From mboxrd@z Thu Jan 1 00:00:00 1970 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=unavailable 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 69721C433E0 for ; Thu, 4 Feb 2021 15:39:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3CA8064F47 for ; Thu, 4 Feb 2021 15:39:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237500AbhBDPje (ORCPT ); Thu, 4 Feb 2021 10:39:34 -0500 Received: from smtp-fw-33001.amazon.com ([207.171.190.10]:59028 "EHLO smtp-fw-33001.amazon.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237381AbhBDPgA (ORCPT ); Thu, 4 Feb 2021 10:36:00 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1612452959; x=1643988959; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version; bh=GvQHGg8Fg9cuT3SeiFVEkCtDNQ9QA2fEAQ+quD3Tkys=; b=SIQ+wTw5Lw5kofb4e6qhXLnDA7IE3S/ERP3ldjbqdRQwHHxsIERxmelD bmN7G5HFdN6EOEmA9XJzNf93c3VsKeqnkEN3eFHZmbK9v7wpfFzbQviR6 sHkUWm5Au/csq5a1jjT+A+dNyvVUlz2xyrejum+i6IWoPlm5zPS7CiU1n w=; 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 Content-Type: text/plain 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) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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++) { -- 2.17.1