From patchwork Mon Mar 17 19:40:04 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Joel Granados X-Patchwork-Id: 14019915 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2A25EF9DA; Mon, 17 Mar 2025 19:41:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742240464; cv=none; b=abnf/nFcVp0CIXXwU+av5c/7Pu4CoTykjG/N2k7D4ssd3y/N5MdKYim9mxtmi4RbFtGZZ1BlAVmoIVIpV7L6y3LgQ1kt4OgGIwqjWenndvwlbjh1EP9BnENDcyVay/QMb2QErwoTurczzh7oChrizSj+L4M4lL2iikt2B5afXzA= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742240464; c=relaxed/simple; bh=nepMoQbELtF94lH7T+rYxLvz2Qh9WuaIy9QO1v1CDrQ=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:To:Cc; b=Raas2ymqG7jnY0VdyYhpFvmR+wfZhM80zQ7IhbWW9BOSY+6hSTyHYwUKF98bkUQo0ySflMh+Ji8Axo7NAon0pxFgFLX8nKBRuWHXfPBDOHUSGminTh5M3c+BQ/NeJZ82WGXWkksARr1Vc0Qwe2It3I5/XYoBaEZaftne86AU+3g= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=mbTltoax; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="mbTltoax" Received: by smtp.kernel.org (Postfix) with ESMTPS id 9354BC4CEE3; Mon, 17 Mar 2025 19:41:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1742240463; bh=nepMoQbELtF94lH7T+rYxLvz2Qh9WuaIy9QO1v1CDrQ=; h=From:Date:Subject:To:Cc:From; b=mbTltoaxCF/20PAdD+F5yABlHph1lzXaz3O8SIAtJDVpLYCJUUwplaXwvnAira745 Z0jhDlvde0qpxsKqfK4ST5Jo/WJyATcgnpLiry31xd4MfqP1tva71KB3hG+Qnc8GKc kyuBIZAXGOHwm/7cVO8dvx1ZY0AEETopY8TtXOypPphrgz7/9AFdmnxfySATBEGUkN ZETP10ZSfHEEboaPHrzSu/O9/ndzQzb5ITCHx1Kzs66ghOS3pStZuqRyM/JX8fNZWd Xcrr+UONCJhBPvzO0ZrByEqgBQ4lsqOko8vNUBbPh8QacFsxbMSaDCkdj+R3OVdghG raY1k7srXseGg== Received: from aws-us-west-2-korg-lkml-1.web.codeaurora.org (localhost.localdomain [127.0.0.1]) by smtp.lore.kernel.org (Postfix) with ESMTP id 877E4C282EC; Mon, 17 Mar 2025 19:41:03 +0000 (UTC) From: Joel Granados Date: Mon, 17 Mar 2025 20:40:04 +0100 Subject: [PATCH v2] drop_caches: Allow re-enabling message after disabling Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-Id: <20250317-jag-drop_caches_msg-v2-1-e22d9a6a3038@kernel.org> X-B4-Tracking: v=1; b=H4sIAJN62GcC/32NWQrCMBRFt1Let5FmKBW/3IeUkqQvg0NSXqQop Xs3dgF+ngP33BUKUsQC52YFwiWWmFMFcWjABp08sjhVBtGKrpVcspv2bKI8j1bbgGV8Fs+scsb hZDruJNTlTOjie69eh8ohllemz36y8J/931s448wKVNifemV6cbkjJXwcM3kYtm37Aq8QtE63A AAA X-Change-ID: 20250313-jag-drop_caches_msg-c4fbfedb51f3 To: Jonathan Corbet , Alexander Viro , Christian Brauner , Jan Kara Cc: linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, Ruiwu Chen , Luis Chamberlain , Joel Granados X-Mailer: b4 0.14.2 X-Developer-Signature: v=1; a=openpgp-sha256; l=2047; i=joel.granados@kernel.org; h=from:subject:message-id; bh=nepMoQbELtF94lH7T+rYxLvz2Qh9WuaIy9QO1v1CDrQ=; b=owJ4nAHtARL+kA0DAAoBupfNUreWQU8ByyZiAGfYerHFV+3h8K+5MCKKabYyQ8sg92A8cm7yh