From patchwork Wed Sep 8 02:57:01 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrew Morton X-Patchwork-Id: 12479931 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id DB9EAC433EF for ; Wed, 8 Sep 2021 02:57:04 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 8B3556113C for ; Wed, 8 Sep 2021 02:57:04 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 8B3556113C Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvack.org Received: by kanga.kvack.org (Postfix) id 2DCC294001D; Tue, 7 Sep 2021 22:57:04 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 28D97900003; Tue, 7 Sep 2021 22:57:04 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 17AFC94001D; Tue, 7 Sep 2021 22:57:04 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0120.hostedemail.com [216.40.44.120]) by kanga.kvack.org (Postfix) with ESMTP id 045B4900003 for ; Tue, 7 Sep 2021 22:57:04 -0400 (EDT) Received: from smtpin01.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id B742D181CC1C8 for ; Wed, 8 Sep 2021 02:57:03 +0000 (UTC) X-FDA: 78562894326.01.D5B4281 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf26.hostedemail.com (Postfix) with ESMTP id 579F520019D3 for ; Wed, 8 Sep 2021 02:57:03 +0000 (UTC) Received: by mail.kernel.org (Postfix) with ESMTPSA id 9693661100; Wed, 8 Sep 2021 02:57:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1631069822; bh=kAH/4Gque9Iu3RmFULzQzVdjIQLZoEM28mV7h2vs7aE=; h=Date:From:To:Subject:In-Reply-To:From; b=s0Waqk9TmQWuqg+ZlE7Xo0NhArDkHFDhMa1x0j98lZnEl/J4+JYHUucYvp+chrNL7 sh8EJQ1EWKw0IvtZQd/Asv+uvQVFlT3HLJnA41YSMp9BfOL/Wp5+Ut8AU4u0yuZaNj tEbZr6twUvBmxGsO69jjdaLH6lL+SKk9PReIHJaM= Date: Tue, 07 Sep 2021 19:57:01 -0700 From: Andrew Morton To: akpm@linux-foundation.org, alexander.shishkin@linux.intel.com, amit@kernel.org, benh@kernel.crashing.org, brendanhiggins@google.com, corbet@lwn.net, david@redhat.com, dwmw@amazon.com, elver@google.com, fan.du@intel.com, foersleo@amazon.de, greg@kroah.com, gthelen@google.com, joe@perches.com, Jonathan.Cameron@huawei.com, linux-mm@kvack.org, markubo@amazon.de, mgorman@suse.de, mheyne@amazon.de, minchan@kernel.org, mingo@redhat.com, mm-commits@vger.kernel.org, namhyung@kernel.org, peterz@infradead.org, riel@surriel.com, rientjes@google.com, rostedt@goodmis.org, shakeelb@google.com, shuah@kernel.org, sieberf@amazon.com, sjpark@amazon.de, torvalds@linux-foundation.org, vbabka@suse.cz, vdavydov.dev@gmail.com Subject: [patch 071/147] mm/damon/dbgfs: support multiple contexts Message-ID: <20210908025701.uC8WKbLxx%akpm@linux-foundation.org> In-Reply-To: <20210907195226.14b1d22a07c085b22968b933@linux-foundation.org> User-Agent: s-nail v14.8.16 Authentication-Results: imf26.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=korg header.b=s0Waqk9T; spf=pass (imf26.hostedemail.com: domain of akpm@linux-foundation.org designates 198.145.29.99 as permitted sender) smtp.mailfrom=akpm@linux-foundation.org; dmarc=none X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 579F520019D3 X-Stat-Signature: 46qt9o7zq33uznuqw7zecucyq5fijoff X-HE-Tag: 1631069823-763348 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: From: SeongJae Park Subject: mm/damon/dbgfs: support multiple contexts In some use cases, users would want to run multiple monitoring context. For example, if a user wants a high precision monitoring and dedicating multiple CPUs for the job is ok, because DAMON creates one monitoring