From nobody Sat Jul 25 16:50:44 2026 Received: from out-177.mta0.migadu.com (out-177.mta0.migadu.com [91.218.175.177]) (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 6EA2B2D8DDF for ; Thu, 16 Jul 2026 03:18:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.177 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784171928; cv=none; b=Suxf7hbTJRD/VVXqSgjerP1nRYvVHNqmJR6RInXNCNpC+scZ33Hz19YD7F5Mg5WFrIoX9+WN1lkR9VX7paVCyDONW6+xNfsn8ff88g1b31LcG/YZZQL6s7k2PRITtrIIyDOWp2+UpPNi+v7kY+pwe8DCk/Ueuqy1Yugpn3lNtaE= 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=91.218.175.177 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: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Migadu-Flow: FLOW_OUT Content-Type: text/plain; charset="utf-8" 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 Acked-by: Johannes Weiner Reviewed-by: Barry Song Reviewed-by: Song Hu --- 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; =20 - 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 */ =20 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) } =20 extern unsigned long shrink_all_memory(unsigned long nr_pages); -extern int vm_swappiness; long remove_mapping(struct address_space *mapping, struct folio *folio); =20 #if defined(CONFIG_SYSFS) && defined(CONFIG_NUMA) @@ -468,25 +467,7 @@ static inline int add_swap_extent(struct swap_info_str= uct *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 *paren= t, int nid); -#else -static inline int mem_cgroup_swappiness(struct mem_cgroup *memcg) -{ - return READ_ONCE(vm_swappiness); -} #endif =20 #if defined(CONFIG_SWAP) && defined(CONFIG_MEMCG) && defined(CONFIG_BLK_CG= ROUP) 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 *pa= rent_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 =3D !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 @@ =20 #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, }; =20 +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 */ --=20 2.34.1 From nobody Sat Jul 25 16:50:44 2026 Received: from out-189.mta0.migadu.com (out-189.mta0.migadu.com [91.218.175.189]) (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 AC2262EBB8D for ; Thu, 16 Jul 2026 03:19:00 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.189 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784171942; cv=none; b=r+Aw7JJ0FkbogvdnNNUV4jEnMHcMlQc76ammnLpzVObk0eRgfyKPTnmiYvsDph4GJSnnuoxbrXuyz+/iPrl1WS4Nhrbj1Y6Ey9IgpTau+ssNqjHbYO/BcOC2i7pjJol9ak6Oc3/k6qw9NMpJ0YWIxU+JaeoiLKlbdKJQN0ml4jA= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784171942; c=relaxed/simple; bh=ZtzyzWp9Hgr1m5lQFzzbe5uY6ndBEnGQz9PtUl9w+4Q=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=nf0kRCQnC6eVT2cUHo3fxtxZOZ4Lu3oMdR8yQ6EB+2I5KGBQDnWzNbyjAZqtix8U8/hHTBW1pN1P5ZGI98HTE0UN41gH5bwuN5g17dNlSzUbw5FcI9pJjzt33/CIwJGY9jiS+nzcFceJaZpXV9U0EjI+p5VphWxsBBpME4PVeYg= 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=oAjDD2Dp; arc=none smtp.client-ip=91.218.175.189 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="oAjDD2Dp" 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=1784171938; 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=F2+wiVXqFER56suiYoyluTh0yWbLBUPuPSa5i4pNZtw=; b=oAjDD2DpPLx2y9QSnMyAFBPveYRCeMghBcqkdxtvOR9T/UEs6XEs8tW+NrTh/JNIun8I5D 2js20WvXL/faUC9EDv3qfo0IFZ4OfkBlNIb8a2so502eCSH0uFq85rCsvSNeRGpbkMO3FM aEpKNADeVm/Jkm8GTBmu+fA/Tr1t49k= 