From patchwork Tue Oct 19 15:34:08 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Shakeel Butt X-Patchwork-Id: 12570413 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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C89CEC4332F for ; Tue, 19 Oct 2021 15:34:23 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 5664761074 for ; Tue, 19 Oct 2021 15:34:23 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 5664761074 Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvack.org Received: by kanga.kvack.org (Postfix) id BCF7B900004; Tue, 19 Oct 2021 11:34:22 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id B5626900002; Tue, 19 Oct 2021 11:34:22 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 9D007900004; Tue, 19 Oct 2021 11:34:22 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0232.hostedemail.com [216.40.44.232]) by kanga.kvack.org (Postfix) with ESMTP id 87AB5900002 for ; Tue, 19 Oct 2021 11:34:22 -0400 (EDT) Received: from smtpin16.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 272EA3A7C4 for ; Tue, 19 Oct 2021 15:34:22 +0000 (UTC) X-FDA: 78713583564.16.319C419 Received: from mail-pf1-f201.google.com (mail-pf1-f201.google.com [209.85.210.201]) by imf11.hostedemail.com (Postfix) with ESMTP id DAA71F0000A8 for ; Tue, 19 Oct 2021 15:34:21 +0000 (UTC) Received: by mail-pf1-f201.google.com with SMTP id m26-20020a62a21a000000b0041361973ba7so140170pff.15 for ; Tue, 19 Oct 2021 08:34:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:message-id:mime-version:subject:from:to:cc; bh=b4zuBMQ6rB3BJhMbiTI+bHBlQbKmGojFin0ETDqCqgs=; b=rFMa8vwet/lkvToH0oW1p+K5cFqa7WZrolQyzwr5vqQX//r/Z65baLysr7T2GaQULv 8oJpbjYqV+ZCU+f10JFaYReHzKzhhZMU97gcW/GVrw0J8EMgaRITnTZ+aDP3YD2jzivp bFdR3kTffPL94z08NhW7pOPcUf/BaP2+SVGmhUUMzQa4d8rtdoIHuxUUl7t4Y/MM6bND EOPoxl6N3Yn+nPGBCM68QnnxI1FaOgkfjOS21e7UQtf8kEOiEpa1fC3pm11DahghiWu2 EYOjMMffkS3e9gi+9DLre4UUmxC4X9vAJLvcmd/cX2GLBvCG7XLopZw5lF7JHX72a0il 3NKw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:message-id:mime-version:subject:from:to:cc; bh=b4zuBMQ6rB3BJhMbiTI+bHBlQbKmGojFin0ETDqCqgs=; b=g4WcSUZ7VGIM9pgCVxilCwkQ7DE2s1UuYInWywag7waikfkTG6jdt/iVeQNv1+q0Zw 7vmbzfGYlWVbdKwhARka3t+3NLSh/dFuUQjx5mXviBrFZyr83Vdu7o2SzGapLsUXcT+7 lDVONIQhbcHDb304k3If7Maultw788pNb8Ru8prEb2vySvxxJGSnNKXoTnYU3dWSbm5x T9lAGg2zaavFySgmfv8ymKyApILuFpb/beIxif6TAK8TTUl0CRjGNOXhRO/Na8RUQLys sIUCF5vfOyg5hL4u8CSrGHqs/NOjoLyOg8f/te5RtfZ/QXrv021BJw8+atJgqKzDcyHw NhRg== X-Gm-Message-State: AOAM531Kp5YKtyp3flm9nLq9ZtnXHUTx+hyAQppAuZPHXiEPSf1yoVYD mOFqkdI6ZDlSqiyhU2/rVZNjTEuMn6v+8w== X-Google-Smtp-Source: ABdhPJzz98WCn/tuXSCa52LIqDLVgmNtS4YTmeUTfl/rTTpuMN7stUpDc5QRcbsmesVGqSTReq6GbDy03xs1LQ== X-Received: from shakeelb.svl.corp.google.com ([2620:15c:2cd:202:6d48:cae4:d5cb:a596]) (user=shakeelb job=sendgmr) by 2002:a17:90b:1c06:: with SMTP id oc6mr660557pjb.204.1634657660555; Tue, 19 Oct 2021 08:34:20 -0700 (PDT) Date: Tue, 19 Oct 2021 08:34:08 -0700 Message-Id: <20211019153408.2916808-1-shakeelb@google.com> Mime-Version: 1.0 X-Mailer: git-send-email 2.33.0.1079.g6e70778dc9-goog Subject: [PATCH v3] memcg, kmem: further deprecate kmem.limit_in_bytes From: Shakeel Butt To: Johannes Weiner , Michal Hocko Cc: Vasily Averin , Roman Gushchin , Andrew Morton , cgroups@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Shakeel Butt , Michal Hocko , Muchun Song Authentication-Results: imf11.hostedemail.com; dkim=pass header.d=google.com header.s=20210112 header.b=rFMa8vwe; dmarc=pass (policy=reject) header.from=google.com; spf=pass (imf11.hostedemail.com: domain of 3fOVuYQgKCBUD2v5zz6w19916z.x97638FI-775Gvx5.9C1@flex--shakeelb.bounces.google.com designates 209.85.210.201 as permitted sender) smtp.mailfrom=3fOVuYQgKCBUD2v5zz6w19916z.x97638FI-775Gvx5.9C1@flex--shakeelb.bounces.google.com X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: DAA71F0000A8 X-Stat-Signature: qm1jcyh5wsfpmyuzoqwagiid9cxwdtfh X-HE-Tag: 1634657661-603426 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: The deprecation process of kmem.limit_in_bytes started with the commit 0158115f702 ("memcg, kmem: