From nobody Sun Feb 8 01:30:34 2026 Received: from out-186.mta1.migadu.com (out-186.mta1.migadu.com [95.215.58.186]) (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 798E71C4622 for ; Wed, 14 Aug 2024 20:28:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.186 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723667328; cv=none; b=C+w7gxu6Hl2SfYxsEktCvjkwdAHKIjvjzZ6L5LkKd8KTBDH3MTiSNCwhXnLXSN/bf9Hbh95+ePKgL6DC4W5WL8RSdoi6YRwV5UfZV3GSKEPpxjPa5Oj7E09L63JaAjqe7yss1o+YbEWBplqguDdBY+CoHvRN60wbMUG6yPoRZQo= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723667328; c=relaxed/simple; bh=uHdcF3T3rwDBJ90jLhPxGnFyBYsn6F3Ngqso8pIXwt0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=jX2SxlN5hPyp2BQW2G2UU+EwVLWcz0yrsC2Iv4aC37AYkzZzhDMXM7WNK/C19kVLwTjBJObQm05PPu4ojvp3Q9b6foU8YoLK7Ijzmc5gqfEo+wsLIwen1Y5gsHPUIBLkk30A7MjE77Bmhv92iQJ7qkYh2zCKHepCww6/f9MmR0w= 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=vvo2dAml; arc=none smtp.client-ip=95.215.58.186 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="vvo2dAml" 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=1723667324; 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=YuTcvSW9Di06EfL0eDnFgAZS8RJd4NfEvtxJHSVe1sg=; b=vvo2dAmlpYSQYHhGtKfIuWJfO+kJhk5WnvGdclU5CU9cDOmn/jsaasYKEFAhDLlCloevd3 +dExAtypgTNUQ+nNTXmJ/j/EFS1cHLkgaYnmoDiouffshNOgBHAapG+utAWl+Lu5osG6c9 CWLZZGuJQ1RMm71iqpLzwNABbwK/bLU= From: Shakeel Butt To: Andrew Morton Cc: Johannes Weiner , Michal Hocko , Roman Gushchin , Muchun Song , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Meta kernel team , cgroups@vger.kernel.org Subject: [PATCH 1/4] memcg: initiate deprecation of v1 tcp accounting Date: Wed, 14 Aug 2024 13:28:22 -0700 Message-ID: <20240814202825.2694077-2-shakeel.butt@linux.dev> In-Reply-To: <20240814202825.2694077-1-shakeel.butt@linux.dev> References: <20240814202825.2694077-1-shakeel.butt@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" Memcg v1 provides opt-in TCP memory accounting feature. However it is mostly unused due to its performance impact on the network traffic. In v2, the TCP memory is accounted in the regular memory usage and is transparent to the users but they can observe the TCP memory usage through memcg stats. Let's initiate the deprecation process of memcg v1's tcp accounting functionality and add warnings to gather if there are any users and if there are, collect how they are using it and plan to provide them better alternative in v2. Signed-off-by: Shakeel Butt Reviewed-by: T.J. Mercier --- Documentation/admin-guide/cgroup-v1/memory.rst | 8 ++++++++ mm/memcontrol-v1.c | 3 +++ 2 files changed, 11 insertions(+) diff --git a/Documentation/admin-guide/cgroup-v1/memory.rst b/Documentation= /admin-guide/cgroup-v1/memory.rst index 9cde26d33843..fb6d3e2a6395 100644 --- a/Documentation/admin-guide/cgroup-v1/memory.rst +++ b/Documentation/admin-guide/cgroup-v1/memory.rst @@ -105,10 +105,18 @@ Brief summary of control files. memory.kmem.max_usage_in_bytes show max kernel memory usage recorded =20 memory.kmem.tcp.limit_in_bytes set/show hard limit for tcp buf memory + This knob is deprecated and shouldn't= be + used. memory.kmem.tcp.usage_in_bytes show current tcp buf memory allocation + This knob is deprecated and shouldn't= be + used. memory.kmem.tcp.failcnt show the number of tcp buf memory usa= ge + This knob is deprecated and shouldn't= be + used. hits limits memory.kmem.tcp.max_usage_in_bytes show max tcp buf memory usage recorded + This knob is deprecated and shouldn't= be + used. =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D =20 1. History diff --git a/mm/memcontrol-v1.c b/mm/memcontrol-v1.c index 9725c731fb21..b8e2ee454eaa 100644 --- a/mm/memcontrol-v1.c +++ b/mm/memcontrol-v1.c @@ -2447,6 +2447,9 @@ static ssize_t mem_cgroup_write(struct kernfs_open_fi= le *of, ret =3D 0; break; case _TCP: + pr_warn_once("kmem.tcp.limit_in_bytes is deprecated and will be removed= . " + "Please report your usecase to linux-mm@kvack.org if you " + "depend on this functionality.