From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 CDAB53F8DE1 for ; Wed, 18 Mar 2026 20:13:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773864826; cv=none; b=G60Ghrr9xuhod39OwHTy2DCsXSgoy/IQ3B1ZZJapr+9Qxlz6fdlXIMNBTOVuNAWsxVkPmrw1ukmtX4Fb6NcBi/l37tmKho+KNQplq5v1diMry/S/la13/Tp79SCSg8rbxDPO5lcJoITbSYWbj2dIMNFqIYr7VSJRlFh5jT27Hdg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773864826; c=relaxed/simple; bh=xObn2v5WaVl8JdIeF+CLpoyaBfMFtqgO7e8ohsWFvcQ=; h=Date:To:From:Subject:Message-Id; b=JWALBY0p2Qo3mpuhd6icNi6QbGvwnSKh76AwZKauT6AOx2LwwgOcE7IqoX7MOqoRpDHw3TaOA/Tpeptc3eobXubsG0SJZNxLsCpFrP3ojVfP8Jxq3Fs9TiZA/wthhRbIt1GhhpqGuKXED7atqA1XtEHNYAXUYwNQ/P8IWj7YKPE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=yr5vUGNk; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="yr5vUGNk" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B0BF5C2BC9E; Wed, 18 Mar 2026 20:13:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1773864825; bh=xObn2v5WaVl8JdIeF+CLpoyaBfMFtqgO7e8ohsWFvcQ=; h=Date:To:From:Subject:From; b=yr5vUGNkGmT2/49Ibx3LQ8iesxIZXgiripCP205f0Rwy9q77pOSOOXSOIyYPiXavX X0HoD7oUb4LtZCsPLSACca1W97zJC5A8ZmPbKfuK+bHnHbNj1tw0KBn1rg3mr8EFuh 3vn0v355jeHChw86JDUwzveiyKDF0/lQ4d8N1zkQ= Date: Wed, 18 Mar 2026 13:13:45 -0700 To: mm-commits@vger.kernel.org,ziy@nvidia.com,yuanchu@google.com,weixugc@google.com,vbabka@kernel.org,surenb@google.com,shakeel.butt@linux.dev,ryan.roberts@arm.com,rppt@kernel.org,roman.gushchin@linux.dev,npache@redhat.com,muchun.song@linux.dev,mhocko@kernel.org,ljs@kernel.org,liam.howlett@oracle.com,lance.yang@linux.dev,dev.jain@arm.com,david@kernel.org,david@fromorbit.com,baolin.wang@linux.alibaba.com,baohua@kernel.org,axelrasmussen@google.com,hannes@cmpxchg.org,akpm@linux-foundation.org From: Andrew Morton Subject: + mm-list_lru-introduce-folio_memcg_list_lru_alloc.patch added to mm-new branch Message-Id: <20260318201345.B0BF5C2BC9E@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The patch titled Subject: mm: list_lru: introduce folio_memcg_list_lru_alloc() has been added to the -mm mm-new branch. Its filename is mm-list_lru-introduce-folio_memcg_list_lru_alloc.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-list_lru-introduce-folio_memcg_list_lru_alloc.patch This patch will later appear in the mm-new branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Note, mm-new is a provisional staging ground for work-in-progress patches, and acceptance into mm-new is a notification for others take notice and to finish up reviews. Please do not hesitate to respond to review feedback and post updated versions to replace or incrementally fixup patches in mm-new. The mm-new branch of mm.git is not included in linux-next If a few days of testing in mm-new is successful, the patch will me moved into mm.git's mm-unstable branch, which is included in linux-next Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via various branches at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there most days ------------------------------------------------------ From: Johannes Weiner Subject: mm: list_lru: introduce folio_memcg_list_lru_alloc() Date: Wed, 18 Mar 2026 15:53:24 -0400 memcg_list_lru_alloc() is called every time an object that may end up on the list_lru is created. It needs to quickly check if the list_lru heads for the memcg already exist, and allocate them when they don't. Doing this with folio objects is tricky: folio_memcg() is not stable and requires either RCU protection or pinning the cgroup. But it's desirable to make the existence check lightweight under RCU, and only pin the memcg when we need to allocate list_lru heads and may block. In preparation for switching the THP shrinker to list_lru, add a helper function