From patchwork Tue Oct 19 14:26:04 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: haoxin X-Patchwork-Id: 12570059 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 A24F5C433F5 for ; Tue, 19 Oct 2021 14:26:14 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 4ED7061029 for ; Tue, 19 Oct 2021 14:26:14 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 4ED7061029 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.alibaba.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvack.org Received: by kanga.kvack.org (Postfix) id 675BA6B006C; Tue, 19 Oct 2021 10:26:13 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 62681900003; Tue, 19 Oct 2021 10:26:13 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 53BBB6B0072; Tue, 19 Oct 2021 10:26:13 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0236.hostedemail.com [216.40.44.236]) by kanga.kvack.org (Postfix) with ESMTP id 4669D6B006C for ; Tue, 19 Oct 2021 10:26:13 -0400 (EDT) Received: from smtpin33.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id 0606D181286E7 for ; Tue, 19 Oct 2021 14:26:13 +0000 (UTC) X-FDA: 78713411826.33.C4D285D Received: from out30-43.freemail.mail.aliyun.com (out30-43.freemail.mail.aliyun.com [115.124.30.43]) by imf01.hostedemail.com (Postfix) with ESMTP id C13BC5082987 for ; Tue, 19 Oct 2021 14:26:07 +0000 (UTC) X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R171e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e04407;MF=xhao@linux.alibaba.com;NM=1;PH=DS;RN=5;SR=0;TI=SMTPD_---0Usyv4Hp_1634653565; Received: from localhost.localdomain(mailfrom:xhao@linux.alibaba.com fp:SMTPD_---0Usyv4Hp_1634653565) by smtp.aliyun-inc.com(127.0.0.1); Tue, 19 Oct 2021 22:26:07 +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 v2 2/2] mm/damon/dbgfs: Add adaptive_targets list check before enable monitor_on Date: Tue, 19 Oct 2021 22:26:04 +0800 Message-Id: X-Mailer: git-send-email 2.31.0 In-Reply-To: References: MIME-Version: 1.0 X-Stat-Signature: 4mgqwmu66t9pb96yh46ux8ub3jyuep73 Authentication-Results: imf01.hostedemail.com; dkim=none; spf=pass (imf01.hostedemail.com: domain of xhao@linux.alibaba.com designates 115.124.30.43 as permitted sender) smtp.mailfrom=xhao@linux.alibaba.com; dmarc=pass (policy=none) header.from=alibaba.com X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: C13BC5082987 X-HE-Tag: 1634653567-450918 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: When the ctx->adaptive_targets list is empty, i did some test on monitor_on interface like this. echo on > /sys/kernel/debug/damon/monitor_on [ 851.988307] damon: kdamond (5390) starts 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 | 10 ++++++++-- 3 files changed, 14 insertions(+), 2 deletions(-) -- 2.31.0 diff --git a/include/linux/damon.h b/include/linux/damon.h index 715dadd21f7c..06acf73fe9db 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); +int damon_target_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..c651b49249e5 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); } +int damon_target_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..bac42dd358d1 100644 --- a/mm/damon/dbgfs.c +++ b/mm/damon/dbgfs.c @@ -865,9 +865,15 @@ 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_target_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 err = -EINVAL;