From patchwork Mon Jul 24 09:43:10 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Qi Zheng X-Patchwork-Id: 705814 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 22C76C001DF for ; Mon, 24 Jul 2023 09:46:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232270AbjGXJqs (ORCPT ); Mon, 24 Jul 2023 05:46:48 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46616 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229973AbjGXJqX (ORCPT ); Mon, 24 Jul 2023 05:46:23 -0400 Received: from mail-pl1-x62c.google.com (mail-pl1-x62c.google.com [IPv6:2607:f8b0:4864:20::62c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5B3DAE7B for ; Mon, 24 Jul 2023 02:45:43 -0700 (PDT) Received: by mail-pl1-x62c.google.com with SMTP id d9443c01a7336-1bba9539a23so640055ad.1 for ; Mon, 24 Jul 2023 02:45:43 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance.com; s=google; t=1690191943; x=1690796743; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=DaxJS65ntPERL7le+nmtmDDoPHIKL7Svp/IgETL6ZeE=; b=bsUNhBCXwNUzkDR0ZBYGRWY6QU8jf6SXW0GNGt2FOx6GMmf4JYDUwOhZCN0a9aNwPh pTka7+wy4J6SiQlycedqXCWLDNsWz3aJioSMhFKKX+Cimy7bU+oF7hjqxyvShR8A2yEG Bu7LESrzTJZCH9TPtc2I9FzALspZlYdCLyw0Gn9itfPl/wiIrNjf25JL50bsQdJ04tcL SlbyOamKluDXUz4pmzuKSCdYj+rqtmnfikA7iqukCNA9GBpbd9F7GXY8//WwnDt8lif7 VBbsqb4LU2WF81b1loSTallposIksCkIrM7zY2O8grvdOy/OC2xy9l8uFRAuNMFBjkRJ /Eug== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1690191943; x=1690796743; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=DaxJS65ntPERL7le+nmtmDDoPHIKL7Svp/IgETL6ZeE=; b=MRMm8tZZusLbsK2GIvR/9xsmixOcieOeN/jBfeWhNNx/r3ZkgP38agVkwzKC9Z28WF bZvsv6D4cLeUKr9z1ULIp5FHaO6etp0fOwfG9cdekULkFdlVUSzyPNCddbYG1/FDQuQx xvI3xccnIE474WkttBTBSMzecJNxqM4yjAZRaHI5Fo9fucKuqEvflizKh9iuJMM10B+R UQ233YcJZl7ufUlUzS57tl+pPa9BCzGQAQTu/IsBQe6jdrdIalI0opu8ORlX5xsu5Z3x S1zouzBGrSawH6rput3IwdOQdo4NwJhv2zX+3DVyY62hrYG5lqtEHrY0Brljxlfhyycl eIUg== X-Gm-Message-State: ABy/qLZZEDMwly3QuWxBa4b4nY/1kJZg9W+R4AzDdOR4p6XAgqbh16c2 xbpb9inhWQ6LJ3WgiU05o9pYQQ== X-Google-Smtp-Source: APBJJlGWwe+Wn5SAE9CC225imGBvK3oJNP2MQHqUiC6fnoUxBGqj3ofPftHC2Yw9p8SUIC56L+2IOQ== X-Received: by 2002:a17:903:2305:b0:1b8:b0c4:2e3d with SMTP id d5-20020a170903230500b001b8b0c42e3dmr12236473plh.4.1690191942806; Mon, 24 Jul 2023 02:45:42 -0700 (PDT) Received: from C02DW0BEMD6R.bytedance.net ([203.208.167.147]) by smtp.gmail.com with ESMTPSA id d5-20020a170902c18500b001bb20380bf2sm8467233pld.13.2023.07.24.02.45.31 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 24 Jul 2023 02:45:42 -0700 (PDT) From: Qi Zheng To: akpm@linux-foundation.org, david@fromorbit.com, tkhai@ya.ru, vbabka@suse.cz, roman.gushchin@linux.dev, djwong@kernel.org, brauner@kernel.org, paulmck@kernel.org, tytso@mit.edu, steven.price@arm.com, cel@kernel.org, senozhatsky@chromium.org, yujie.liu@intel.com, gregkh@linuxfoundation.org, muchun.song@linux.dev Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, x86@kernel.org, kvm@vger.kernel.org, xen-devel@lists.xenproject.org, linux-erofs@lists.ozlabs.org, linux-f2fs-devel@lists.sourceforge.net, cluster-devel@redhat.com, linux-nfs@vger.kernel.org, linux-mtd@lists.infradead.org, rcu@vger.kernel.org, netdev@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-arm-msm@vger.kernel.org, dm-devel@redhat.com, linux-raid@vger.kernel.org, linux-bcache@vger.kernel.org, virtualization@lists.linux-foundation.org, linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org, linux-xfs@vger.kernel.org, linux-btrfs@vger.kernel.org, Qi