\n"); ret =3D memcg_update_tcp_max(memcg, nr_pages); break; } --=20 2.43.5 From nobody Sun Feb 8 01:30:34 2026 Received: from out-186.mta0.migadu.com (out-186.mta0.migadu.com [91.218.175.186]) (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 D4E301C3F2A for ; Wed, 14 Aug 2024 20:28:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.186 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723667337; cv=none; b=leVqDI5FXOlHXD5HEuoR8Xc9W59p2IjNzcG6EouiCMPqb+xnsPuFEIWlaA8znAp22oJO/UL/QFzRxsoWV1Z0K54202X7iClUFRRlvR7w9PmxfvAG3ksmJGHHA0SGPW5NjCmYJ5hDUzlsLXuZgwowcmHPv7bDnGWCe+EUnS3x2NM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723667337; c=relaxed/simple; bh=rpAXRvqtwxU1XWUvQl/r9yjpM9n3xJzv6pB0r0+Kbx4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=qk+S8VRWs6Qasaz8JBdj2W0SqvGV94P5l1kCLli/DMyX2uKZmLb/bSjyHWBtjwFsxWIEvyw+XIylnEw9k39oR8v98NHu3zp1PIlhaK8Zjd0npRc+PaBaTguQGMzEWvFeWPf8k1iEL9J2armjk0D/Wa7bUGZotYTqnNsbAba5EqE= 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=mZtHF/+X; arc=none smtp.client-ip=91.218.175.186 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="mZtHF/+X" 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=1723667333; 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=8pUIHp5n0Uar92kH9etH8g4haQHVbq2z8GQwWBMKVbI=; b=mZtHF/+X+qPTZcKMFtclAXikUnNlfUnwTEG4tmMmgOnlawA/B7BHf93jTy2dB5PmVWzF+K 83+QCsTr39iKyFqluczw4EnCKNFyRrQSJyD9+RRQwFrUxEWYBb5TLwf3MV28ldF0WzTUtH Y0QfkRW+ayHV894fjUUljDs+3fwec5w= From: Shakeel Butt To: Andrew Morton Cc: Johannes Weiner , Michal Hocko , Roman Gushchin , Muchun Song , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Meta kernel team , cgroups@vger.kernel.org Subject: [PATCH 2/4] memcg: initiate deprecation of v1 soft limit Date: Wed, 14 Aug 2024 13:28:23 -0700 Message-ID: <20240814202825.2694077-3-shakeel.butt@linux.dev> In-Reply-To: <20240814202825.2694077-1-shakeel.butt@linux.dev> References: <20240814202825.2694077-1-shakeel.butt@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" Memcg v1 provides soft limit functionality for the best effort memory sharing between multiple workloads on a system. It is usually triggered through kswapd and at the moment does not reclaim kernel memory. Memcg v2 provide more straightforward best effort (memory.low) and hard protection (memory.min) functionalities. Let's initiate the deprecation of soft limit from v1 and gather if v2 needs something more to move the existing v1 users to v2 regarding soft limit. Signed-off-by: Shakeel Butt --- Documentation/admin-guide/cgroup-v1/memory.rst | 8 ++++++-- mm/memcontrol-v1.c | 3 +++ 2 files changed, 9 insertions(+), 2 deletions(-) diff --git a/Documentation/admin-guide/cgroup-v1/memory.rst b/Documentation= /admin-guide/cgroup-v1/memory.rst index fb6d3e2a6395..afe5e95e9f7b 100644 --- a/Documentation/admin-guide/cgroup-v1/memory.rst +++ b/Documentation/admin-guide/cgroup-v1/memory.rst @@ -78,6 +78,8 @@ Brief summary of control files. memory.memsw.max_usage_in_bytes show max memory+Swap usage recorded memory.soft_limit_in_bytes set/show soft limit of memory usage This knob is not available on CONFIG_PREEMPT_RT systems. + This knob is deprecated and