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 , stable@vger.kernel.org Subject: [PATCH v2 2/2] mm: vmscan: fix node reclaim ignoring swappiness parameter Date: Thu, 16 Jul 2026 11:17:29 +0800 Message-Id: <20260716031729.1064007-3-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: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Migadu-Flow: FLOW_OUT Content-Type: text/plain; charset="utf-8" From: Ridong Chen sc_swappiness() had two separate definitions depending on CONFIG_MEMCG. The !CONFIG_MEMCG variant simply returned vm_swappiness, ignoring the proactive_swappiness value passed through scan_control. This caused the swappiness parameter written to /sys/devices/system/node/nodeX/reclaim to have no effect when CONFIG_MEMCG is disabled. Fix this by consolidating sc_swappiness() into a single definition that checks sc->proactive_swappiness first, then falls back to mem_cgroup_swappiness() which already handles both CONFIG_MEMCG and !CONFIG_MEMCG. Before fix (swappiness=3Dmax ignored, mostly file pages reclaimed): # cat /proc/sys/vm/swappiness 60 # cat /proc/vmstat | grep pgsteal pgsteal_kswapd 0 pgsteal_direct 0 pgsteal_khugepaged 0 pgsteal_proactive 1840 pgsteal_anon 25 pgsteal_file 1815 # echo "64M swappiness=3Dmax" > /sys/devices/system/node/node0/reclaim # cat /proc/vmstat | grep pgsteal pgsteal_kswapd 0 pgsteal_direct 0 pgsteal_khugepaged 0 pgsteal_proactive 18013 pgsteal_anon 337 pgsteal_file 17676 After fix (swappiness=3Dmax honored, anon pages reclaimed as expected): # cat /proc/vmstat | grep pgsteal pgsteal_kswapd 0 pgsteal_direct 0 pgsteal_khugepaged 0 pgsteal_proactive 0 pgsteal_anon 0 pgsteal_file 0 # echo "64M swappiness=3Dmax" > /sys/devices/system/node/node0/reclaim # cat /proc/vmstat | grep pgsteal pgsteal_kswapd 0 pgsteal_direct 0 pgsteal_khugepaged 0 pgsteal_proactive 16283 pgsteal_anon 16283 pgsteal_file 0 Cc: stable@vger.kernel.org # 6.17+ Fixes: b980077899ea ("mm: introduce per-node proactive reclaim interface") Signed-off-by: Ridong Chen Acked-by: Johannes Weiner Reviewed-by: Barry Song Acked-by: Qi Zheng Reviewed-by: Song Hu Tested-by: Song Hu --- mm/vmscan.c | 19 +++++++------------ 1 file changed, 7 insertions(+), 12 deletions(-) diff --git a/mm/vmscan.c b/mm/vmscan.c index 986dde8e7429..bd71595c8b2b 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -199,6 +199,13 @@ struct scan_control { */ int vm_swappiness =3D 60; =20 +static int sc_swappiness(struct scan_control *sc, struct mem_cgroup *memcg) +{ + if (sc->proactive && sc->proactive_swappiness) + return *sc->proactive_swappiness; + return mem_cgroup_swappiness(memcg); +} + #ifdef CONFIG_MEMCG =20 /* Returns true for reclaim through cgroup limits or cgroup interfaces. */ @@ -239,13 +246,6 @@ static bool writeback_throttling_sane(struct scan_cont= rol *sc) #endif return false; } - -static int sc_swappiness(struct scan_control *sc, struct mem_cgroup *memcg) -{ - if (sc->proactive && sc->proactive_swappiness) - return *sc->proactive_swappiness; - return mem_cgroup_swappiness(memcg); -} #else static bool cgroup_reclaim(struct scan_control *sc) { @@ -261,11 +261,6 @@ static bool writeback_throttling_sane(struct scan_cont= rol *sc) { return true; } - -static int sc_swappiness(struct scan_control *sc, struct mem_cgroup *memcg) -{ - return READ_ONCE(vm_swappiness); -} #endif =20 static void set_task_reclaim_state(struct task_struct *task, --=20 2.34.1