From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 1846DCA1013 for ; Fri, 19 Sep 2025 03:49:57 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 643DE8E00FB; Thu, 18 Sep 2025 23:49:56 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 5CE418E0008; Thu, 18 Sep 2025 23:49:56 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 494B28E00FB; Thu, 18 Sep 2025 23:49:56 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id 3143A8E0008 for ; Thu, 18 Sep 2025 23:49:56 -0400 (EDT) Received: from smtpin28.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay04.hostedemail.com (Postfix) with ESMTP id EBA361A0517 for ; Fri, 19 Sep 2025 03:49:55 +0000 (UTC) X-FDA: 83904621150.28.FC44284 Received: from mail-pg1-f171.google.com (mail-pg1-f171.google.com [209.85.215.171]) by imf25.hostedemail.com (Postfix) with ESMTP id 145E8A0004 for ; Fri, 19 Sep 2025 03:49:53 +0000 (UTC) Authentication-Results: imf25.hostedemail.com; dkim=pass header.d=bytedance.com header.s=google header.b=PVx1OChJ; spf=pass (imf25.hostedemail.com: domain of zhengqi.arch@bytedance.com designates 209.85.215.171 as permitted sender) smtp.mailfrom=zhengqi.arch@bytedance.com; dmarc=pass (policy=quarantine) header.from=bytedance.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1758253794; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=pH+wF1kXarYaSv3rskQg/2hJ0DlvmAW+2Zdq+CMJuUY=; b=gtU+LKecyg931AaLqAiTYbDQgZWaxstz8ftRGpndw072h3HA2vYUtsRhmJrM/5BR0vHbmy kpYeCWH7YhJk794AB/jKk5vlEg1QUVfgJTCX2KHXIlqx1Amr7MF2PSDpv25XgbFQQVDF6D jt0sFejKasRZSf6EAqIRR45O6JmAaB8= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1758253794; a=rsa-sha256; cv=none; b=Qvdyv8PR/Khs2KQinWsTDlS497SCfK75rLy2Sqb1wx3GR04sxDXnCYRLE8INn14X9cJToo 73UZ5rOnWEPR9IDMIgTs+qYGCz9NznIGvyX5NvQOTn0oZrRGJXV0pdlltQBFbr1c9zCVEb GOW8qwLinV/vd3GAWGxg6A+FlwnURz0= ARC-Authentication-Results: i=1; imf25.hostedemail.com; dkim=pass header.d=bytedance.com header.s=google header.b=PVx1OChJ; spf=pass (imf25.hostedemail.com: domain of zhengqi.arch@bytedance.com designates 209.85.215.171 as permitted sender) smtp.mailfrom=zhengqi.arch@bytedance.com; dmarc=pass (policy=quarantine) header.from=bytedance.com Received: by mail-pg1-f171.google.com with SMTP id 41be03b00d2f7-b5524c0ed94so14505a12.3 for ; Thu, 18 Sep 2025 20:49:53 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance.com; s=google; t=1758253793; x=1758858593; darn=kvack.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=pH+wF1kXarYaSv3rskQg/2hJ0DlvmAW+2Zdq+CMJuUY=; b=PVx1OChJqQrfaIMgg3BTUtcgCeQ8HRonGHC+ahOeiizM99dw1qdwC8PDT7f6Kj4ij8 9yM8SmF7L0yHq5WalW8DOfq1u5n6rm6VVwTUmPDKUZJlYgv5N9Cjxj0p8JDX5QPL8kTb GYgnfkPHUwPFQa3+bIJm1mY5v5JnNwHBEOZnckshsuzI1tVJhGb8fDpCuwMabSg8OxQL 9+Tc0z2Zj/VPVRJF5bhsxYCsKPV1gwU4uzVERuz8aEQSI+Oeorp00+l65LLjEZtJfya+ F/AFFcZKZEBkpFtPjNe2/sWXjoGIOo0/hGxg7gH++b22e4PcsfFxSXlU0+aHTFcKIgoF v0Kw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1758253793; x=1758858593; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=pH+wF1kXarYaSv3rskQg/2hJ0DlvmAW+2Zdq+CMJuUY=; b=leRZR/+LdkvllGxSfZt55iBc7+zF0oWKYPW1BQZBpwhmT/wkZ1w4cIdw53UCzN41lh 9zZhF/B5eBBX1JOol+82VrXiQm2mzGRxgTV7Q+cCjk+uJGrx/TN7hzWqL23UpNFmhq4f PIAcnde3NzQQDA9eqjNSH23kH8VHTXrysrMAFNZjIWlarFCo+7hM/Jy4Stu0ESD8dosl SUPeett+OIwc3zGA2pdSPPw5DalC7poBFQ+LGxEesLQAbEkbUeoL+3T+JHUXgAA+PlK3 