shouldn't= be + used. memory.stat show various statistics memory.use_hierarchy set/show hierarchical account enabled This knob is deprecated and shouldn't= be @@ -701,8 +703,10 @@ For compatibility reasons writing 1 to memory.use_hier= archy will always pass:: =20 # echo 1 > memory.use_hierarchy =20 -7. Soft limits -=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D +7. Soft limits (DEPRECATED) +=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D + +THIS IS DEPRECATED! =20 Soft limits allow for greater sharing of memory. The idea behind soft limi= ts is to allow control groups to use as much of the memory as needed, provided diff --git a/mm/memcontrol-v1.c b/mm/memcontrol-v1.c index b8e2ee454eaa..e0bb54e42011 100644 --- a/mm/memcontrol-v1.c +++ b/mm/memcontrol-v1.c @@ -2458,6 +2458,9 @@ static ssize_t mem_cgroup_write(struct kernfs_open_fi= le *of, if (IS_ENABLED(CONFIG_PREEMPT_RT)) { ret =3D -EOPNOTSUPP; } else { + pr_warn_once("soft_limit_in_bytes is deprecated and will be removed. " + "Please report your usecase to linux-mm@kvack.org if you " + "depend on this functionality.\n"); WRITE_ONCE(memcg->soft_limit, nr_pages); ret =3D 0; } --=20 2.43.5 From nobody Sun Feb 8 01:30:34 2026 Received: from out-172.mta0.migadu.com (out-172.mta0.migadu.com [91.218.175.172]) (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 571CF1C688B for ; Wed, 14 Aug 2024 20:29:00 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.172 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723667342; cv=none; b=iUtyHc6NexWkypxjnyB+8DtJzv1XfP1pcoIpBK5C5s0ScslQ4pplxIV07rEl38zraclKMTYvkqDu+MZqPv1CUfLlpo2RCW3hDAbasKEUJ2CwJmX7vJfx3gz6kPg6eaNkG9OFWR6EJ1QaxnzOI5/dAXXFEZmjTCgq45PmkyJ8xQ8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723667342; c=relaxed/simple; bh=WZrqqayGdHruKCu2ZwbREPeaB65zaDXSWWVn3cpVHRA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=sQV9LQJHfwSOfWmzM15woLSfDkQZR+FBTbZw/yLDfwzzfumMJdIMqzSjGN2B4NXMw3IYfskKjMJ18EhpYI4TIDLgV7Z0nx99VIGs04fJyuqxhON56kiV4TQ7HvyDMTMWcmPsLfvJ0omDf0MamDusCkKkC907pnJUw7E52zUaYRY= 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=RTxI/hF6; arc=none smtp.client-ip=91.218.175.172 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="RTxI/hF6" 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=1723667338; 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=+6nvSZOz9QE0QcmtJItvdiDiC1dkEI/UgvNP1v9wjb4=; b=RTxI/hF6U5aR5/x110KhdXByEqtBRQLDxyno0Bp2FH/8UaaMMtMvvQUEcE747xNGGj5ZAr Tzu6Y4xh7inGaVCiMWkjcaY2vnpDJ60HeDDaEXrgiX/nSjlgUooZ3qit0CZUAmseLcoV7m LRpmuCJdmOrvK95RxEn3g3Y/WyXoLRk= From: Shakeel Butt To: Andrew Morton Cc: Johannes Weiner , Michal Hocko , Roman Gushchin , Muchun Song , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Meta kernel team , cgroups@vger.kernel.org Subject: [PATCH 3/4] memcg: initiate deprecation of oom_control Date: Wed, 14 Aug 2024 13:28:24 -0700 Message-ID: <20240814202825.2694077-4-shakeel.butt@linux.dev> In-Reply-To: <20240814202825.2694077-1-shakeel.butt@linux.dev> References: <20240814202825.2694077-1-shakeel.butt@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" The oom_control provides functionality to disable memcg oom-killer, notifications on oom-kill and reading the stats regarding oom-kills. This interface was mainly introduced to provide functionality for userspace oom-killers. However it is not robust enough and only supports OOM handling in the page fault path. For v2, the users can use the combination of memory.events notifications and memory.high interface to provide userspace OOM-killing functionality. Let's start the deprecation