From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-170.mta0.migadu.com (out-170.mta0.migadu.com [91.218.175.170]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 91C222E7391 for ; Thu, 16 Jul 2026 03:18:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.170 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784171928; cv=none; b=sWKDAVJBczK12jNm5eH1r5apIz/0U0186bY2c1neyydRZX+vegQSU5nY1qjFqoqhLTS3cArR+n5qWFW5E7YlBmFI6pnO9dH9wg0eSkcnF6ssX7MyFww0aw/VjkbKbCLSgnhOzTcB+podO3BXn0kkU5OzZnblDQ0kS4ppmRSbJQ8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784171928; c=relaxed/simple; bh=MPU69xsgJ/svd3IcmqExyPDpsX5dMaV1S1dcl1cebrY=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=VW++mm6Pj5q+iFfvCm8QpLjEvPUa80l3bMfHZV8QpF2u/B4Ua6+1oy4yBztIGe+j9Vu326ZhbTVoiMny5cFXOpIN1N5fgnq/cjucH3vdrBt4bgut8jVKYnpzsCCutV0ECshpiT54nCwnu1VUShfHMlYeUIYqLXBPPQ1Wf2r4uo8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=R2eswRyi; arc=none smtp.client-ip=91.218.175.170 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="R2eswRyi" X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1784171924; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=U+nRDyV396Q962ibdo2NRxaqklVXYG00a1pwNLPIQvc=; b=R2eswRyixwAbMb4BGDmXAlJb8JotNq8uS31sZKb+25YlEVlfX6/dyi5kncKI18ScuY5xG/ UolO/uUNk6uf7ypfNBSqMOP2hPAx8y88eH2tQXkit9m6GD8fz0UJlI5aYRE9KEzxM8IpkQ k0bFXOAZDAZJNGzMNRxW8Nda32NFX4g= From: Ridong To: Johannes Weiner , Michal Hocko , Roman Gushchin , Shakeel Butt , Andrew Morton , Chris Li , Kairui Song Cc: Muchun Song , Kemeng Shi , Nhat Pham , Baoquan He , Barry Song , Youngjun Park , David Hildenbrand , Qi Zheng , Lorenzo Stoakes , Axel Rasmussen , Yuanchu Xie , Wei Xu , Davidlohr Bueso , cgroups@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Ridong Chen , Ridong Chen Subject: [PATCH v2 1/2] memcg: move mem_cgroup_swappiness and vm_swappiness to mm/swap.h Date: Thu, 16 Jul 2026 11:17:28 +0800 Message-Id: <20260716031729.1064007-2-ridong.chen@linux.dev> In-Reply-To: <20260716031729.1064007-1-ridong.chen@linux.dev> References: <20260716031729.1064007-1-ridong.chen@linux.dev> Precedence: bulk X-Mailing-List: cgroups@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT From: Ridong Chen The per-memcg swappiness knob is v1-only; v2 always uses global vm_swappiness and ignores the per-cgroup field. Both mem_cgroup_swappiness() and vm_swappiness are only used within mm/ (memcontrol.c, memcontrol-v1.c, vmscan.c), so move them out of the public include/linux/swap.h into the mm-private mm/swap.h. This keeps unrelated declarations out of include/linux/swap.h. Guard memcg->swappiness with CONFIG_MEMCG_V1 as well, so v2-only kernels drop the unused field. No functional change for v1; v2-only kernels drop the unused field. Signed-off-by: Ridong Chen --- include/linux/memcontrol.h | 4 ++-- include/linux/swap.h | 19 ------------------- mm/memcontrol.c | 4 ++-- mm/swap.h | 20 ++++++++++++++++++++ 4 files changed, 24 insertions(+), 23 deletions(-) diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index 957260677678..e7a794dfb40e 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -239,8 +239,6 @@ struct mem_cgroup { */ bool oom_group; - int swappiness; - /* memory.events and memory.events.local */ struct cgroup_file events_file; struct