From 536a0d8e79fb928f2735db37dda95682b6754f9a Mon Sep 17 00:00:00 2001 From: Xiaochen Shen Date: Thu, 12 Dec 2019 04:05:05 +0800 Subject: x86/resctrl: Check monitoring static key in the MBM overflow handler Currently, there are three static keys in the resctrl file system: rdt_mon_enable_key and rdt_alloc_enable_key indicate if the monitoring feature and the allocation feature are enabled, respectively. The rdt_enable_key is enabled when either the monitoring feature or the allocation feature is enabled. If no monitoring feature is present (either hardware doesn't support a monitoring feature or the feature is disabled by the kernel command line option "rdt="), rdt_enable_key is still enabled but rdt_mon_enable_key is disabled. MBM is a monitoring feature. The MBM overflow handler intends to check if the monitoring feature is not enabled for fast return. So check the rdt_mon_enable_key in it instead of the rdt_enable_key as former is the more accurate check. [ bp: Massage commit message. ] Fixes: e33026831bdb ("x86/intel_rdt/mbm: Handle counter overflow") Signed-off-by: Xiaochen Shen Signed-off-by: Borislav Petkov Link: https://lkml.kernel.org/r/1576094705-13660-1-git-send-email-xiaochen.shen@intel.com --- arch/x86/kernel/cpu/resctrl/monitor.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'arch/x86/kernel/cpu/resctrl/monitor.c') diff --git a/arch/x86/kernel/cpu/resctrl/monitor.c b/arch/x86/kernel/cpu/resctrl/monitor.c index 397206f23d14..773124b0e18a 100644 --- a/arch/x86/kernel/cpu/resctrl/monitor.c +++ b/arch/x86/kernel/cpu/resctrl/monitor.c @@ -514,7 +514,7 @@ void mbm_handle_overflow(struct work_struct *work) mutex_lock(&rdtgroup_mutex); - if (!static_branch_likely(&rdt_enable_key)) + if (!static_branch_likely(&rdt_mon_enable_key)) goto out_unlock; d = get_domain_from_cpu(cpu, &rdt_resources_all[RDT_RESOURCE_L3]); @@ -543,7 +543,7 @@ void mbm_setup_overflow_handler(struct rdt_domain *dom, unsigned long delay_ms) unsigned long delay = msecs_to_jiffies(delay_ms); int cpu; - if (!static_branch_likely(&rdt_enable_key)) + if (!static_branch_likely(&rdt_mon_enable_key)) return; cpu = cpumask_any(&dom->cpu_mask); dom->mbm_work_cpu = cpu; -- cgit v1.2.3-70-g09d2