thread per one context, the user can split the monitoring target regions into multiple small regions and create one context for each region. Or, someone might want to simultaneously monitor different address spaces, e.g., both virtual address space and physical address space. The DAMON's API allows such usage, but 'damon-dbgfs' does not. Therefore, only kernel space DAMON users can do multiple contexts monitoring. This commit allows the user space DAMON users to use multiple contexts monitoring by introducing two new 'damon-dbgfs' debugfs files, 'mk_context' and 'rm_context'. Users can create a new monitoring context by writing the desired name of the new context to 'mk_context'. Then, a new directory with the name and having the files for setting of the context ('attrs', 'target_ids' and 'record') will be created under the debugfs directory. Writing the name of the context to remove to 'rm_context' will remove the related context and directory. Link: https://lkml.kernel.org/r/20210716081449.22187-10-sj38.park@gmail.com Signed-off-by: SeongJae Park Reviewed-by: Fernand Sieber Cc: Alexander Shishkin Cc: Amit Shah Cc: Benjamin Herrenschmidt Cc: Brendan Higgins Cc: David Hildenbrand Cc: David Rientjes Cc: David Woodhouse Cc: Fan Du Cc: Greg Kroah-Hartman Cc: Greg Thelen Cc: Ingo Molnar Cc: Joe Perches Cc: Jonathan Cameron Cc: Jonathan Corbet Cc: Leonard Foerster Cc: Marco Elver Cc: Markus Boehme Cc: Maximilian Heyne Cc: Mel Gorman Cc: Minchan Kim Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Rik van Riel Cc: Shakeel Butt Cc: Shuah Khan Cc: Steven Rostedt (VMware) Cc: Vladimir Davydov Cc: Vlastimil Babka Signed-off-by: Andrew Morton --- mm/damon/dbgfs.c | 195 ++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 193 insertions(+), 2 deletions(-) --- a/mm/damon/dbgfs.c~mm-damon-dbgfs-support-multiple-contexts +++ a/mm/damon/dbgfs.c @@ -18,6 +18,7 @@ static struct damon_ctx **dbgfs_ctxs; static int dbgfs_nr_ctxs; static struct dentry **dbgfs_dirs; +static DEFINE_MUTEX(damon_dbgfs_lock); /* * Returns non-empty string on success, negative error code otherwise. @@ -328,6 +329,186 @@ static struct damon_ctx *dbgfs_new_ctx(v return ctx; } +static void dbgfs_destroy_ctx(struct damon_ctx *ctx) +{ + damon_destroy_ctx(ctx); +} + +/* + * Make a context of @name and create a debugfs directory for it. + * + * This function should be called while holding damon_dbgfs_lock. + * + * Returns 0 on success, negative error code otherwise. + */ +static int dbgfs_mk_context(char *name) +{ + struct dentry *root, **new_dirs, *new_dir; + struct damon_ctx **new_ctxs, *new_ctx; + + if (damon_nr_running_ctxs()) + return -EBUSY; + + new_ctxs = krealloc(dbgfs_ctxs, sizeof(*dbgfs_ctxs) * + (dbgfs_nr_ctxs + 1), GFP_KERNEL); + if (!new_ctxs) + return -ENOMEM; + dbgfs_ctxs = new_ctxs; + + new_dirs = krealloc(dbgfs_dirs, sizeof(*dbgfs_dirs) * + (dbgfs_nr_ctxs + 1), GFP_KERNEL); + if (!new_dirs) + return -ENOMEM; + dbgfs_dirs = new_dirs; + + root = dbgfs_dirs[0]; + if (!root) + return -ENOENT; + + new_dir = debugfs_create_dir(name, root); + dbgfs_dirs[dbgfs_nr_ctxs] = new_dir; + + new_ctx = dbgfs_new_ctx(); + if (!new_ctx) { + debugfs_remove(new_dir); + dbgfs_dirs[dbgfs_nr_ctxs] = NULL; + return -ENOMEM; + } + + dbgfs_ctxs[dbgfs_nr_ctxs] = new_ctx; + dbgfs_fill_ctx_dir(dbgfs_dirs[dbgfs_nr_ctxs], + dbgfs_ctxs[dbgfs_nr_ctxs]); + dbgfs_nr_ctxs++; + + return 0; +} + +static ssize_t