cgroup_file events_local_file; @@ -318,6 +316,8 @@ struct mem_cgroup { /* List of events which userspace want to receive */ struct list_head event_list; spinlock_t event_list_lock; + + int swappiness; #endif /* CONFIG_MEMCG_V1 */ struct mem_cgroup_per_node *nodeinfo[]; diff --git a/include/linux/swap.h b/include/linux/swap.h index 696ed01709c2..330a420fd6de 100644 --- a/include/linux/swap.h +++ b/include/linux/swap.h @@ -309,7 +309,6 @@ static inline bool lru_cache_disabled(void) } extern unsigned long shrink_all_memory(unsigned long nr_pages); -extern int vm_swappiness; long remove_mapping(struct address_space *mapping, struct folio *folio); #if defined(CONFIG_SYSFS) && defined(CONFIG_NUMA) @@ -468,25 +467,7 @@ static inline int add_swap_extent(struct swap_info_struct *sis, } #endif /* CONFIG_SWAP */ #ifdef CONFIG_MEMCG -static inline int mem_cgroup_swappiness(struct mem_cgroup *memcg) -{ - /* Cgroup2 doesn't have per-cgroup swappiness */ - if (cgroup_subsys_on_dfl(memory_cgrp_subsys)) - return READ_ONCE(vm_swappiness); - - /* root ? */ - if (mem_cgroup_disabled() || mem_cgroup_is_root(memcg)) - return READ_ONCE(vm_swappiness); - - return READ_ONCE(memcg->swappiness); -} - void lru_reparent_memcg(struct mem_cgroup *memcg, struct mem_cgroup *parent, int nid); -#else -static inline int mem_cgroup_swappiness(struct mem_cgroup *memcg) -{ - return READ_ONCE(vm_swappiness); -} #endif #if defined(CONFIG_SWAP) && defined(CONFIG_MEMCG) && defined(CONFIG_BLK_CGROUP) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 22f55aeb94f3..d6ba276740ea 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -63,6 +63,7 @@ #include #include #include "internal.h" +#include "swap.h" #include "swap_table.h" #include #include @@ -4174,11 +4175,10 @@ mem_cgroup_css_alloc(struct cgroup_subsys_state *parent_css) #endif page_counter_set_high(&memcg->swap, PAGE_COUNTER_MAX); if (parent) { - WRITE_ONCE(memcg->swappiness, mem_cgroup_swappiness(parent)); - page_counter_init(&memcg->memory, &parent->memory, memcg_on_dfl); page_counter_init(&memcg->swap, &parent->swap, false); #ifdef CONFIG_MEMCG_V1 + WRITE_ONCE(memcg->swappiness, mem_cgroup_swappiness(parent)); memcg->memory.track_failcnt = !memcg_on_dfl; WRITE_ONCE(memcg->oom_kill_disable, READ_ONCE(parent->oom_kill_disable)); page_counter_init(&memcg->kmem, &parent->kmem, false); diff --git a/mm/swap.h b/mm/swap.h index b51ad3071a73..a0e04b97a466 100644 --- a/mm/swap.h +++ b/mm/swap.h @@ -4,6 +4,7 @@ #include /* for atomic_long_t */ #include /* for PAGE_SHIFT */ +#include /* for mem_cgroup_swappiness() */ struct mempolicy; struct swap_iocb; struct swap_memcg_table; @@ -76,6 +77,25 @@ enum swap_cluster_flags { CLUSTER_FLAG_MAX, }; +extern int vm_swappiness; + +static inline int mem_cgroup_swappiness(struct mem_cgroup *memcg) +{ +#ifdef CONFIG_MEMCG_V1 + /* Cgroup2 doesn't have per-cgroup swappiness */ + if (cgroup_subsys_on_dfl(memory_cgrp_subsys)) + return READ_ONCE(vm_swappiness); + + /* root ? */ + if (mem_cgroup_disabled() || mem_cgroup_is_root(memcg)) + return READ_ONCE(vm_swappiness); + + return READ_ONCE(memcg->swappiness); +#else + return READ_ONCE(vm_swappiness); +#endif +} + #ifdef CONFIG_SWAP #include /* for swp_offset */ #include /* for bio_end_io_t */ -- 2.34.1