From patchwork Mon May 9 18:38:18 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Roman Gushchin X-Patchwork-Id: 12843972 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]) by smtp.lore.kernel.org (Postfix) with ESMTP id CEC4DC433F5 for ; Mon, 9 May 2022 18:38:42 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 65C476B007D; Mon, 9 May 2022 14:38:42 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 609E66B007E; Mon, 9 May 2022 14:38:42 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 4AD796B0080; Mon, 9 May 2022 14:38:42 -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 3C2736B007D for ; Mon, 9 May 2022 14:38:42 -0400 (EDT) Received: from smtpin21.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay02.hostedemail.com (Postfix) with ESMTP id 133C12FDD0 for ; Mon, 9 May 2022 18:38:42 +0000 (UTC) X-FDA: 79447065684.21.8F75CB6 Received: from out0.migadu.com (out0.migadu.com [94.23.1.103]) by imf16.hostedemail.com (Postfix) with ESMTP id 3F8891800B0 for ; Mon, 9 May 2022 18:38:33 +0000 (UTC) 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=1652121520; 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=7n7dZu7Y2U7vRxgiVDuS2aKmDH89wQvt+0LixtzJNwc=; b=X/nmv/5QYZdTAzGxptAD4HPoB18DvwQnGzxs6tocRwwWGHUwAf0dXoJv6HV36AZ2MRiLg5 delJvvKPQNEMK2y3q5GqoDzm/YJdiqd6IE5g7Y5r8IbHt0MsYBn15MdfhXHUYubKeL5k/W ezRjg1syyJ3GqACNqrZC1NSHYzwYSOA= From: Roman Gushchin To: Andrew Morton , linux-mm@kvack.org Cc: Dave Chinner , linux-kernel@vger.kernel.org, Kent Overstreet , Hillf Danton , Christophe JAILLET , Roman Gushchin Subject: [PATCH v3 4/6] mm: docs: document shrinker debugfs Date: Mon, 9 May 2022 11:38:18 -0700 Message-Id: <20220509183820.573666-5-roman.gushchin@linux.dev> In-Reply-To: <20220509183820.573666-1-roman.gushchin@linux.dev> References: <20220509183820.573666-1-roman.gushchin@linux.dev> MIME-Version: 1.0 X-Migadu-Flow: FLOW_OUT X-Migadu-Auth-User: linux.dev X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 3F8891800B0 X-Stat-Signature: o8ndjfqnb1rfdscfr4kzz4dm3yj5j7f3 X-Rspam-User: Authentication-Results: imf16.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b="X/nmv/5Q"; spf=pass (imf16.hostedemail.com: domain of roman.gushchin@linux.dev designates 94.23.1.103 as permitted sender) smtp.mailfrom=roman.gushchin@linux.dev; dmarc=pass (policy=none) header.from=linux.dev X-HE-Tag: 1652121513-774434 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: Add a document describing the shrinker debugfs interface. Signed-off-by: Roman Gushchin --- Documentation/admin-guide/mm/index.rst | 1 + .../admin-guide/mm/shrinker_debugfs.rst | 100 ++++++++++++++++++ 2 files changed, 101 insertions(+) create mode 100644 Documentation/admin-guide/mm/shrinker_debugfs.rst diff --git a/Documentation/admin-guide/mm/index.rst b/Documentation/admin-guide/mm/index.rst index c21b5823f126..1bd11118dfb1 100644 --- a/Documentation/admin-guide/mm/index.rst +++ b/Documentation/admin-guide/mm/index.rst @@ -36,6 +36,7 @@ the Linux memory management. numa_memory_policy numaperf pagemap + shrinker_debugfs soft-dirty swap_numa transhuge diff --git a/Documentation/admin-guide/mm/shrinker_debugfs.rst b/Documentation/admin-guide/mm/shrinker_debugfs.rst new file mode 100644 index 000000000000..6783f8190e63 --- /dev/null +++ b/Documentation/admin-guide/mm/shrinker_debugfs.rst @@ -0,0 +1,100 @@ +.. _shrinker_debugfs: + +========================== +Shrinker Debugfs Interface +========================== + +Shrinker debugfs interface provides a visibility into the kernel memory +shrinkers subsystem and allows to get information about individual shrinkers. + +For each shrinker registered in the system a directory in **/shrinker/** +is created. The directory's name is composed from the shrinker's name and an +unique id: e.g. *kfree_rcu-0* or *sb-xfs:vda1-36*. + +Each shrinker directory contains the **count** file, which allows to trigger +the *count_objects()* callback for each memcg and numa node (if applicable). + +Usage: +------ + +1. *List registered shrinkers* + + :: + + $ cd /sys/kernel/debug/shrinker/ + $ ls + dqcache-16 sb-hugetlbfs-17 sb-rootfs-2 sb-tmpfs-50 + kfree_rcu-0 sb-hugetlbfs-33 sb-securityfs-6 sb-tracefs-13 + sb-aio-20 sb-iomem-12 sb-selinuxfs-22 sb-xfs:vda1-36 + sb-anon_inodefs-15 sb-mqueue-21 sb-sockfs-8 sb-zsmalloc-19 + sb-bdev-3 sb-nsfs-4 sb-sysfs-26 shadow-18 + sb-bpf-32 sb-pipefs-14 sb-tmpfs-1 thp_deferred_split-10 + sb-btrfs:vda2-24 sb-proc-25 sb-tmpfs-27 thp_zero-9 + sb-cgroup2-30 sb-proc-39 sb-tmpfs-29 xfs_buf-37 + sb-configfs-23 sb-proc-41 sb-tmpfs-35 xfs_inodegc-38 + sb-dax-11 sb-proc-45 sb-tmpfs-40 zspool-34 + sb-debugfs-7 sb-proc-46 sb-tmpfs-42 + sb-devpts-28 sb-proc-47 sb-tmpfs-43 + sb-devtmpfs-5 sb-pstore-31 sb-tmpfs-44 + +2. *Get information about a specific shrinker* + + :: + + $ cd sb-btrfs\:vda2-24/ + $ ls + count + +3. *Count objects* + + Each line in the output has the following format:: + + ... + ... + ... + + If there are no objects on all numa nodes, a line is omitted. If there + are no objects at all, the output might be empty. + :: + + $ cat count + 1 224 2 + 21 98 0 + 55 818 10 + 2367 2 0 + 2401 30 0 + 225 13 0 + 599 35 0 + 939 124 0 + 1041 3 0 + 1075 1 0 + 1109 1 0 + 1279 60 0 + 1313 7 0 + 1347 39 0 + 1381 3 0 + 1449 14 0 + 1483 63 0 + 1517 53 0 + 1551 6 0 + 1585 1 0 + 1619 6 0 + 1653 40 0 + 1687 11 0 + 1721 8 0 + 1755 4 0 + 1789 52 0 + 1823 888 0 + 1857 1 0 + 1925 2 0 + 1959 32 0 + 2027 22 0 + 2061 9 0 + 2469 799 0 + 2537 861 0 + 2639 1 0 + 2707 70 0 + 2775 4 0 + 2877 84 0 + 293 1 0 + 735 8 0