dbgfs_mk_context_write(struct file *file, + const char __user *buf, size_t count, loff_t *ppos) +{ + char *kbuf; + char *ctx_name; + ssize_t ret = count; + int err; + + kbuf = user_input_str(buf, count, ppos); + if (IS_ERR(kbuf)) + return PTR_ERR(kbuf); + ctx_name = kmalloc(count + 1, GFP_KERNEL); + if (!ctx_name) { + kfree(kbuf); + return -ENOMEM; + } + + /* Trim white space */ + if (sscanf(kbuf, "%s", ctx_name) != 1) { + ret = -EINVAL; + goto out; + } + + mutex_lock(&damon_dbgfs_lock); + err = dbgfs_mk_context(ctx_name); + if (err) + ret = err; + mutex_unlock(&damon_dbgfs_lock); + +out: + kfree(kbuf); + kfree(ctx_name); + return ret; +} + +/* + * Remove a context of @name and its debugfs directory. + * + * This function should be called while holding damon_dbgfs_lock. + * + * Return 0 on success, negative error code otherwise. + */ +static int dbgfs_rm_context(char *name) +{ + struct dentry *root, *dir, **new_dirs; + struct damon_ctx **new_ctxs; + int i, j; + + if (damon_nr_running_ctxs()) + return -EBUSY; + + root = dbgfs_dirs[0]; + if (!root) + return -ENOENT; + + dir = debugfs_lookup(name, root); + if (!dir) + return -ENOENT; + + new_dirs = kmalloc_array(dbgfs_nr_ctxs - 1, sizeof(*dbgfs_dirs), + GFP_KERNEL); + if (!new_dirs) + return -ENOMEM; + + new_ctxs = kmalloc_array(dbgfs_nr_ctxs - 1, sizeof(*dbgfs_ctxs), + GFP_KERNEL); + if (!new_ctxs) { + kfree(new_dirs); + return -ENOMEM; + } + + for (i = 0, j = 0; i < dbgfs_nr_ctxs; i++) { + if (dbgfs_dirs[i] == dir) { + debugfs_remove(dbgfs_dirs[i]); + dbgfs_destroy_ctx(dbgfs_ctxs[i]); + continue; + } + new_dirs[j] = dbgfs_dirs[i]; + new_ctxs[j++] = dbgfs_ctxs[i]; + } + + kfree(dbgfs_dirs); + kfree(dbgfs_ctxs); + + dbgfs_dirs = new_dirs; + dbgfs_ctxs = new_ctxs; + dbgfs_nr_ctxs--; + + return 0; +} + +static ssize_t dbgfs_rm_context_write(struct file *file, + const char __user *buf, size_t count, loff_t *ppos) +{ + char *kbuf; + ssize_t ret = count; + int err; + char *ctx_name; + + kbuf = user_input_str(buf, count, ppos); + if (IS_ERR(kbuf)) + return PTR_ERR(kbuf); + ctx_name = kmalloc(count + 1, GFP_KERNEL); + if (!ctx_name) { + kfree(kbuf); + return -ENOMEM; + } + + /* Trim white space */ + if (sscanf(kbuf, "%s", ctx_name) != 1) { + ret = -EINVAL; + goto out; + } + + mutex_lock(&damon_dbgfs_lock); + err = dbgfs_rm_context(ctx_name); + if (err) + ret = err; + mutex_unlock(&damon_dbgfs_lock); + +out: + kfree(kbuf); + kfree(ctx_name); + return ret; +} + static ssize_t dbgfs_monitor_on_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) { @@ -370,6 +551,14 @@ static ssize_t dbgfs_monitor_on_write(st return ret; } +static const struct file_operations mk_contexts_fops = { + .write = dbgfs_mk_context_write, +}; + +static const struct file_operations rm_contexts_fops = { + .write = dbgfs_rm_context_write, +}; + static const struct file_operations monitor_on_fops = { .read = dbgfs_monitor_on_read, .write = dbgfs_monitor_on_write, @@ -378,8 +567,10 @@ static const struct file_operations moni static int __init __damon_dbgfs_init(void) { struct dentry *dbgfs_root; - const char * const file_names[] = {"monitor_on"}; - const struct file_operations *fops[] = {&monitor_on_fops}; + const char * const file_names[] = {"mk_contexts", "rm_contexts", + "monitor_on"}; + const struct file_operations *fops[] = {&mk_contexts_fops, + &rm_contexts_fops, &monitor_on_fops}; int i; dbgfs_root = debugfs_create_dir("damon", NULL);