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=1792832264; b=dnOgybTTomi451EHZZb+UVTYBG9QmWtIRHSlX2y8yrSbbHcS0PuCRKHSCD2q5n+5rqcz XtIee2DTrW9CtmWwEDbdF0NhqLV/GYp39X1FxVYvEB+/SFO4Fz5QFv5xlAqnjlBB9c15q HDiOfFsOR0XeEpitrSFVZQqwRQ3itUXjQIDx9Spkm3g+RkJaBKpIeaqRB4hSMpW8XNGoz uc9+msuLovZGb/rKHlitDaTzPGpdmoQXodQSSm3qZCYYQZ8A9ENcbCk2FnjjXYZBzhPj/ /s0sU5wyErP0okMjfwZLuARF51H8uCrQYSOiZwV4v6AGY5t4JX3YB1PQabbhR2FiArg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792832264; h=Received:DKIM-Signature:Date:To:From:Subject:Message-Id; bh=/hR/Cy1kNQaNRw7GxeaSj0BGiS+csPdoUcEVeM2Tt1g=; b=qMIptHEVLAM9DHxzFAXcStaUE3sE2Lp/7oIFmdNYtSWxvvUkvgJrSHaM1FJtfXw7T2Li 8kS0XDpq8k71VRv7eqGhky+351Ik/nwxhpviYXui6yErNJwDSzqW29Fm4up0bh06Z9ZE6 riQfsTJSQeVkprndb4YYQnd79RI0RC/DBloWtbE/5cN3hX5Ahb+AiPf4gUInXdyTUtIdn HzSzQ9gm105Y6ZHb1bPEhBnqPGvcyfnhrIU9Jijew0tXYZeSEkkgBUbns01Yejh1pZFDA uQWAGtAHqeYObl8o74GfhllbtadrCCE0a8qDSkO7xAQ8kVcs8+/OB0Nser1Osh69ODw== 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=WKP9rZvE; 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 D0006606A31B for ; Sat, 24 Oct 2026 08:57:43 +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=WKP9rZvE Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9EFCB1F031E0; Sat, 24 Oct 2026 08:57:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=korg; t=1792832263; bh=/hR/Cy1kNQaNRw7GxeaSj0BGiS+csPdoUcEVeM2Tt1g=; h=Date:To:From:Subject; b=WKP9rZvEWPS9+6UPr93SU/3ecQrsNV08lLDB2OtsFAmosj53e/wVuDnlp6pfrlHFq c10Hcq2qMoiMVfeAUmr8SiNs+CRBNRqQUZ3dBRg+qq8DGkmKRdWPLHtrkNn+GHmv48 4VGuVj+jOctxjBfdPvBOiC0WmrGg0j8OwYyc5JB0= Date: Sat, 24 Oct 2026 01:57:43 -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-base-swap-charge-accounting-on-memcgid-root-status.patch removed from -mm tree Message-Id: <20261024085743.9EFCB1F031E0@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: base swap charge accounting on memcgid root status has been removed from the -mm tree. Its filename was memcg-base-swap-charge-accounting-on-memcgid-root-status.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: base swap charge accounting on memcgid root status Date: Mon, 21 Sep 2026 14:16:25 +0800 A private ID currently pins its original memcg, so testing whether the ID belongs to root is equivalent to testing whether the resolved memcg is root. That equivalence will no longer hold when IDs refer to objcgs. A non-root ID may resolve to root after reparenting, but its swap entries still carry counter charges inherited by root. Skipping their uncharge based on the resolved memcg would leave those charges behind. Use the private ID's root status to decide whether a swap entry carries a counter charge. A root-ID entry carries none, while a non-root-ID entry must release its charge even if its current accounting memcg has become root. This patch adds a new helper to check if the memcgid equals to that of the root memcg. For swap uncharging and v2 swap charging, simply decide whether to charge/uncharge memsw or swap counter based on the swap memcgid is root or not. For v1 swapout, don't recharge the memsw counter, just cancel the charge if the swap memcg ID refers to the root memcg. This makes memory and swap charging have similar semantics: one relys on the objcg's root status, and the other relys on the memcgid's root status. Link: https://lore.kernel.org/20260921-bingfangguo-memcgid-rework-v2-2-6c0637dc0edb@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 | 16 ++++++++-------- mm/memcontrol-v1.h | 5 +++++ mm/memcontrol.c | 4 ++-- 3 files changed, 15 insertions(+), 10 deletions(-) --- a/mm/memcontrol.c~memcg-base-swap-charge-accounting-on-memcgid-root-status +++ a/mm/memcontrol.c @@ -5975,7 +5975,7 @@ int __mem_cgroup_try_charge_swap(struct /* memcg is pined by memcg ID. */ private_id = mem_cgroup_private_id(memcg); - if (!mem_cgroup_is_root(memcg) && + 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); @@ -6004,7 +6004,7 @@ void __mem_cgroup_uncharge_swap(unsigned rcu_read_lock(); memcg = mem_cgroup_from_private_id(id); if (memcg) { - if (!mem_cgroup_is_root(memcg)) { + if (!mem_cgroup_private_id_is_root(id)) { if (do_memsw_account()) page_counter_uncharge(&memcg->memsw, nr_pages); else --- a/mm/memcontrol-v1.c~memcg-base-swap-charge-accounting-on-memcgid-root-status +++ a/mm/memcontrol-v1.c @@ -271,6 +271,7 @@ void __memcg1_swapout(struct folio *foli struct mem_cgroup *memcg, *swap_memcg; struct obj_cgroup *objcg; unsigned int nr_entries; + unsigned short private_id; VM_WARN_ON_ONCE_FOLIO(!folio_test_swapcache(folio), folio); VM_WARN_ON_ONCE_FOLIO(!folio_test_locked(folio), folio); @@ -293,25 +294,24 @@ void __memcg1_swapout(struct folio *foli /* * In case the memcg owning these pages has been offlined and doesn't * have an ID allocated to it anymore, charge the closest online - * ancestor for the swap instead and transfer the memory+swap charge. + * ancestor for the swap instead and cancel the memory+swap charge + * 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); - __swap_cgroup_set(ci, swp_cluster_offset(folio->swap), nr_entries, - mem_cgroup_private_id(swap_memcg)); + __swap_cgroup_set(ci, swp_cluster_offset(folio->swap), nr_entries, private_id); folio_unqueue_deferred_split(folio); folio->memcg_data = 0; - if (!obj_cgroup_is_root(objcg)) + if (!obj_cgroup_is_root(objcg)) { page_counter_uncharge(&memcg->memory, nr_entries); - if (memcg != swap_memcg) { - if (!mem_cgroup_is_root(swap_memcg)) - page_counter_charge(&swap_memcg->memsw, nr_entries); - page_counter_uncharge(&memcg->memsw, nr_entries); + if (mem_cgroup_private_id_is_root(private_id)) + page_counter_uncharge(&memcg->memsw, nr_entries); } /* --- a/mm/memcontrol-v1.h~memcg-base-swap-charge-accounting-on-memcgid-root-status +++ a/mm/memcontrol-v1.h @@ -22,6 +22,11 @@ void drain_all_stock(struct mem_cgroup * int memory_stat_show(struct seq_file *m, void *v); +static inline bool mem_cgroup_private_id_is_root(unsigned short 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); _ Patches currently in -mm which might be from bingfangguo@tencent.com are