Zheng Subject: [PATCH v2 03/47] mm: shrinker: add infrastructure for dynamically allocating shrinker Date: Mon, 24 Jul 2023 17:43:10 +0800 Message-Id: <20230724094354.90817-4-zhengqi.arch@bytedance.com> X-Mailer: git-send-email 2.24.3 (Apple Git-128) In-Reply-To: <20230724094354.90817-1-zhengqi.arch@bytedance.com> References: <20230724094354.90817-1-zhengqi.arch@bytedance.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org Currently, the shrinker instances can be divided into the following three types: a) global shrinker instance statically defined in the kernel, such as workingset_shadow_shrinker. b) global shrinker instance statically defined in the kernel modules, such as mmu_shrinker in x86. c) shrinker instance embedded in other structures. For case a, the memory of shrinker instance is never freed. For case b, the memory of shrinker instance will be freed after synchronize_rcu() when the module is unloaded. For case c, the memory of shrinker instance will be freed along with the structure it is embedded in. In preparation for implementing lockless slab shrink, we need to dynamically allocate those shrinker instances in case c, then the memory can be dynamically freed alone by calling kfree_rcu(). So this commit adds the following new APIs for dynamically allocating shrinker, and add a private_data field to struct shrinker to record and get the original embedded structure. 1. shrinker_alloc() Used to allocate shrinker instance itself and related memory, it will return a pointer to the shrinker instance on success and NULL on failure. 2. shrinker_free_non_registered() Used to destroy the non-registered shrinker instance. 3. shrinker_register() Used to register the shrinker instance, which is same as the current register_shrinker_prepared(). 4. shrinker_unregister() Used to unregister and free the shrinker instance. In order to simplify shrinker-related APIs and make shrinker more independent of other kernel mechanisms, subsequent submissions will use the above API to convert all shrinkers (including case a and b) to dynamically allocated, and then remove all existing APIs. This will also have another advantage mentioned by Dave Chinner: ``` The other advantage of this is that it will break all the existing out of tree code and third party modules using the old API and will no longer work with a kernel using lockless slab shrinkers. They need to break (both at the source and binary levels) to stop bad things from happening due to using uncoverted shrinkers in the new setup. ``` Signed-off-by: Qi Zheng --- include/linux/shrinker.h | 6 +++ mm/shrinker.c | 113 +++++++++++++++++++++++++++++++++++++++ 2 files changed, 119 insertions(+) diff --git a/include/linux/shrinker.h b/include/linux/shrinker.h index 961cb84e51f5..296f5e163861 100644 --- a/include/linux/shrinker.h +++ b/include/linux/shrinker.h @@ -70,6 +70,8 @@ struct shrinker { int seeks; /* seeks to recreate an obj */ unsigned flags; + void *private_data; + /* These are for internal use */ struct list_head list; #ifdef CONFIG_MEMCG @@ -98,6 +100,10 @@ struct shrinker { unsigned long shrink_slab(gfp_t gfp_mask, int nid, struct mem_cgroup *memcg, int priority); +struct shrinker *shrinker_alloc(unsigned int flags, const char *fmt, ...); +void shrinker_free_non_registered(struct shrinker *shrinker); +void shrinker_register(struct shrinker *shrinker); +void shrinker_unregister(struct shrinker *shrinker); extern int __printf(2, 3) prealloc_shrinker(struct shrinker *shrinker, const char *fmt, ...); diff --git a/mm/shrinker.c b/mm/shrinker.c index 0a32ef42f2a7..d820e4cc5806 100644 --- a/mm/shrinker.c +++ b/mm/shrinker.c @@ -548,6 +548,119 @@ unsigned long shrink_slab(gfp_t gfp_mask, int nid, struct mem_cgroup *memcg, return freed; } +struct shrinker *shrinker_alloc(unsigned int flags, const char *fmt, ...) +{ + struct shrinker *shrinker; + unsigned int size; + va_list __maybe_unused ap; + int err; + + shrinker = kzalloc(sizeof(struct shrinker), GFP_KERNEL); + if (!shrinker) + return NULL; + +#ifdef CONFIG_SHRINKER_DEBUG + va_start(ap, fmt); + shrinker->name = kvasprintf_const(GFP_KERNEL, fmt, ap); + va_end(ap); + if (!shrinker->name) + goto err_name; +#endif + shrinker->flags = flags; + + if (flags & SHRINKER_MEMCG_AWARE) { + err = prealloc_memcg_shrinker(shrinker); + if (err == -ENOSYS) + shrinker->flags &= ~SHRINKER_MEMCG_AWARE; + else if (err == 0) + goto done; + else + goto err_flags; + } + + /* + * The nr_deferred is available on per memcg level for memcg aware + * shrinkers, so only allocate nr_deferred in the following cases: + * - non memcg aware shrinkers + * - !CONFIG_MEMCG + * - memcg is disabled by kernel command line + */ + size = sizeof(*shrinker->nr_deferred); + if (flags & SHRINKER_NUMA_AWARE) + size *= nr_node_ids; + + shrinker->nr_deferred = kzalloc(size, GFP_KERNEL); + if (!shrinker->nr_deferred) + goto err_flags; + +done: + return shrinker; + +err_flags: +#ifdef CONFIG_SHRINKER_DEBUG + kfree_const(shrinker->name); + shrinker->name = NULL; +err_name: +#endif + kfree(shrinker); + return NULL; +} +EXPORT_SYMBOL(shrinker_alloc); + +void shrinker_free_non_registered(struct shrinker *shrinker) +{ +#ifdef CONFIG_SHRINKER_DEBUG + kfree_const(shrinker->name); + shrinker->name = NULL; +#endif + if (shrinker->flags & SHRINKER_MEMCG_AWARE) { + down_write(&shrinker_rwsem); + unregister_memcg_shrinker(shrinker); + up_write(&shrinker_rwsem); + } + + kfree(shrinker->nr_deferred); + shrinker->nr_deferred = NULL; + + kfree(shrinker); +} +EXPORT_SYMBOL(shrinker_free_non_registered); + +void shrinker_register(struct shrinker *shrinker) +{ + down_write(&shrinker_rwsem); + list_add_tail(&shrinker->list, &shrinker_list); + shrinker->flags |= SHRINKER_REGISTERED; + shrinker_debugfs_add(shrinker); + up_write(&shrinker_rwsem); +} +EXPORT_SYMBOL(shrinker_register); + +void shrinker_unregister(struct shrinker *shrinker) +{ + struct dentry *debugfs_entry; + int debugfs_id; + + if (!shrinker || !(shrinker->flags & SHRINKER_REGISTERED)) + return; + + down_write(&shrinker_rwsem); + list_del(&shrinker->list); + shrinker->flags &= ~SHRINKER_REGISTERED; + if (shrinker->flags & SHRINKER_MEMCG_AWARE) + unregister_memcg_shrinker(shrinker); + debugfs_entry = shrinker_debugfs_detach(shrinker, &debugfs_id); + up_write(&shrinker_rwsem); + + shrinker_debugfs_remove(debugfs_entry, debugfs_id); + + kfree(shrinker->nr_deferred); + shrinker->nr_deferred = NULL; + + kfree(shrinker); +} +EXPORT_SYMBOL(shrinker_unregister); + /* * Add a shrinker callback to be called from the vm. */