From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=198.175.65.16 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1792443060; b=JU3rKsbIqDdZcRJArrkDReHd+v4V87keiylUPY3j6W8vDIXaJ+9tJNzEpiz3+MeEqr58 XKqB1amLmX3EEGCceo6SkX9jCzr3dfaaCb3IqilhbkoVBtDEfCf9owcfh3ak3kmuTG8Y+ 6EfW93besd6u4D6jRII+wL9Ielzz7ZuQJOJwTayugITgc3BAAXN2Jb5hs7B/WZlvihyyk GrKekbaqk3WvIGnBxylOb7fgCv8neH6A9VgGC4RstLpS6wWqz/x4HstAFtF2zkVYKXqBv F8EtsIzzFI+89pIEPNxXA/u13TZkV5Vx3yasNYphD8n/YSRpfl+ZYPOhgupZSEk74uw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792443060; h=DMARC-Filter:DKIM-Signature:X-CSE-ConnectionGUID:X-CSE-MsgGUID: X-IronPort-AV:X-IronPort-AV:Received:X-CSE-ConnectionGUID: X-CSE-MsgGUID:X-ExtLoop1:X-IronPort-AV:Received:From:To:Cc:Subject: Date:Message-ID:X-Mailer:In-Reply-To:References:MIME-Version: Content-Transfer-Encoding; bh=29jW1T2Wde6r+b3ftLpzYibbW3UiM/6rVacZC5c/cNg=; b=HwW/QutNZlC1H44GVlOLRsdJo3w26aTwPQE2BKZYrh+qKvrwN95UhvgNI5mESK7MHjT7 UvEw56EzakoAPnekcyTrJo097hG+zOuG+pyGiJZahg5JgHUbdUxKFVItFzc1egtR/v4HE CP3w1/cuI3D8Sgo5rH9janDtTyhhL8xVqj/uVKjmQ1lYK9FeTXmSCxLNyfN6reGKENqPX Sh6PcTqJoOLGTB/neR+VsCn8ElkJ8SjVrJyFoITvINg13FSupv3d19reqNn/BuIOsGWxR L52PMHXi4obNxXBN5cECv6XzOmN8A1MG69x8DWeU7W+l0ReQHvq/emr79ifAEDW7Dog== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=intel.com; spf=pass smtp.mailfrom=intel.com; dkim=pass header.d=intel.com header.i=@intel.com header.a=rsa-sha256 header.s=Intel header.b=mJR7Ec3r; arc=none smtp.remote-ip=198.175.65.16 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.16]) (using TLSv1.2 with cipher ECDHE-ECDSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id CC960606A32C for ; Mon, 19 Oct 2026 20:50:59 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org CC960606A32C 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, unprotected) header.d=intel.com header.i=@intel.com header.a=rsa-sha256 header.s=Intel header.b=mJR7Ec3r DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1792443060; x=1823979060; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=dyMqtZ7sXS36KbsOSwN4WsIM147R1QE5b2xvHYSGPE8=; b=mJR7Ec3rcDXdJWRtgvQn6LMd896ew4gobetCPJPdsMcx7kYhAdqi2gZy h/n0bH+hWz0GCd1roG90uEE74x1wOOIjc0UT7la9MttvPlWKulsX7bFfS t0PYb62phY4szc+dJv447Bow2E8fsFvzj66bxIFF1m9Bqgyi6yoQvmHc8 WaZpnXKBeP8+46al+RS86zZ4yLCWpDz7JbtRTufVY/0iXTAhUMHA+/mJe SdtPda+ZvhY4OdtcORJD5zjAjv64lRnqYXlck97tM5ky1nGACWkEZ0PzC DyX1XAmO9+Hf8dsZrSpufYzY+jTq8U5nHoJtat6SydICZ35E3YG0cqliu g==; X-CSE-ConnectionGUID: v+CJPY1bT9Wm0Fol2wXDAg== X-CSE-MsgGUID: 4PtNVoS8SdOa8mJrxx+k/g== X-IronPort-AV: E=McAfee;i="6800,10657,11940"; a="1131270" X-IronPort-AV: E=Sophos;i="6.27,168,1787036400"; d="scan'208";a="1131270" Received: from fmviesa009.fm.intel.com ([10.60.135.149]) by orvoesa108.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 19 Oct 2026 13:50:51 -0700 X-CSE-ConnectionGUID: naJ6/7o1Q7mLDOsGiWu3IA== X-CSE-MsgGUID: gHcYs1cHQm+xwL2y1DyBbw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.27,168,1787036400"; d="scan'208";a="3008677" Received: from spandruv-mobl5.amr.corp.intel.com (HELO agluck-desk3.intel.com) ([10.124.220.87]) by smtpauth.