From patchwork Thu Feb 4 15:31:45 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: SeongJae Park X-Patchwork-Id: 12067601 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=-19.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT 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 CAECDC433DB for ; Thu, 4 Feb 2021 15:35:21 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 70CBD64E27 for ; Thu, 4 Feb 2021 15:35:21 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 70CBD64E27 Authentication-Results: mail.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=amazon.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 19B976B0078; Thu, 4 Feb 2021 10:35:21 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 14B1B6B007B; Thu, 4 Feb 2021 10:35:21 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 039866B007D; Thu, 4 Feb 2021 10:35:20 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0164.hostedemail.com [216.40.44.164]) by kanga.kvack.org (Postfix) with ESMTP id E26B26B0078 for ; Thu, 4 Feb 2021 10:35:20 -0500 (EST) Received: from smtpin27.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id A4E1E180AD820 for ; Thu, 4 Feb 2021 15:35:20 +0000 (UTC) X-FDA: 77780984400.27.anger09_080f7af275dd Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin27.hostedemail.com (Postfix) with ESMTP id 809583D663 for ; Thu, 4 Feb 2021 15:35:20 +0000 (UTC) X-HE-Tag: anger09_080f7af275dd X-Filterd-Recvd-Size: 5325 Received: from smtp-fw-33001.amazon.com (smtp-fw-33001.amazon.com [207.171.190.10]) by imf50.hostedemail.com (Postfix) with ESMTP for ; Thu, 4 Feb 2021 15:35:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1612452920; x=1643988920; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version; bh=GvQHGg8Fg9cuT3SeiFVEkCtDNQ9QA2fEAQ+quD3Tkys=; b=IjZVz76YfO+8JsqhjS+dJBfrQ2kHKjS7tnv+5NzYureuwYdzoy/Ab6fs rrYu2bEWSF0U1SNrSfNdc7IfftoXMoJi2j/yloMtyZ+iZHJspVhMMtjZk VJQAGRwT8RqZIFhutRhQypy4dJInzucJi5NOc9SoCyjif9m2NKmoWPpzQ c=; X-IronPort-AV: E=Sophos;i="5.79,401,1602547200"; d="scan'208";a="115853146" Received: from sea32-co-svc-lb4-vlan3.sea.corp.amazon.com (HELO email-inbound-relay-1a-af6a10df.us-east-1.amazon.com) ([10.47.23.38]) by smtp-border-fw-out-33001.sea14.amazon.com with ESMTP; 04 Feb 2021 15:35:16 +0000 Received: from EX13D31EUA001.ant.amazon.com (iad12-ws-svc-p26-lb9-vlan3.iad.amazon.com [10.40.163.38]) by email-inbound-relay-1a-af6a10df.us-east-1.amazon.com (Postfix) with ESMTPS id 03125A1E24; Thu, 4 Feb 2021 15:35:03 +0000 (UTC) Received: from u3f2cd687b01c55.ant.amazon.com (10.43.161.146) by EX13D31EUA001.ant.amazon.com (10.43.165.15) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Thu, 4 Feb 2021 15:34:47 +0000 From: SeongJae Park To: CC: SeongJae Park , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , Subject: [PATCH v24 09/14] mm/damon/dbgfs: Export kdamond pid to the user space Date: Thu, 4 Feb 2021 16:31:45 +0100 Message-ID: <20210204153150.15948-10-sjpark@amazon.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20210204153150.15948-1-sjpark@amazon.com> References: <20210204153150.15948-1-sjpark@amazon.com> MIME-Version: 1.0 X-Originating-IP: [10.43.161.146] X-ClientProxiedBy: EX13D18UWA001.ant.amazon.com (10.43.160.11) To EX13D31EUA001.ant.amazon.com (10.43.165.15) 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 For CPU usage accounting, knowing pid of the monitoring thread could be helpful. For example, users could use cpuaccount cgroups with the pid. This commit therefore exports the pid of currently running monitoring thread to the user space via 'kdamond_pid' file in the debugfs directory. Signed-off-by: SeongJae Park --- mm/damon/dbgfs.c | 37 +++++++++++++++++++++++++++++++++++-- 1 file changed, 35 insertions(+), 2 deletions(-) diff --git a/mm/damon/dbgfs.c b/mm/damon/dbgfs.c index dce4409e5887..4b9ac2043e99 100644 --- a/mm/damon/dbgfs.c +++ b/mm/damon/dbgfs.c @@ -358,6 +358,32 @@ static ssize_t dbgfs_target_ids_write(struct file *file, return ret; } +static ssize_t dbgfs_kdamond_pid_read(struct file *file, + char __user *buf, size_t count, loff_t *ppos) +{ + struct damon_ctx *ctx = file->private_data; + char *kbuf; + ssize_t len; + + kbuf = kmalloc(count, GFP_KERNEL); + if (!kbuf) + return -ENOMEM; + + mutex_lock(&ctx->kdamond_lock); + if (ctx->kdamond) + len = scnprintf(kbuf, count, "%d\n", ctx->kdamond->pid); + else + len = scnprintf(kbuf, count, "none\n"); + mutex_unlock(&ctx->kdamond_lock); + if (!len) + goto out; + len = simple_read_from_buffer(buf, count, ppos, kbuf, len); + +out: + kfree(kbuf); + return len; +} + static int damon_dbgfs_open(struct inode *inode, struct file *file) { file->private_data = inode->i_private; @@ -386,11 +412,18 @@ static const struct file_operations target_ids_fops = { .write = dbgfs_target_ids_write, }; +static const struct file_operations kdamond_pid_fops = { + .owner = THIS_MODULE, + .open = damon_dbgfs_open, + .read = dbgfs_kdamond_pid_read, +}; + static int dbgfs_fill_ctx_dir(struct dentry *dir, struct damon_ctx *ctx) { - const char * const file_names[] = {"attrs", "record", "target_ids"}; + const char * const file_names[] = {"attrs", "record", "target_ids", + "kdamond_pid"}; const struct file_operations *fops[] = {&attrs_fops, &record_fops, - &target_ids_fops}; + &target_ids_fops, &kdamond_pid_fops}; int i; for (i = 0; i < ARRAY_SIZE(file_names); i++) {