process for v1 and gather the info on how the current users are using this interface and work on providing a more robust functionality in v2. Signed-off-by: Shakeel Butt --- Documentation/admin-guide/cgroup-v1/memory.rst | 8 ++++++-- mm/memcontrol-v1.c | 7 +++++++ 2 files changed, 13 insertions(+), 2 deletions(-) diff --git a/Documentation/admin-guide/cgroup-v1/memory.rst b/Documentation= /admin-guide/cgroup-v1/memory.rst index afe5e95e9f7b..74cea6712d06 100644 --- a/Documentation/admin-guide/cgroup-v1/memory.rst +++ b/Documentation/admin-guide/cgroup-v1/memory.rst @@ -92,6 +92,8 @@ Brief summary of control files. This knob is deprecated and shouldn't= be used. memory.oom_control set/show oom controls. + This knob is deprecated and shouldn't= be + used. memory.numa_stat show the number of memory usage per numa node memory.kmem.limit_in_bytes Deprecated knob to set and read the k= ernel @@ -846,8 +848,10 @@ It's applicable for root and non-root cgroup. =20 .. _cgroup-v1-memory-oom-control: =20 -10. OOM Control -=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D +10. OOM Control (DEPRECATED) +=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D + +THIS IS DEPRECATED! =20 memory.oom_control file is for OOM notification and other controls. =20 diff --git a/mm/memcontrol-v1.c b/mm/memcontrol-v1.c index e0bb54e42011..07343e338e4e 100644 --- a/mm/memcontrol-v1.c +++ b/mm/memcontrol-v1.c @@ -1907,6 +1907,9 @@ static ssize_t memcg_write_event_control(struct kernf= s_open_file *of, event->register_event =3D mem_cgroup_usage_register_event; event->unregister_event =3D mem_cgroup_usage_unregister_event; } else if (!strcmp(name, "memory.oom_control")) { + pr_warn_once("oom_control is deprecated and will be removed. " + "Please report your usecase to linux-mm-@kvack.org" + " if you depend on this functionality. \n"; event->register_event =3D mem_cgroup_oom_register_event; event->unregister_event =3D mem_cgroup_oom_unregister_event; } else if (!strcmp(name, "memory.pressure_level")) { @@ -2754,6 +2757,10 @@ static int mem_cgroup_oom_control_write(struct cgrou= p_subsys_state *css, { struct mem_cgroup *memcg =3D mem_cgroup_from_css(css); =20 + pr_warn_once("oom_control is deprecated and will be removed. " + "Please report your usecase to linux-mm-@kvack.org if you " + "depend on this functionality. \n"; + /* cannot set to root cgroup and only 0 and 1 are allowed */ if (mem_cgroup_is_root(memcg) || !((val =3D=3D 0) || (val =3D=3D 1))) return -EINVAL; --=20 2.43.5 From nobody Sun Feb 8 01:30:34 2026 Received: from out-173.mta1.migadu.com (out-173.mta1.migadu.com [95.215.58.173]) (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 6E6A11C5787 for ; Wed, 14 Aug 2024 20:29:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.173 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723667350; cv=none; b=B+qfStkyE8F9Ve3AYeL8UBxrCbNqwicUl2YlzCTpmnzd9LNdpsA54cb+jxgEDyuu8Ipr0cTUa9gEliCEElNEe3cWrp+ldYLlBjeyqv/1L/M4elkqLhmd4qzpaRhwgmJlRAx7LrWoaraobvPDHisTL+rRMPoVbsFscktGROiNSXQ= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723667350; c=relaxed/simple; bh=ZxXKk8CRxRvsA2lfcJFJ4euvtuZOpZlA6H8+DVhUuoA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Ppgc1aMG63YiNp2BopfpgMWI6CQqZXZ0LnWo1L92UYOa2WJeGd26PEBSrtSBJYfRCcEi2cRhwHfo77xNfcfbPVCHKKgYFRgg3/Aq/5AiACjtjsi3TVm/gnLNmVGhorJoJ/R1FoUDTdhYcNF8Jm8r2rDWfHFy41trOLkyLeYsxm4= 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=uYIww40y; arc=none smtp.client-ip=95.215.58.173 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="uYIww40y" 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=1723667344; 