for allocating list_lru heads coming from a folio. Link: https://lkml.kernel.org/r/20260318200352.1039011-7-hannes@cmpxchg.org Signed-off-by: Johannes Weiner Reviewed-by: David Hildenbrand (Arm) Cc: Axel Rasmussen Cc: Baolin Wang Cc: Barry Song Cc: Dave Chinner Cc: Dev Jain Cc: Lance Yang Cc: Liam Howlett Cc: Lorenzo Stoakes Cc: Michal Hocko Cc: Mike Rapoport Cc: Muchun Song Cc: Nico Pache Cc: Roman Gushchin Cc: Ryan Roberts Cc: Shakeel Butt Cc: Suren Baghdasaryan Cc: Vlastimil Babka Cc: Wei Xu Cc: Yuanchu Xie Cc: Zi Yan Signed-off-by: Andrew Morton --- include/linux/list_lru.h | 12 +++++++++++ mm/list_lru.c | 39 ++++++++++++++++++++++++++++++++----- 2 files changed, 46 insertions(+), 5 deletions(-) --- a/include/linux/list_lru.h~mm-list_lru-introduce-folio_memcg_list_lru_alloc +++ a/include/linux/list_lru.h @@ -81,6 +81,18 @@ static inline int list_lru_init_memcg_ke int memcg_list_lru_alloc(struct mem_cgroup *memcg, struct list_lru *lru, gfp_t gfp); + +#ifdef CONFIG_MEMCG +int folio_memcg_list_lru_alloc(struct folio *folio, struct list_lru *lru, + gfp_t gfp); +#else +static inline int folio_memcg_list_lru_alloc(struct folio *folio, + struct list_lru *lru, gfp_t gfp) +{ + return 0; +} +#endif + void memcg_reparent_list_lrus(struct mem_cgroup *memcg, struct mem_cgroup *parent); /** --- a/mm/list_lru.c~mm-list_lru-introduce-folio_memcg_list_lru_alloc +++ a/mm/list_lru.c @@ -537,17 +537,14 @@ static inline bool memcg_list_lru_alloca return idx < 0 || xa_load(&lru->xa, idx); } -int memcg_list_lru_alloc(struct mem_cgroup *memcg, struct list_lru *lru, - gfp_t gfp) +static int __memcg_list_lru_alloc(struct mem_cgroup *memcg, + struct list_lru *lru, gfp_t gfp) { unsigned long flags; struct list_lru_memcg *mlru = NULL; struct mem_cgroup *pos, *parent; XA_STATE(xas, &lru->xa, 0); - if (!list_lru_memcg_aware(lru) || memcg_list_lru_allocated(memcg, lru)) - return 0; - gfp &= GFP_RECLAIM_MASK; /* * Because the list_lru can be reparented to the parent cgroup's @@ -588,6 +585,38 @@ int memcg_list_lru_alloc(struct mem_cgro return xas_error(&xas); } + +int memcg_list_lru_alloc(struct mem_cgroup *memcg, struct list_lru *lru, + gfp_t gfp) +{ + if (!list_lru_memcg_aware(lru) || memcg_list_lru_allocated(memcg, lru)) + return 0; + return __memcg_list_lru_alloc(memcg, lru, gfp); +} + +int folio_memcg_list_lru_alloc(struct folio *folio, struct list_lru *lru, + gfp_t gfp) +{ + struct mem_cgroup *memcg; + int res; + + if (!list_lru_memcg_aware(lru)) + return 0; + + /* Fast path when list_lru heads already exist */ + rcu_read_lock(); + memcg = folio_memcg(folio); + res = memcg_list_lru_allocated(memcg, lru); + rcu_read_unlock(); + if (likely(res)) + return 0; + + /* Allocation may block, pin the memcg */ + memcg = get_mem_cgroup_from_folio(folio); + res = __memcg_list_lru_alloc(memcg, lru, gfp); + mem_cgroup_put(memcg); + return res; +} #else static inline void memcg_init_list_lru(struct list_lru *lru, bool memcg_aware) { _ Patches currently in -mm which might be from hannes@cmpxchg.org are mm-vmalloc-streamline-vmalloc-memory-accounting.patch mm-memcontrol-switch-to-native-nr_vmalloc-vmstat-counter.patch mm-memcontrol-split-out-__obj_cgroup_charge.patch mm-memcontrol-use-__account_obj_stock-in-the-locked-path.patch mm-memcg-separate-slab-stat-accounting-from-objcg-charge-cache.patch mm-list_lru-lock_list_lru_of_memcg-cannot-return-null-if-skip_empty.patch mm-list_lru-deduplicate-unlock_list_lru.patch mm-list_lru-move-list-dead-check-to-lock_list_lru_of_memcg.patch mm-list_lru-deduplicate-lock_list_lru.patch mm-list_lru-introduce-caller-locking-for-additions-and-deletions.patch mm-list_lru-introduce-folio_memcg_list_lru_alloc.patch mm-switch-deferred-split-shrinker-to-list_lru.patch