deprecate kmem.limit_in_bytes") which also explains in detail the motivation behind the deprecation. To summarize, it is the unexpected behavior on hitting the kmem limit. This patch moves the deprecation process to the next stage by disallowing to set the kmem limit. In future we might just remove the kmem.limit_in_bytes file completely. Signed-off-by: Shakeel Butt Acked-by: Roman Gushchin Acked-by: Michal Hocko Reviewed-by: Muchun Song Cc: Vasily Averin Cc: Johannes Weiner Cc: Andrew Morton --- Changes since v2: - Updated the documentation Changes since v1: - Replaced EINVAL with ENOTSUPP on setting kmem limits. - V1 was posted last year at [0]. [0] https://lore.kernel.org/all/20201118175726.2453120-1-shakeelb@google.com/ .../admin-guide/cgroup-v1/memory.rst | 11 ++---- mm/memcontrol.c | 35 +++---------------- 2 files changed, 6 insertions(+), 40 deletions(-) diff --git a/Documentation/admin-guide/cgroup-v1/memory.rst b/Documentation/admin-guide/cgroup-v1/memory.rst index 41191b5fb69d..faac50149a22 100644 --- a/Documentation/admin-guide/cgroup-v1/memory.rst +++ b/Documentation/admin-guide/cgroup-v1/memory.rst @@ -87,10 +87,8 @@ Brief summary of control files. memory.oom_control set/show oom controls. memory.numa_stat show the number of memory usage per numa node - memory.kmem.limit_in_bytes set/show hard limit for kernel memory - This knob is deprecated and shouldn't be - used. It is planned that this be removed in - the foreseeable future. + memory.kmem.limit_in_bytes This knob is deprecated and writing to + it will return -ENOTSUPP. memory.kmem.usage_in_bytes show current kernel memory allocation memory.kmem.failcnt show the number of kernel memory usage hits limits @@ -518,11 +516,6 @@ will be charged as a new owner of it. charged file caches. Some out-of-use page caches may keep charged until memory pressure happens. If you want to avoid that, force_empty will be useful. - Also, note that when memory.kmem.limit_in_bytes is set the charges due to - kernel pages will still be seen. This is not considered a failure and the - write will still return success. In this case, it is expected that - memory.kmem.usage_in_bytes == memory.usage_in_bytes. - 5.2 stat file ------------- diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 8f1d9c028897..49a76049a885 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -2999,7 +2999,6 @@ static void obj_cgroup_uncharge_pages(struct obj_cgroup *objcg, static int obj_cgroup_charge_pages(struct obj_cgroup *objcg, gfp_t gfp, unsigned int nr_pages) { - struct page_counter *counter; struct mem_cgroup *memcg; int ret; @@ -3009,21 +3008,8 @@ static int obj_cgroup_charge_pages(struct obj_cgroup *objcg, gfp_t gfp, if (ret) goto out; - if (!cgroup_subsys_on_dfl(memory_cgrp_subsys) && - !page_counter_try_charge(&memcg->kmem, nr_pages, &counter)) { - - /* - * Enforce __GFP_NOFAIL allocation because callers are not - * prepared to see failures and likely do not have any failure - * handling code. - */ - if (gfp & __GFP_NOFAIL) { - page_counter_charge(&memcg->kmem, nr_pages); - goto out; - } - cancel_charge(memcg, nr_pages); - ret = -ENOMEM; - } + if (!cgroup_subsys_on_dfl(memory_cgrp_subsys)) + page_counter_charge(&memcg->kmem, nr_pages); out: css_put(&memcg->css); @@ -3715,17 +3701,6 @@ static void memcg_offline_kmem(struct mem_cgroup *memcg) } #endif /* CONFIG_MEMCG_KMEM */ -static int memcg_update_kmem_max(struct mem_cgroup *memcg, - unsigned long max) -{ - int ret; - - mutex_lock(&memcg_max_mutex); - ret = page_counter_set_max(&memcg->kmem, max); - mutex_unlock(&memcg_max_mutex); - return ret; -} - static int memcg_update_tcp_max(struct mem_cgroup *memcg, unsigned long max) { int ret; @@ -3791,10 +3766,8 @@ static ssize_t mem_cgroup_write(struct kernfs_open_file *of, ret = mem_cgroup_resize_max(memcg, nr_pages, true); break; case _KMEM: - pr_warn_once("kmem.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 = memcg_update_kmem_max(memcg, nr_pages); + /* kmem.limit_in_bytes is deprecated. */ + ret = -ENOTSUPP; break; case _TCP: ret = memcg_update_tcp_max(memcg, nr_pages);