koRx26w9cfa1okBswQAAQoAHRYhBK5HCVcl5jElzssnkLqXzVK3lkFPBQJn2HqxAAoJELqXzVK3 lkFPntoL/RNNBaAKCSj2xAgD7QJjEvjW4CWP0y8gRIjAJ4yTFX5L7PrDAsvjalhDJSUgvZYv+lh KusABjpK8ywfgLCrYxEPqgh8WaPxaeAJSHIfcb0MIKMIxFHrtsjP9EdSn3uSqa/11M9ESSBu1Km uTU2wLN4MO1fLE4G6wfjvOHu7KDS9y1RKnDqnsX+Ox7sXjjKyQhxrUmWCbII5VI3MwQ8tI2OmRh +lgHPk/4SVf8JAi0uZc2dyLDAWE4chvfoFOOJ3MadcGNSlNRlPKVFX6PIjtndgIo5OAz4tRqTbS lF8dWG15fFl/n3HuHvnSszCSRxhU5FEcTGhZHVrzNFUk/KjsUYGIXlg5y5yFGSrYZFn6dpHr/ef JnM07cKKHzlJ8pONnmEfv5x8xLCfr3r25QMZNS5gsD57rK9jDobm8IwSa7+UZKOD39hGVLEXmix Qq8Aiifpp+tfY80UETeY3BUzBT2I7jdW3XxA1+kEiY9186qg5/gFomLYq9OFtvKvihwFq4GdoB7 Pw= X-Developer-Key: i=joel.granados@kernel.org; a=openpgp; fpr=F1F8E46D30F0F6C4A45FF4465895FAAC338C6E77 X-Endpoint-Received: by B4 Relay for joel.granados@kernel.org/default with auth_id=239 After writing "4" to /proc/sys/vm/drop_caches there was no way to re-enable the drop_caches kernel message. By replacing the "or" assignment for the stfu variable, it is now possible to toggle the message on and off by setting the 4th bit in /proc/sys/vm/drop_caches. Signed-off-by: Joel Granados --- Changes in v2: - Check the 4 bit before we actualy toggle the message - Link to v1: https://lore.kernel.org/r/20250313-jag-drop_caches_msg-v1-1-c2e4e7874b72@kernel.org --- --- Documentation/admin-guide/sysctl/vm.rst | 2 +- fs/drop_caches.c | 3 ++- 2 files changed, 3 insertions(+), 2 deletions(-) --- base-commit: 7eb172143d5508b4da468ed59ee857c6e5e01da6 change-id: 20250313-jag-drop_caches_msg-c4fbfedb51f3 Best regards, diff --git a/Documentation/admin-guide/sysctl/vm.rst b/Documentation/admin-guide/sysctl/vm.rst index f48eaa98d22d2b575f6e913f437b0d548daac3e6..75a032f8cbfb4e05f04610cca219d154bd852789 100644 --- a/Documentation/admin-guide/sysctl/vm.rst +++ b/Documentation/admin-guide/sysctl/vm.rst @@ -266,7 +266,7 @@ used:: cat (1234): drop_caches: 3 These are informational only. They do not mean that anything is wrong -with your system. To disable them, echo 4 (bit 2) into drop_caches. +with your system. To toggle them, echo 4 (bit 2) into drop_caches. enable_soft_offline =================== diff --git a/fs/drop_caches.c b/fs/drop_caches.c index d45ef541d848a73cbd19205e0111c2cab3b73617..15730593ae39955ae7ae93aec17546fc96f89dce 100644 --- a/fs/drop_caches.c +++ b/fs/drop_caches.c @@ -68,12 +68,13 @@ int drop_caches_sysctl_handler(const struct ctl_table *table, int write, drop_slab(); count_vm_event(DROP_SLAB); } + if (sysctl_drop_caches & 4) + stfu ^= 1; if (!stfu) { pr_info("%s (%d): drop_caches: %d\n", current->comm, task_pid_nr(current), sysctl_drop_caches); } - stfu |= sysctl_drop_caches & 4; } return 0; }