R+6sGDDduMDGOPRyge4Qhi49uQwHxZuvyTLV9vIufFiQ61xi/dGVJo3VCWpZiF0agLO1 X5Tw== X-Gm-Message-State: AOJu0YwEPGklyzYaUW3rbja86UuInyKcxt9Hekrh11zb48UIFzmag659 Nhb0qNKvBM9GNm5OoT30RLZzV7kgS6Weml8uu33QUq+iUtk2Ktz33wfszNX+noIsE0k= X-Gm-Gg: ASbGnctwJ4ZkAGwBNWFvDgZ/o3/gWJxsyD0JxNm3UMaR6I1OsdMmIe/jWpZbXO98wkF 0gqxPtt96NK75k4bwDKx6OFnNofINdIOWbf4+aSMwOC3E3o62gu0p+ZrdBiKnz86zHPpnX6T/lZ qifxD17SKfda7dReb5KwckFOAJc3tfKscxfFNHnihc9Kc92wKXg7r5X8ukPnndwOVeVZ3m/ovgf CHbzJJEMMYbspDWns6yTChjawBkcFV6JQceE0CB1Qh+VUFwzdyytXe4RMQm49mxMleNmIkxSbS9 qgnaARq+XTKqaa4vPAn/3cmwA4ZOFYDn/ZwrUb1Oco1YL0f2NcBXFw0vesJ1Fdudpv1pRpDkiGs IZ0UHDDQ89qYuWAhkEJ+Cj9wWr1meRkgQq6ODCKFH3s8INsg+cOiWbC1iGg4vD0h6gZWwC3g= X-Google-Smtp-Source: AGHT+IE5FHZ53nVuEAm0EyvYyGaqEltHg/7s5hCn2sKWBeSzIX/++Bb6G05UYvRwpJYwFHv887Zr4Q== X-Received: by 2002:a17:902:ccd2:b0:252:50ad:4e6f with SMTP id d9443c01a7336-269ba566603mr31897395ad.54.1758253792612; Thu, 18 Sep 2025 20:49:52 -0700 (PDT) Received: from G7HT0H2MK4.bytedance.net ([63.216.146.178]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-269802de5e9sm39629235ad.72.2025.09.18.20.49.44 (version=TLS1_3 cipher=TLS_CHACHA20_POLY1305_SHA256 bits=256/256); Thu, 18 Sep 2025 20:49:52 -0700 (PDT) From: Qi Zheng To: hannes@cmpxchg.org, hughd@google.com, mhocko@suse.com, roman.gushchin@linux.dev, shakeel.butt@linux.dev, muchun.song@linux.dev, david@redhat.com, lorenzo.stoakes@oracle.com, ziy@nvidia.com, baolin.wang@linux.alibaba.com, Liam.Howlett@oracle.com, npache@redhat.com, ryan.roberts@arm.com, dev.jain@arm.com, baohua@kernel.org, lance.yang@linux.dev, akpm@linux-foundation.org Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, Muchun Song , Qi Zheng Subject: [PATCH 2/4] mm: thp: introduce folio_split_queue_lock and its variants Date: Fri, 19 Sep 2025 11:46:33 +0800 Message-ID: X-Mailer: git-send-email 2.48.1 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Queue-Id: 145E8A0004 X-Stat-Signature: m3ohcdie53cynwztu775fuakgfe4e8rs X-Rspam-User: X-Rspamd-Server: rspam09 X-HE-Tag: 1758253793-474447 X-HE-Meta: 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 pe7eNAGI cP67pasHG/FbEq91Kia81nF9CrV1qQCSFM6z95DTnrC9GQKq5bouWDNJEVooTz5ULT1/FsofUtjdMzH3q7qYraGMIuLXajqPeOCKqVaJv7hJHEf4WgfSr7nhN+O3C3SOPXrSOiLDUWzy8lB5VlZX8V+8h2GtynAFHSEAf8tcX0eq5rdHY2dWCout2XBS0KKcyDou3PJI5xPEpjQJzzrzoJn5CjvDbPESczCZyfhNoZNvtqbuid+6M9tdI/SuIfotiRr9PE2uKxP6/crrMe9KVBfmEIWh2yfHk812Sp8x/KoGEO9KV6LG4d8o4hrkpqOh7Bh71ndljCPCMHeHkQ4vZ86xcxCTJdSV+Ht9xj0S/Wd6giWQSuiBBmLEwkYVdNVVHAs6ogVyoSeZTvAw79uXDQRzqPLrGPDEYBIGglSlqGj6AjZ7N3nZDKccKG4GluXwPyOMg 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: List-Subscribe: List-Unsubscribe: From: Muchun Song In future memcg removal, the binding between a folio and a memcg may change, making the split lock within the memcg unstable when held. A new approach is required to reparent the split queue to its parent. This patch starts introducing a unified way to acquire the split lock for future work. It's a code-only refactoring with no functional changes. Signed-off-by: Muchun Song Acked-by: Johannes Weiner Signed-off-by: Qi Zheng --- include/linux/memcontrol.h | 10 +++++ mm/huge_memory.c | 89 ++++++++++++++++++++++++++------------ 2 files changed, 71 insertions(+), 28 