From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.12]) (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 C43253AB275 for ; Tue, 7 Apr 2026 16:02:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.12 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775577747; cv=none; b=lKOsOMpprwiVrNFCyCu0Q7MpFu+KiZcrptkDjPmh1pLbLi1SKsc7R22G3g3DJXIbqpYg0ua2J98hgSd8+01GYpEF8wRO7pX4ZxU/j5Y3MDyIbMvNqD1yQyDcqOGw/GOiQPdo59x/Kjpqw2EU2nfhzqY0/uypoBTQOrFyv38cL18= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775577747; c=relaxed/simple; bh=EkhkDmw+ds9/eOTSV+LXXneT2S29y5By4Zed2fnWFrg=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version:Content-Type; b=VrwJaH52l0C5+LTU0GG2zi8aJp3+i2K0d+egC1y1BZVfnFnVqROFIsqJ2084EeWUzIIbYso27qjT2nOXxggDZ1MnpvzmCdid2bMLDDR1NkNPcA4urRd5GywbXX+pBMeP1nGL0xzNbPGdiuwYbDGjhUym/GNC2uV8dYEm1Gl2CYs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com; spf=pass smtp.mailfrom=intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=b3W6Q4kq; arc=none smtp.client-ip=192.198.163.12 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="b3W6Q4kq" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1775577741; x=1807113741; h=from:to:cc:subject:date:message-id:mime-version: content-transfer-encoding; bh=EkhkDmw+ds9/eOTSV+LXXneT2S29y5By4Zed2fnWFrg=; b=b3W6Q4kqPf8AYSfR9LXyhXPXyEs4nBM8jRKAb90D6r6N47OBHzxQeL3n saw8QvUhg72YW6L7Yx4BOkK6h0nULbG00FjgUg5bxxZNS7PHjStApvTzs xNeFw3vBcLgrJgGPq5qQMbW6VFGCgu0kdEKjRpmn9ATxg4CxlNBPsWkMj AOjjy1ljlQV7zC6wkToxvWV9xpg7P83PhqyMrTzSrqjRdRBvqGHOXKUdS S2QGMLEQ/WdzyfiR1L0AVmFmDspXEsNX467RL++7fdk9jmMgNChRmXSjF /R7EZgZhNN3QuT6vaMCfqephrR9ajj8id3MqUVUChFcz8IB99Bxmpp0T5 A==; X-CSE-ConnectionGUID: /Wy7GTF4SrmjLBx2TrAyXw== X-CSE-MsgGUID: d6ea9/qmTL6bV9a8B0ia1w== X-IronPort-AV: E=McAfee;i="6800,10657,11752"; a="80432633" X-IronPort-AV: E=Sophos;i="6.23,165,1770624000"; d="scan'208";a="80432633" Received: from orviesa009.jf.intel.com ([10.64.159.149]) by fmvoesa106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 07 Apr 2026 09:02:18 -0700 X-CSE-ConnectionGUID: yP78gzZnRM2J4hpKjfXIOA== X-CSE-MsgGUID: zrRE+pCfTGOmvzlhKDDgLA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.23,165,1770624000"; d="scan'208";a="228119027" Received: from rchatre-desk1.jf.intel.com ([10.165.154.99]) by orviesa009-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 07 Apr 2026 09:02:18 -0700 From: Reinette Chatre To: tony.luck@intel.com, james.morse@arm.com, Dave.Martin@arm.com, babu.moger@amd.com, bp@alien8.de, tglx@linutronix.de, dave.hansen@linux.intel.com Cc: x86@kernel.org, hpa@zytor.com, ben.horgan@arm.com, fustini@kernel.org, fenghuay@nvidia.com, peternewman@google.com, linux-kernel@vger.kernel.org, patches@lists.linux.dev, reinette.chatre@intel.com Subject: [PATCH v3 00/13] x86,fs/resctrl: Improve resctrl quality and consistency Date: Tue, 7 Apr 2026 09:01:57 -0700 Message-ID: X-Mailer: git-send-email 2.50.1 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Changes since v2: - v2: https://lore.kernel.org/lkml/cover.1774043709.git.reinette.chatre@intel.com/ - Rebased on top of tip/master with pending resctrl selftest changes, https://lore.kernel.org/lkml/cover.1775266384.git.reinette.chatre@intel.com/, applied on top to support testing with latest kernel that has pending resctrl changes merged. - Drop "fs/resctrl: Use stricter checks on input to cpus/cpus_list file" that ended up being too strict and removed one use case. (Chris) - max_threshold_occ_write() switch to guard(). (Chenyu) - Add more detail to one return value description. - Add tags. - No opinions so far on needing to update last_cmd_status on success of all read commands. At this time last_cmd_status will continue to return previous failure message (if any) after a read command accessing static data succeeds. Changes since v1: - v1: https://lore.kernel.org/lkml/cover.1772476561.git.reinette.chatre@intel.com/ - To simplify tracking, include patch to MAINTAINERS submitted separately: https://lore.kernel.org/lkml/4274c478922c01f9ceebc805acf991f10a95519f.1771442788.git.reinette.chatre@intel.com/ - Follow recent upstream changes to add reference to tip tree handbook in MAINTAINERS entry. - Use new pattern in resctrl to enable looping over all entries of an enum while making adding new enum entries more clear all while avoiding warnings when compiling with -Wswitch. (Ben) - Add another last_cmd_status enhancement that appends "[truncated]" to output of info/last_cmd_status if the backing buffer overflowed. - Please see patch changelogs for details of changes. - Add tags. Hi Everybody, This is a collection of resctrl cleanups assembled together for convenience and simpler tracking. I'd be happy to split them up if it makes review and/or handling easier. Summary of changes: - Let resctrl pass stricter checks from various tools to provide a cleaner baseline with the goal to promote healthier contributions: - ./tools/docs/kernel-doc -Wall -v - Build with W=12 - ./scripts/coccicheck - Static checkers - Use accurate and consistent type for all uses of resource ID. - In the unlikely scenario that resctrl picked a wrong CPU to read an event from, pass the error through to user space instead of claiming to succeed and returning a (wrong) result. - Since inception of last_cmd_status feature there have been mismatches between resctrl file operation failures and the contents of info/last_cmd_status. This pattern keeps propagating with each new resctrl feature. Establish a new baseline with a new pattern that ensures info/last_cmd_status contains an accurate failure description that matches the most recent resctrl file operation failure. One potential open: There remains an inconsistency between resctrl file operations that do/can _not_ fail and the contents of info/last_cmd_status. If a resctrl file operation fails and an informational error is printed to last_cmd_status then a subsequent reading of a resctrl file (specifically most of the files found in info/) may succeed while info/last_cmd_status may or may not return the error from previous failure. Ensuring last_cmd_status is reset on every read carries the cost of taking rdtgroup_mutex on several more user space initiated paths and thus increase contention on rdtgroup_mutex. I opted to not make this change and instead focus this work on ensuring that last_cmd_status is accurate whenever there is a failure during any resctrl file operation. Please let me know if you have opinions in this regard. Any feedback is appreciated. Regards, Reinette Reinette Chatre (13): MAINTAINERS: Update resctrl entry fs/resctrl: Add missing return value descriptions fs/resctrl: Avoid "may be used uninitialized" warning fs/resctrl: Use correct format specifier for printing error pointers x86/resctrl: Protect against bad shift fs/resctrl: Change pattern used to track number of entries in enum fs/resctrl: Use accurate type for rdt_resource::rid fs/resctrl: Pass error reading event through to user space fs/resctrl: Add last_cmd_status support for writes to max_threshold_occupancy fs/resctrl: Use accurate and symmetric exit flows fs/resctrl: Change last_cmd_status custom during input parsing fs/resctrl: Communicate resource group deleted error via last_cmd_status fs/resctrl: Inform user space when status buffer overflowed MAINTAINERS | 2 + arch/x86/kernel/cpu/resctrl/core.c | 4 +- fs/resctrl/ctrlmondata.c | 70 +++++++++------- fs/resctrl/monitor.c | 80 ++++++++++-------- fs/resctrl/pseudo_lock.c | 2 +- fs/resctrl/rdtgroup.c | 126 ++++++++++++++++++----------- include/linux/resctrl.h | 11 +-- 7 files changed, 180 insertions(+), 115 deletions(-) -- 2.50.1