From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.12]) (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 7761C3FE357 for ; Wed, 29 Apr 2026 18:49:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.12 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777488564; cv=none; b=Tgf1+BDpKrCJQ8gAlMyFfUlFCQ2coGzuBv0TUiYp7ADiWHECNjUfp8Gd+xf+TphJzPnC7Yi722hDeo2C+i6uUGpUGvtIJXrprG3tgLkbHxKscosYgrjJ5/0oeQmjlNHOKi7bT8DAvHU/5SWtZrlRIpOt6wYAemYmFmf71Rg0PwM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777488564; c=relaxed/simple; bh=gDithhGK9/jeLzYM5a2BxEcbR65W2GtKgeDaTht9ynM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=NIEEz3MBvJd4TfQlAMo6onbbmjyhjYFmL7StCXZgihjwFNug/uaJaLyrb5EhlD79jhBzjAyt5E3Hui1ED2L7AvUrC0kXLKUUFXDL7PFvKCtPd5jooK80ImgVTZ8dAEbbDSKhTTXfxjBmUAQB7axPYPxsDCy+f1aCnXW6g3vwymA= 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=BDpnhNDN; arc=none smtp.client-ip=198.175.65.12 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="BDpnhNDN" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1777488560; x=1809024560; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=gDithhGK9/jeLzYM5a2BxEcbR65W2GtKgeDaTht9ynM=; b=BDpnhNDNm8Jg7uHpfxk0G3W/USDGLQqOFVNv2YrMhEa+gymAjjMD1YPI M80bQKWPUxXRx8mYN2JzvJaSVdPJspTju8D87Z99IY+iFQh9ImYd+bZVo psRGssnLdbvCumkCanwIztvo1X11W1l8lwtZFp1XeiHpYGyIeSBeL2QNn dIDt8p7ZcbgFJM96KnZX9jEnIYqhdz99wtchCI/BjiU6IZlWwKK92YrHv OhN4iny3YAxB+w/Ft/EtoTmgYtmDQ72DHlWaaBUUt1sI9ka3M+Ef5XeHp QyiMj4I6K+QnyxDcu5BijtlZuyw7DZEDWjg1YdoB0nXRJYprLiUwzVEbq Q==; X-CSE-ConnectionGUID: jHZFcgXJSnGPscoPjNZ54A== X-CSE-MsgGUID: NrmFVgFHSfK0lIBS2ZLQSg== X-IronPort-AV: E=McAfee;i="6800,10657,11771"; a="89890742" X-IronPort-AV: E=Sophos;i="6.23,206,1770624000"; d="scan'208";a="89890742" Received: from orviesa003.jf.intel.com ([10.64.159.143]) by orvoesa104.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 29 Apr 2026 11:49:08 -0700 X-CSE-ConnectionGUID: lkKQ2L09RS6D/oGh+GlxkA== X-CSE-MsgGUID: B5rmDV8pT3iJT7ROA80J/g== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.23,206,1770624000"; d="scan'208";a="238323029" Received: from mjruhl-desk.amr.corp.intel.com (HELO agluck-desk3.home.arpa) ([10.124.222.13]) by ORVIESA003-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 29 Apr 2026 11:49:08 -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 v6 07/10] x86/resctrl: Resolve INTEL_PMT_TELEMETRY symbols at runtime Date: Wed, 29 Apr 2026 11:48:55 -0700 Message-ID: <20260429184858.36423-8-tony.luck@intel.com> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260429184858.36423-1-tony.luck@intel.com> References: <20260429184858.36423-1-tony.luck@intel.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit resctrl is always built-in, but INTEL_PMT_TELEMETRY and INTEL_TPMI are logically independent and should be loadable modules. Switch AET to use the function-pointer registration API (introduced in the preceding patch) instead of direct link-time references to PMT symbols. Move AET enumeration into resctrl_arch_pre_mount() and cleanup into resctrl_arch_unmount() so the PMT module can be unloaded whenever the filesystem is not mounted. Because all cleanup now happens in the unmount path, intel_aet_exit() is no longer needed and is removed. Note that the Linux file system code does not serialize calls to fs_context_operations::get_tree(), so there may be arbitrarily many parallel calls if users invoke mount(2) multiple times. Add locking and state (resctrl_arch_mount_entries) to only perform enumeration of first mount, and cleanup on last unmount. event_group::num_rmid may be reset (reduced) during enumeration. This is not worth resetting on unmount because the same reduction would occur on each subsequent mount. Signed-off-by: Tony Luck --- include/linux/resctrl.h | 3 ++ arch/x86/kernel/cpu/resctrl/internal.h | 8 ++--- arch/x86/kernel/cpu/resctrl/core.c | 41 +++++++++++++++++++++++-- arch/x86/kernel/cpu/resctrl/intel_aet.c | 26 ++++++++++++---- 4 files changed, 65 insertions(+), 13 deletions(-) diff --git a/include/linux/resctrl.h b/include/linux/resctrl.h index 3705f0214fa6..9534d42e0c57 100644 --- a/include/linux/resctrl.h +++ b/include/linux/resctrl.h @@ -557,6 +557,9 @@ void resctrl_offline_cpu(unsigned int cpu); */ void resctrl_arch_pre_mount(void); +/* Called to report unmount. */ +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 3b09cfe9a046..017a19143ec9 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 -bool intel_aet_get_events(void); -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 bool intel_aet_get_events(void) { return false; } -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 934492c7e643..9336299b9647 100644 --- a/arch/x86/kernel/cpu/resctrl/core.c +++ b/arch/x86/kernel/cpu/resctrl/core.c @@ -16,10 +16,12 @@ #define pr_fmt(fmt) "resctrl: " fmt +#include #include #include #include #include +#include #include #include @@ -776,12 +778,20 @@ static int resctrl_arch_offline_cpu(unsigned int cpu) return 0; } +static DEFINE_MUTEX(resctrl_arch_mount_lock); +static int resctrl_arch_mount_entries; + void resctrl_arch_pre_mount(void) { struct rdt_resource *r = &rdt_resources_all[RDT_RESOURCE_PERF_PKG].r_resctrl; int cpu; - if (!intel_aet_get_events()) + guard(mutex)(&resctrl_arch_mount_lock); + + if (++resctrl_arch_mount_entries > 1) + return; + + if (!intel_aet_pre_mount()) return; /* @@ -798,6 +808,33 @@ 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; + + guard(mutex)(&resctrl_arch_mount_lock); + + if (--resctrl_arch_mount_entries > 0) + return; + + WARN_ON(resctrl_arch_mount_entries < 0); + + intel_aet_unmount(); + + if (!r->mon_capable) + return; + + cpus_read_lock(); + mutex_lock(&domain_list_lock); + for_each_online_cpu(cpu) + domain_remove_cpu_mon(cpu, r); + r->mon_capable = false; + rdt_mon_feature_count--; + mutex_unlock(&domain_list_lock); + cpus_read_unlock(); +} + enum { RDT_FLAG_CMT, RDT_FLAG_MBM_TOTAL, @@ -1174,8 +1211,6 @@ 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 2b3677783427..6e7458a722f9 100644 --- a/arch/x86/kernel/cpu/resctrl/intel_aet.c +++ b/arch/x86/kernel/cpu/resctrl/intel_aet.c @@ -25,8 +25,8 @@ #include #include #include -#include #include +#include #include #include #include @@ -307,7 +307,7 @@ static void (*put_feature)(struct pmt_feature_group *p); * struct pmt_feature_group to indicate that its events are successfully * enabled. */ -bool intel_aet_get_events(void) +static bool aet_get_events(void) { struct pmt_feature_group *p; enum pmt_feature_id pfid; @@ -316,14 +316,14 @@ bool intel_aet_get_events(void) for_each_event_group(peg) { pfid = lookup_pfid((*peg)->pfname); - p = intel_pmt_get_regions_by_feature(pfid); + p = get_feature(pfid); if (IS_ERR_OR_NULL(p)) continue; if (enable_events(*peg, p)) { (*peg)->pfg = p; ret = true; } else { - intel_pmt_put_feature_group(p); + put_feature(p); } } @@ -349,13 +349,27 @@ void intel_aet_unregister_enumeration(void) } EXPORT_SYMBOL_GPL(intel_aet_unregister_enumeration); -void __exit intel_aet_exit(void) +bool intel_aet_pre_mount(void) +{ + guard(mutex)(&aet_register_lock); + if (!get_feature || !put_feature) + return false; + + return aet_get_events(); +} + +void intel_aet_unmount(void) { struct event_group **peg; + guard(mutex)(&aet_register_lock); for_each_event_group(peg) { if ((*peg)->pfg) { - intel_pmt_put_feature_group((*peg)->pfg); + struct event_group *e = *peg; + + for (int j = 0; j < e->num_events; j++) + resctrl_disable_mon_event(e->evts[j].id); + put_feature((*peg)->pfg); (*peg)->pfg = NULL; } } -- 2.53.0