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=3eCpg6JY4xdfuSX+uQFFlngNTZJeJ79jR/+n8cnnPGg=; b=uYIww40yZ2Xis6U+cV8wV/Qs15VdbFr767xvkUF6MKj22Z5GbZZ3gW76QyP813dZJJC4cN MmTNF4nMADLnjKP+viVJokLJazSp/Zr/b+oElSTlj+7+bo5blba50dZR8ER7c/fKvtdwrG 2YVGk1D8gSWKSpDZE6ngs16vo+I9uI4= From: Shakeel Butt To: Andrew Morton Cc: Johannes Weiner , Michal Hocko , Roman Gushchin , Muchun Song , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Meta kernel team , cgroups@vger.kernel.org Subject: [PATCH 4/4] memcg: initiate deprecation of pressure_level Date: Wed, 14 Aug 2024 13:28:25 -0700 Message-ID: <20240814202825.2694077-5-shakeel.butt@linux.dev> In-Reply-To: <20240814202825.2694077-1-shakeel.butt@linux.dev> References: <20240814202825.2694077-1-shakeel.butt@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" The pressure_level in memcg v1 provides memory pressure notifications to the user space. At the moment it provides notifications for three levels of memory pressure i.e. low, medium and critical, which are defined based on internal memory reclaim implementation details. More specifically the ratio or scanned and reclaimed pages during a memory reclaim. However this is not robust as there are workloads with mostly unreclaimable user memory or kernel memory. For v2, the users can use PSI for memory pressure status of the system or the cgroup. Let's start the deprecation process for pressure_level and add warnings to gather the info on how the current users are using this interface and how they can be used to PSI. Signed-off-by: Shakeel Butt --- Documentation/admin-guide/cgroup-v1/memory.rst | 8 ++++++-- mm/memcontrol-v1.c | 3 +++ 2 files changed, 9 insertions(+), 2 deletions(-) diff --git a/Documentation/admin-guide/cgroup-v1/memory.rst b/Documentation= /admin-guide/cgroup-v1/memory.rst index 74cea6712d06..8ec1faf08b6b 100644 --- a/Documentation/admin-guide/cgroup-v1/memory.rst +++ b/Documentation/admin-guide/cgroup-v1/memory.rst @@ -86,6 +86,8 @@ Brief summary of control files. used. memory.force_empty trigger forced page reclaim memory.pressure_level set memory pressure notifications + This knob is deprecated and shouldn't= be + used. memory.swappiness set/show swappiness parameter of vmscan (See sysctl's vm.swappiness) memory.move_charge_at_immigrate set/show controls of moving charges @@ -898,8 +900,10 @@ At reading, current status of OOM is shown. The number of processes belonging to this cgroup killed by any kind of OOM killer. =20 -11. Memory Pressure -=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D +11. Memory Pressure (DEPRECATED) +=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D + +THIS IS DEPRECATED! =20 The pressure level notifications can be used to monitor the memory allocation cost; based on the pressure, applications can implement diff --git a/mm/memcontrol-v1.c b/mm/memcontrol-v1.c index 07343e338e4e..420c7d15f12a 100644 --- a/mm/memcontrol-v1.c +++ b/mm/memcontrol-v1.c @@ -1913,6 +1913,9 @@ static ssize_t memcg_write_event_control(struct kernf= s_open_file *of, event->register_event =3D mem_cgroup_oom_register_event; event->unregister_event =3D mem_cgroup_oom_unregister_event; } else if (!strcmp(name, "memory.pressure_level")) { + pr_warn_once("pressure_level is deprecated and will be removed. " + "Please report your usecase to linux-mm-@kvack.org " + "if you depend on this functionality. \n"; event->register_event =3D vmpressure_register_event; event->unregister_event =3D vmpressure_unregister_event; } else if (!strcmp(name, "memory.memsw.usage_in_bytes")) { --=20 2.43.5