From patchwork Wed May 25 20:25:54 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Roman Gushchin X-Patchwork-Id: 12861707 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 58C82C433EF for ; Wed, 25 May 2022 20:26:16 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 8AB5E8D0003; Wed, 25 May 2022 16:26:15 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 833FC8D0001; Wed, 25 May 2022 16:26:15 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 6FCBF8D0003; Wed, 25 May 2022 16:26:15 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id 5CAEB8D0001 for ; Wed, 25 May 2022 16:26:15 -0400 (EDT) Received: from smtpin04.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id 2CE932162D for ; Wed, 25 May 2022 20:26:15 +0000 (UTC) X-FDA: 79505397510.04.FBA1D6C Received: from out1.migadu.com (out1.migadu.com [91.121.223.63]) by imf02.hostedemail.com (Postfix) with ESMTP id 3EA8580020 for ; Wed, 25 May 2022 20:26:11 +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=1653510372; 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; bh=2ZlGvzSBFG6qdsjV0vKLyG494pe1Nox24RKHRC8tAOU=; b=ncpjFVQTc5Hefj4NU6ixKjlKsoWpz4vxxdQg+7LXQJfloR2HdiAVIpsWDwsbbw8Z5IqQVa FKd+SeLHOl/VfvBLKlpHjIuCPN/syKj+IqX3fA4gR8/vGoqq4R0xQPMLdT5HIO9oTCBui/ BFcIiaGJkwuKgChRPiE3vTWXRAaoJUo= From: Roman Gushchin To: Andrew Morton , linux-mm@kvack.org Cc: Dave Chinner , linux-kernel@vger.kernel.org, Kent Overstreet , Hillf Danton , Christophe JAILLET , Muchun Song , Roman Gushchin Subject: [PATCH v4 0/6] mm: introduce shrinker debugfs interface Date: Wed, 25 May 2022 13:25:54 -0700 Message-Id: <20220525202600.2910982-1-roman.gushchin@linux.dev> MIME-Version: 1.0 X-Migadu-Flow: FLOW_OUT X-Migadu-Auth-User: linux.dev X-Stat-Signature: k7oku1rhtmts4kgr1r3iqfn1sckcfmth X-Rspam-User: Authentication-Results: imf02.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=ncpjFVQT; dmarc=pass (policy=none) header.from=linux.dev; spf=pass (imf02.hostedemail.com: domain of roman.gushchin@linux.dev designates 91.121.223.63 as permitted sender) smtp.mailfrom=roman.gushchin@linux.dev X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: 3EA8580020 X-HE-Tag: 1653510371-755399 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 only existing debugging mechanism is a couple of tracepoints in do_shrink_slab(): mm_shrink_slab_start and mm_shrink_slab_end. They aren't covering everything though: shrinkers which report 0 objects will never show up, there is no support for memcg-aware shrinkers. Shrinkers are identified by their scan function, which is not always enough (e.g. hard to guess which super block's shrinker it is having only "super_cache_scan"). To provide a better visibility and debug options for memory shrinkers this patchset introduces a /sys/kernel/debug/shrinker interface, to some extent similar to /sys/kernel/slab. For each shrinker registered in the system a directory is created. As now, the directory will contain only a "scan" file, which allows to get the number of managed objects for each memory cgroup (for memcg-aware shrinkers) and each numa node (for numa-aware shrinkers on a numa machine). Other interfaces might be added in the future. To make debugging more pleasant, the patchset also names all shrinkers, so that debugfs entries can have meaningful names. v4: 1) multiple shrinkers naming enhancements, by Kent and Dave 2) multiple minor fixes/optimizations, by Muchun v3: 1) separated the "scan" part into a separate patch, by Dave 2) merged *_memcg, *_node and *_memcg_node interfaces, by Dave 3) shrinkers naming enhancements, by Christophe and Dave 4) added signal_pending() check, by Hillf 5) enabled by default, by Dave v2: 1) switched to debugfs, suggested by Mike, Andrew, Greg and others 2) switched to seq_file API for output, no PAGE_SIZE limit anymore, by Andrew 3) switched to down_read_killable(), suggested by Hillf 4) dropped stateful filtering and "freed" returning, by Kent 5) added docs, by Andrew 6) added memcg_shrinker.py tool rfc: https://lwn.net/Articles/891542/ Roman Gushchin (6): mm: memcontrol: introduce mem_cgroup_ino() and mem_cgroup_get_from_ino() mm: shrinkers: introduce debugfs interface for memory shrinkers mm: shrinkers: provide shrinkers with names mm: docs: document shrinker debugfs tools: add memcg_shrinker.py mm: shrinkers: add scan interface for shrinker debugfs Documentation/admin-guide/mm/index.rst | 1 + .../admin-guide/mm/shrinker_debugfs.rst | 131 ++++++++ arch/x86/kvm/mmu/mmu.c | 2 +- drivers/android/binder_alloc.c | 2 +- drivers/gpu/drm/i915/gem/i915_gem_shrinker.c | 3 +- drivers/gpu/drm/msm/msm_gem_shrinker.c | 2 +- .../gpu/drm/panfrost/panfrost_gem_shrinker.c | 2 +- drivers/gpu/drm/ttm/ttm_pool.c | 2 +- drivers/md/bcache/btree.c | 2 +- drivers/md/dm-bufio.c | 3 +- drivers/md/dm-zoned-metadata.c | 4 +- drivers/md/raid5.c | 2 +- drivers/misc/vmw_balloon.c | 2 +- drivers/virtio/virtio_balloon.c | 2 +- drivers/xen/xenbus/xenbus_probe_backend.c | 2 +- fs/btrfs/super.c | 2 + fs/erofs/utils.c | 2 +- fs/ext4/extents_status.c | 3 +- fs/f2fs/super.c | 2 +- fs/gfs2/glock.c | 2 +- fs/gfs2/main.c | 2 +- fs/jbd2/journal.c | 3 +- fs/mbcache.c | 2 +- fs/nfs/nfs42xattr.c | 7 +- fs/nfs/super.c | 2 +- fs/nfsd/filecache.c | 2 +- fs/nfsd/nfscache.c | 3 +- fs/quota/dquot.c | 2 +- fs/super.c | 6 +- fs/ubifs/super.c | 2 +- fs/xfs/xfs_buf.c | 3 +- fs/xfs/xfs_icache.c | 2 +- fs/xfs/xfs_qm.c | 3 +- include/linux/memcontrol.h | 21 ++ include/linux/shrinker.h | 31 +- kernel/rcu/tree.c | 2 +- lib/Kconfig.debug | 9 + mm/Makefile | 1 + mm/huge_memory.c | 4 +- mm/memcontrol.c | 23 ++ mm/shrinker_debug.c | 285 ++++++++++++++++++ mm/vmscan.c | 64 +++- mm/workingset.c | 2 +- mm/zsmalloc.c | 3 +- net/sunrpc/auth.c | 2 +- tools/cgroup/memcg_shrinker.py | 71 +++++ 46 files changed, 684 insertions(+), 46 deletions(-) create mode 100644 Documentation/admin-guide/mm/shrinker_debugfs.rst create mode 100644 mm/shrinker_debug.c create mode 100755 tools/cgroup/memcg_shrinker.py