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 19 Oct 2026 13:50:51 -0700 From: Tony Luck To: Fenghua Yu , Reinette Chatre , Maciej Wieczor-Retman , Peter Newman , James Morse , Babu Moger , Drew Fustini , Dave Martin , Chen Yu , David E Box , x86@kernel.org Cc: Christoph Hellwig , linux-kernel@vger.kernel.org, patches@lists.linux.dev, Tony Luck Subject: [PATCH v14 18/24] arm,x86,fs/resctrl: Enumerate AET on every resctrl mount Date: Mon, 19 Oct 2026 13:50:25 -0700 Message-ID: <20261019205031.16977-19-tony.luck@intel.com> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261019205031.16977-1-tony.luck@intel.com> References: <20261019205031.16977-1-tony.luck@intel.com> X-Mailing-List: patches@lists.linux.dev List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Application Energy Telemetry (AET) is enumerated only on the first mount of the resctrl file system. A successful enumeration takes a reference on the pmt_telemetry module that is never dropped. This is harmless only because AET support requires pmt_telemetry to be built in. In preparation for pmt_telemetry being built as a module, hold the module reference only while resctrl is mounted. resctrl must then enumerate AET on every mount and release everything obtained from pmt_telemetry on every unmount. Call resctrl_arch_pre_mount() on every mount attempt. Add resctrl_arch_unmount() for the architecture to undo it after a failed mount or on unmount. Serialize both hooks with each other and with the check that resctrl is not already mounted, so that enumeration only happens while resctrl is not mounted. Use a new mutex because the hooks take cpus_read_lock(), which nests outside rdtgroup_mutex. On x86, if AET was enumerated, unmount disables the AET events, returns the telemetry data to pmt_telemetry, drops the module reference and removes the AET monitoring domains. Cleanup at resctrl exit is no longer needed. Do not re-enable an event group that was disabled during mount because the system supports too few RMIDs for it. The same check would disable it again on the next mount. Signed-off-by: Tony Luck --- v14: New commit comment. aet_register_lock name changed to aet_lock. Babu: Add commit comment about event_group::force_off --- include/linux/resctrl.h | 10 +++++++-- arch/x86/kernel/cpu/resctrl/internal.h | 4 ++-- arch/x86/kernel/cpu/resctrl/core.c | 21 +++++++++++++++-- arch/x86/kernel/cpu/resctrl/intel_aet.c | 29 +++++++++++++++++++----- drivers/resctrl/mpam_resctrl.c | 4 ++++ fs/resctrl/rdtgroup.c | 30 ++++++++++++++++++++----- 6 files changed, 81 insertions(+), 17 deletions(-) diff --git a/include/linux/resctrl.h b/include/linux/resctrl.h index c77e24c0d8b6..c40d72e4a957 100644 --- a/include/linux/resctrl.h +++ b/include/linux/resctrl.h @@ -611,11 +611,17 @@ void resctrl_online_cpu(unsigned int cpu); void resctrl_offline_cpu(unsigned int cpu); /* - * Architecture hook called at beginning of first file system mount attempt. - * No locks are held. + * Architecture hook called at beginning of each file system mount attempt. + * Serialized against other mount and unmount attempts. */ void resctrl_arch_pre_mount(void); +/* + * Architecture hook called when mount fails, or on unmount. + * Serialized against other mount and unmount attempts. + */ +void resctrl_arch_unmount(void); + /** * resctrl_arch_rmid_read() - Read the