deletions(-) diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index 16fe0306e50ea..99876af13c315 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -1662,6 +1662,11 @@ int alloc_shrinker_info(struct mem_cgroup *memcg); void free_shrinker_info(struct mem_cgroup *memcg); void set_shrinker_bit(struct mem_cgroup *memcg, int nid, int shrinker_id); void reparent_shrinker_deferred(struct mem_cgroup *memcg); + +static inline int shrinker_id(struct shrinker *shrinker) +{ + return shrinker->id; +} #else #define mem_cgroup_sockets_enabled 0 @@ -1693,6 +1698,11 @@ static inline void set_shrinker_bit(struct mem_cgroup *memcg, int nid, int shrinker_id) { } + +static inline int shrinker_id(struct shrinker *shrinker) +{ + return -1; +} #endif #ifdef CONFIG_MEMCG diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 582628ddf3f33..d34516a22f5bb 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -1078,26 +1078,62 @@ pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma) #ifdef CONFIG_MEMCG static inline -struct deferred_split *get_deferred_split_queue(struct folio *folio) +struct mem_cgroup *folio_split_queue_memcg(struct folio *folio, + struct deferred_split *queue) { - struct mem_cgroup *memcg = folio_memcg(folio); - struct pglist_data *pgdat = NODE_DATA(folio_nid(folio)); - - if (memcg) - return &memcg->deferred_split_queue; - else - return &pgdat->deferred_split_queue; + if (mem_cgroup_disabled()) + return NULL; + if (&NODE_DATA(folio_nid(folio))->deferred_split_queue == queue) + return NULL; + return container_of(queue, struct mem_cgroup, deferred_split_queue); } #else static inline -struct deferred_split *get_deferred_split_queue(struct folio *folio) +struct mem_cgroup *folio_split_queue_memcg(struct folio *folio, + struct deferred_split *queue) { - struct pglist_data *pgdat = NODE_DATA(folio_nid(folio)); - - return &pgdat->deferred_split_queue; + return NULL; } #endif +static struct deferred_split *folio_split_queue_lock(struct folio *folio) +{ + struct mem_cgroup *memcg; + struct deferred_split *queue; + + memcg = folio_memcg(folio); + queue = memcg ? &memcg->deferred_split_queue : + &NODE_DATA(folio_nid(folio))->deferred_split_queue; + spin_lock(&queue->split_queue_lock); + + return queue; +} + +static struct deferred_split * +folio_split_queue_lock_irqsave(struct folio *folio, unsigned long *flags) +{ + struct mem_cgroup *memcg; + struct deferred_split *queue; + + memcg = folio_memcg(folio); + queue = memcg ? &memcg->deferred_split_queue : + &NODE_DATA(folio_nid(folio))->deferred_split_queue; + spin_lock_irqsave(&queue->split_queue_lock, *flags); + + return queue; +} + +static inline void split_queue_unlock(struct deferred_split *queue) +{ + spin_unlock(&queue->split_queue_lock); +} + +static inline void split_queue_unlock_irqrestore(struct deferred_split *queue, + unsigned long flags) +{ + spin_unlock_irqrestore(&queue->split_queue_lock, flags); +} + static inline bool is_transparent_hugepage(const struct folio *folio) { if (!folio_test_large(folio)) @@ -3579,7 +3615,7 @@ static int __folio_split(struct folio *folio, unsigned int new_order, struct page *split_at, struct page *lock_at, struct list_head *list, bool uniform_split) { - struct deferred_split *ds_queue = get_deferred_split_queue(folio); + struct