent.com,hannes@cmpxchg.org,david@kernel.org,david@fromorbit.com,bfguo@icloud.com,baohua@kernel.org,axelrasmussen@google.com,bingfangguo@tencent.com,akpm@linux-foundation.org From: Andrew Morton Subject: [merged mm-stable] memcg-manipulate-memcg-private-id-references-by-id.patch removed from -mm tree Message-Id: <20261024085744.A908A1F01829@smtp.kernel.org> X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list The quilt patch titled Subject: memcg: manipulate memcg private ID references by ID has been removed from the -mm tree. Its filename was memcg-manipulate-memcg-private-id-references-by-id.patch This patch was dropped because it was merged into the mm-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: Bingfang Guo Subject: memcg: manipulate memcg private ID references by ID Date: Mon, 21 Sep 2026 14:16:26 +0800 This is a preparatory work for moving memcgid from memcg to objcg. Swap entries retain a private ID rather than a memcg pointer. Once private ID references are moved to objcgs, the ID can also outlive the memcg to which it was originally assigned. So it's better to make the get and put functions accept the ID itself instead of the memcg. Rename mem_cgroup_private_id_get_online() to mem_cgroup_private_id_get(), and make it return the ID only. If the memcg is already dying, the dying memcg will still be used for charging and stats accounting in v2 swap charging path. But they are hierarchical and will be reparented after offlining so it doesn't matter. Make mem_cgroup_private_id_put() take the ID and resolve the reference holder internally. Convert swap uncharge and charge rollback to release the reference using that ID. This introduces an extra xarray lookup for now, which will be removed in the final patch. Separate the online-state reference release into mem_cgroup_private_id_kill(). The offline path already has the memcg pointer and can call the underlying put helper directly. Link: https://lore.kernel.org/20260921-bingfangguo-memcgid-rework-v2-3-6c0637dc0edb@tencent.com Signed-off-by: Bingfang Guo Signed-off-by: Andrew Morton Acked-by: Muchun Song Cc: Johannes Weiner Cc: Michal Hocko Cc: Roman Gushchin Cc: Shakeel Butt Cc: Dave Chinner Cc: Qi Zheng Cc: Kairui Song Cc: Barry Song Cc: Axel Rasmussen Cc: Yuanchu Xie Cc: Wei Xu Cc: David Hildenbrand Cc: Lorenzo Stoakes Cc: Bingfang Guo --- mm/memcontrol-v1.c | 7 +++---- mm/memcontrol-v1.h | 3 +-- mm/memcontrol.c | 32 +++++++++++++++++++++++--------- 3 files changed, 27 insertions(+), 15 deletions(-) --- a/mm/memcontrol.c~memcg-manipulate-memcg-private-id-references-by-id +++ a/mm/memcontrol.c @@ -4082,7 +4082,7 @@ static void mem_cgroup_private_id_remove } } -static inline void mem_cgroup_private_id_put(struct mem_cgroup *memcg, unsigned int n) +static void __mem_cgroup_private_id_put(struct mem_cgroup *memcg, unsigned int n) { if (refcount_sub_and_test(n, &memcg->private_id_ref)) { mem_cgroup_private_id_remove(memcg); @@ -4092,7 +4092,22 @@ static inline void mem_cgroup_private_id } } -struct mem_cgroup *mem_cgroup_private_id_get_online(struct mem_cgroup *memcg, unsigned int n) +static inline void mem_cgroup_private_id_put(unsigned short id, unsigned int n) +{ + struct mem_cgroup *memcg; + + lockdep_assert_in_rcu_read_lock(); + + memcg = mem_cgroup_from_private_id(id); + __mem_cgroup_private_id_put(memcg, n); +} + +static void mem_cgroup_private_id_kill(struct mem_cgroup *memcg) +{ + __mem_cgroup_private_id_put(memcg, 1); +} + +unsigned short mem_cgroup_private_id_get(struct mem_cgroup *memcg, unsigned int n) { while (!refcount_add_not_zero(n, &memcg->private_id_ref)) { /* @@ -4105,7 +4120,8 @@ struct mem_cgroup *mem_cgroup_private_id } memcg = parent_mem_cgroup(memcg); } - return memcg; + + return mem_cgroup_private_id(memcg); } /** @@ -4430,7 +4446,7 @@ static void mem_cgroup_css_offline(struc drain_all_stock(memcg); - mem_cgroup_private_id_put(memcg, 1); + mem_cgroup_private_id_kill(memcg); } static void mem_cgroup_css_released(struct cgroup_subsys_state *css) @@ -5971,15 +5987,13 @@ int __mem_cgroup_try_charge_swap(struct return 0; } - memcg = mem_cgroup_private_id_get_online(memcg, nr_pages); - /* memcg is pined by memcg ID. */ - private_id = mem_cgroup_private_id(memcg); + private_id = mem_cgroup_private_id_get(memcg, nr_pages); if (!mem_cgroup_private_id_is_root(private_id) && !page_counter_try_charge(&memcg->swap, nr_pages, &counter)) { memcg_memory_event(memcg, MEMCG_SWAP_MAX); memcg_memory_event(memcg, MEMCG_SWAP_FAIL); - mem_cgroup_private_id_put(memcg, nr_pages); + mem_cgroup_private_id_put(private_id, nr_pages); return -ENOMEM; } mod_memcg_state(memcg, MEMCG_SWAP, nr_pages); @@ -6011,7 +6025,7 @@ void __mem_cgroup_uncharge_swap(unsigned page_counter_uncharge(&memcg->swap, nr_pages); } mod_memcg_state(memcg, MEMCG_SWAP, -nr_pages); - mem_cgroup_private_id_put(memcg, nr_pages); + mem_cgroup_private_id_put(id, nr_pages); } rcu_read_unlock(); } --- a/mm/memcontrol-v1.c~memcg-manipulate-memcg-private-id-references-by-id +++ a/mm/memcontrol-v1.c @@ -268,7 +268,7 @@ void memcg1_commit_charge(struct folio * */ void __memcg1_swapout(struct folio *folio, struct swap_cluster_info *ci) { - struct mem_cgroup *memcg, *swap_memcg; + struct mem_cgroup *memcg; struct obj_cgroup *objcg; unsigned int nr_entries; unsigned short private_id; @@ -298,9 +298,8 @@ void __memcg1_swapout(struct folio *foli * if the ID refers to the root memcg. */ nr_entries = folio_nr_pages(folio); - swap_memcg = mem_cgroup_private_id_get_online(memcg, nr_entries); - private_id = mem_cgroup_private_id(swap_memcg); - mod_memcg_state(swap_memcg, MEMCG_SWAP, nr_entries); + private_id = mem_cgroup_private_id_get(memcg, nr_entries); + mod_memcg_state(memcg, MEMCG_SWAP, nr_entries); __swap_cgroup_set(ci, swp_cluster_offset(folio->swap), nr_entries, private_id); --- a/mm/memcontrol-v1.h~memcg-manipulate-memcg-private-id-references-by-id +++ a/mm/memcontrol-v1.h @@ -27,8 +27,7 @@ static inline bool mem_cgroup_private_id return id == mem_cgroup_private_id(root_mem_cgroup); } -struct mem_cgroup *mem_cgroup_private_id_get_online(struct mem_cgroup *memcg, - unsigned int n); +unsigned short mem_cgroup_private_id_get(struct mem_cgroup *memcg, unsigned int n); void reparent_memcg_lruvec_state_local(struct mem_cgroup *memcg, struct mem_cgroup *parent, int idx); _ Patches currently in -mm which might be from bingfangguo@tencent.com are