eventid counter corresponding to rmid * for this resource and domain. diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h index 8406addc05f5..c66954bc01e7 100644 --- a/arch/x86/kernel/cpu/resctrl/internal.h +++ b/arch/x86/kernel/cpu/resctrl/internal.h @@ -234,15 +234,15 @@ void rdt_domain_reconfigure_cdp(struct rdt_resource *r); void resctrl_arch_mbm_cntr_assign_set_one(struct rdt_resource *r); #ifdef CONFIG_X86_CPU_RESCTRL_INTEL_AET -void __exit intel_aet_exit(void); bool intel_aet_pre_mount(void); +void intel_aet_unmount(void); int intel_aet_read_event(int domid, u32 rmid, void *arch_priv, u64 *val); void intel_aet_mon_domain_setup(int cpu, int id, struct rdt_resource *r, struct list_head *add_pos); bool intel_handle_aet_option(bool force_off, char *tok); #else -static inline void __exit intel_aet_exit(void) { } static inline bool intel_aet_pre_mount(void) { return false; } +static inline void intel_aet_unmount(void) { } static inline int intel_aet_read_event(int domid, u32 rmid, void *arch_priv, u64 *val) { return -EINVAL; diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c index ac67b4523b2d..40466f29e48e 100644 --- a/arch/x86/kernel/cpu/resctrl/core.c +++ b/arch/x86/kernel/cpu/resctrl/core.c @@ -811,6 +811,25 @@ void resctrl_arch_pre_mount(void) cpus_read_unlock(); } +void resctrl_arch_unmount(void) +{ + struct rdt_resource *r = &rdt_resources_all[RDT_RESOURCE_PERF_PKG].r_resctrl; + int cpu; + + if (!r->mon_capable) + return; + + intel_aet_unmount(); + + cpus_read_lock(); + mutex_lock(&domain_list_lock); + for_each_online_cpu(cpu) + domain_remove_cpu_mon(cpu, r); + r->mon_capable = false; + mutex_unlock(&domain_list_lock); + cpus_read_unlock(); +} + enum { RDT_FLAG_CMT, RDT_FLAG_MBM_TOTAL, @@ -1161,8 +1180,6 @@ late_initcall(resctrl_arch_late_init); static void __exit resctrl_arch_exit(void) { - intel_aet_exit(); - cpuhp_remove_state(rdt_online); resctrl_exit(); diff --git a/arch/x86/kernel/cpu/resctrl/intel_aet.c b/arch/x86/kernel/cpu/resctrl/intel_aet.c index 26406e18d5ed..75cd602d65ae 100644 --- a/arch/x86/kernel/cpu/resctrl/intel_aet.c +++ b/arch/x86/kernel/cpu/resctrl/intel_aet.c @@ -331,7 +331,7 @@ static enum pmt_feature_id lookup_pfid(const char *pfname) /* * Serialises AET's view of pmt_telemetry: - * - pmt_module, get_feature, put_feature + * - pmt_module, get_feature, put_feature, pmt_in_use * - every event_group's ->pfg * * Lock ordering with pmt/telemetry.c's ep_lock is ep_lock -> aet_lock. @@ -345,6 +345,11 @@ static struct module *pmt_module; static struct pmt_feature_group *(*get_feature)(enum pmt_feature_id id); static void (*put_feature)(struct pmt_feature_group *p); +/* + * Track whether pmt_telemetry enumeration succeeded during mount for use during unmount. + */ +static bool pmt_in_use; + /* * Request a copy of struct pmt_feature_group for each event group. If there is * one, the returned structure has an array of telemetry_region structures, @@ -429,19 +434,33 @@ bool intel_aet_pre_mount(void) return false; } + pmt_in_use = true; + return true; } -void __exit intel_aet_exit(void) +void intel_aet_unmount(void) { + struct rdt_resource *r = &rdt_resources_all[RDT_RESOURCE_PERF_PKG].r_resctrl; struct event_group **peg; + guard(mutex)(&aet_lock); + if (!pmt_in_use) + return; + for_each_event_group(peg) { - if ((*peg)->pfg) { - put_feature((*peg)->pfg); - (*peg)->pfg = NULL; + struct event_group *e = *peg; + + if (e->pfg) { + for (int i = 0; i < e->num_events; i++) + resctrl_disable_mon_event(e->evts[i].id); + put_feature(e->pfg); + e->pfg = NULL; } } + module_put(pmt_module); + pmt_in_use = false; + r->mon.num_rmid = 0; } #define DATA_VALID BIT_ULL(63) diff --git a/drivers/resctrl/mpam_resctrl.c b/drivers/resctrl/mpam_resctrl.c index 360a50eb0cd3..ecea2239afa4 100644 --- a/drivers/resctrl/mpam_resctrl.c +++ b/drivers/resctrl/mpam_resctrl.c @@ -121,6 +121,10 @@ void resctrl_arch_pre_mount(void) { } +void resctrl_arch_unmount(void) +{ +} + bool resctrl_arch_get_cdp_enabled(enum resctrl_res_level rid) { return mpam_resctrl_controls[rid].cdp_enabled; diff --git a/fs/resctrl/rdtgroup.c b/fs/resctrl/rdtgroup.c index ecdb5da50179..20e579067570 100644 --- a/fs/resctrl/rdtgroup.c +++ b/fs/resctrl/rdtgroup.c @@ -30,6 +30,9 @@ #include "internal.h" +/* Mutex protecting resctrl_mounted and mount/unmount operations */ +static DEFINE_MUTEX(resctrl_mount_lock); + /* Mutex to protect rdtgroup access. */ DEFINE_MUTEX(rdtgroup_mutex); @@ -48,7 +51,10 @@ LIST_HEAD(resctrl_schema_all); */ static LIST_HEAD(mon_data_kn_priv_list); -/* The filesystem can only be mounted once. */ +/* + * The filesystem can only be mounted once. Can only be updated + * while holding both resctrl_mount_lock and rdtgroup_mutex. + */ bool resctrl_mounted; /* Kernel fs node for "info" directory under root */ @@ -3147,6 +3153,7 @@ static void resctrl_unmount(void) { struct rdt_resource *r; + mutex_lock(&resctrl_mount_lock); cpus_read_lock(); mutex_lock(&rdtgroup_mutex); @@ -3164,6 +3171,8 @@ static void resctrl_unmount(void) resctrl_mounted = false; mutex_unlock(&rdtgroup_mutex); cpus_read_unlock(); + resctrl_arch_unmount(); + mutex_unlock(&resctrl_mount_lock); } static int rdt_get_tree(struct fs_context *fc) @@ -3175,24 +3184,27 @@ static int rdt_get_tree(struct fs_context *fc) struct rdt_resource *r; int ret; - DO_ONCE_SLEEPABLE(resctrl_arch_pre_mount); + mutex_lock(&resctrl_mount_lock); - cpus_read_lock(); - mutex_lock(&rdtgroup_mutex); /* * resctrl file system can only be mounted once. */ if (resctrl_mounted) { ret = -EBUSY; - goto out; + goto out_mount_unlock; } /* Avoid races from pending operations from a previous mount */ if (atomic_read(&rdtgroup_default.waitcount) != 0) { ret = -EBUSY; - goto out; + goto out_mount_unlock; } + resctrl_arch_pre_mount(); + + cpus_read_lock(); + mutex_lock(&rdtgroup_mutex); + if (!resctrl_alloc_capable() && !resctrl_mon_capable()) { ret = invalfc(fc, "No allocation or monitoring features are available or enabled"); goto out; @@ -3287,6 +3299,8 @@ static int rdt_get_tree(struct fs_context *fc) mutex_unlock(&rdtgroup_mutex); cpus_read_unlock(); + mutex_unlock(&resctrl_mount_lock); + ret = kernfs_get_tree(fc); /* * resctrl can only be mounted once, new superblock only expected @@ -3318,6 +3332,10 @@ static int rdt_get_tree(struct fs_context *fc) out: mutex_unlock(&rdtgroup_mutex); cpus_read_unlock(); + resctrl_arch_unmount(); +out_mount_unlock: + mutex_unlock(&resctrl_mount_lock); + return ret; } -- 2.56.0