deferred_split *ds_queue; XA_STATE(xas, &folio->mapping->i_pages, folio->index); struct folio *end_folio = folio_next(folio); bool is_anon = folio_test_anon(folio); @@ -3718,7 +3754,7 @@ static int __folio_split(struct folio *folio, unsigned int new_order, } /* Prevent deferred_split_scan() touching ->_refcount */ - spin_lock(&ds_queue->split_queue_lock); + ds_queue = folio_split_queue_lock(folio); if (folio_ref_freeze(folio, 1 + extra_pins)) { struct swap_cluster_info *ci = NULL; struct lruvec *lruvec; @@ -3740,7 +3776,7 @@ static int __folio_split(struct folio *folio, unsigned int new_order, */ list_del_init(&folio->_deferred_list); } - spin_unlock(&ds_queue->split_queue_lock); + split_queue_unlock(ds_queue); if (mapping) { int nr = folio_nr_pages(folio); @@ -3835,7 +3871,7 @@ static int __folio_split(struct folio *folio, unsigned int new_order, if (ci) swap_cluster_unlock(ci); } else { - spin_unlock(&ds_queue->split_queue_lock); + split_queue_unlock(ds_queue); ret = -EAGAIN; } fail: @@ -4016,8 +4052,7 @@ bool __folio_unqueue_deferred_split(struct folio *folio) WARN_ON_ONCE(folio_ref_count(folio)); WARN_ON_ONCE(!mem_cgroup_disabled() && !folio_memcg_charged(folio)); - ds_queue = get_deferred_split_queue(folio); - spin_lock_irqsave(&ds_queue->split_queue_lock, flags); + ds_queue = folio_split_queue_lock_irqsave(folio, &flags); if (!list_empty(&folio->_deferred_list)) { ds_queue->split_queue_len--; if (folio_test_partially_mapped(folio)) { @@ -4028,7 +4063,7 @@ bool __folio_unqueue_deferred_split(struct folio *folio) list_del_init(&folio->_deferred_list); unqueued = true; } - spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags); + split_queue_unlock_irqrestore(ds_queue, flags); return unqueued; /* useful for debug warnings */ } @@ -4036,10 +4071,7 @@ bool __folio_unqueue_deferred_split(struct folio *folio) /* partially_mapped=false won't clear PG_partially_mapped folio flag */ void deferred_split_folio(struct folio *folio, bool partially_mapped) { - struct deferred_split *ds_queue = get_deferred_split_queue(folio); -#ifdef CONFIG_MEMCG - struct mem_cgroup *memcg = folio_memcg(folio); -#endif + struct deferred_split *ds_queue; unsigned long flags; /* @@ -4062,7 +4094,7 @@ void deferred_split_folio(struct folio *folio, bool partially_mapped) if (folio_test_swapcache(folio)) return; - spin_lock_irqsave(&ds_queue->split_queue_lock, flags); + ds_queue = folio_split_queue_lock_irqsave(folio, &flags); if (partially_mapped) { if (!folio_test_partially_mapped(folio)) { folio_set_partially_mapped(folio); @@ -4077,15 +4109,16 @@ void deferred_split_folio(struct folio *folio, bool partially_mapped) VM_WARN_ON_FOLIO(folio_test_partially_mapped(folio), folio); } if (list_empty(&folio->_deferred_list)) { + struct mem_cgroup *memcg; + + memcg = folio_split_queue_memcg(folio, ds_queue); list_add_tail(&folio->_deferred_list, &ds_queue->split_queue); ds_queue->split_queue_len++; -#ifdef CONFIG_MEMCG if (memcg) set_shrinker_bit(memcg, folio_nid(folio), - deferred_split_shrinker->id); -#endif + shrinker_id(deferred_split_shrinker)); } - spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags); + split_queue_unlock_irqrestore(ds_queue, flags); } static unsigned long deferred_split_count(struct shrinker *shrink, -- 2.20.1