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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 45994C433EF for ; Wed, 20 Oct 2021 01:42:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2C77661167 for ; Wed, 20 Oct 2021 01:42:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229878AbhJTBoy (ORCPT ); Tue, 19 Oct 2021 21:44:54 -0400 Received: from out30-44.freemail.mail.aliyun.com ([115.124.30.44]:42113 "EHLO out30-44.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229750AbhJTBov (ORCPT ); Tue, 19 Oct 2021 21:44:51 -0400 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R131e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e04400;MF=xhao@linux.alibaba.com;NM=1;PH=DS;RN=5;SR=0;TI=SMTPD_---0Ut.2tuf_1634694154; Received: from localhost.localdomain(mailfrom:xhao@linux.alibaba.com fp:SMTPD_---0Ut.2tuf_1634694154) by smtp.aliyun-inc.com(127.0.0.1); Wed, 20 Oct 2021 09:42:36 +0800 From: Xin Hao To: sjpark@amazon.de Cc: xhao@linux.alibaba.com, akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [PATCH v3 2/2] mm/damon/dbgfs: Add adaptive_targets list check before enable monitor_on Date: Wed, 20 Oct 2021 09:42:33 +0800 Message-Id: X-Mailer: git-send-email 2.31.0 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When the ctx->adaptive_targets list is empty, I did some test on monitor_on interface like this. # echo > /sys/kernel/debug/damon/target_ids Though the ctx->adaptive_targets list is empty, but the kthread_run still be called, and the kdamond.x thread still be created, this is meaningless. So there adds a judgment in 'dbgfs_monitor_on_write', if the ctx->adaptive_targets list is empty, return -EINVAL. Signed-off-by: Xin Hao --- include/linux/damon.h | 1 + mm/damon/core.c | 5 +++++ mm/damon/dbgfs.c | 13 ++++++++++--- 3 files changed, 16 insertions(+), 3 deletions(-) diff --git a/include/linux/damon.h b/include/linux/damon.h index 715dadd21f7c..4fce5f1f6dad 100644 --- a/include/linux/damon.h +++ b/include/linux/damon.h @@ -316,6 +316,7 @@ void damon_destroy_scheme(struct damos *s); struct damon_target *damon_new_target(unsigned long id); void damon_add_target(struct damon_ctx *ctx, struct damon_target *t); +bool damon_targets_empty(struct damon_ctx *ctx); void damon_free_target(struct damon_target *t); void damon_destroy_target(struct damon_target *t); unsigned int damon_nr_regions(struct damon_target *t); diff --git a/mm/damon/core.c b/mm/damon/core.c index 2f6785737902..c3a1374dbe0b 100644 --- a/mm/damon/core.c +++ b/mm/damon/core.c @@ -156,6 +156,11 @@ void damon_add_target(struct damon_ctx *ctx, struct damon_target *t) list_add_tail(&t->list, &ctx->adaptive_targets); } +bool damon_targets_empty(struct damon_ctx *ctx) +{ + return list_empty(&ctx->adaptive_targets); +} + static void damon_del_target(struct damon_target *t) { list_del(&t->list); diff --git a/mm/damon/dbgfs.c b/mm/damon/dbgfs.c index 38188347d8ab..9dee29f7d103 100644 --- a/mm/damon/dbgfs.c +++ b/mm/damon/dbgfs.c @@ -865,12 +865,19 @@ static ssize_t dbgfs_monitor_on_write(struct file *file, return -EINVAL; } - if (!strncmp(kbuf, "on", count)) + if (!strncmp(kbuf, "on", count)) { + int i; + + for (i = 0; i < dbgfs_nr_ctxs; i++) { + if (damon_targets_empty(dbgfs_ctxs[i])) + return -EINVAL; + } err = damon_start(dbgfs_ctxs, dbgfs_nr_ctxs); - else if (!strncmp(kbuf, "off", count)) + } else if (!strncmp(kbuf, "off", count)) { err = damon_stop(dbgfs_ctxs, dbgfs_nr_ctxs); - else + } else { err = -EINVAL; + } if (err) ret = err; -- 2.31.0