linux-kernel - [PATCH 20/32] x86/intel/cqm: use PERF_CGROUP_NO

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <1461905018-86355-21-git-send-email-davidcc@google.com>
Date:	Thu, 28 Apr 2016 21:43:26 -0700
From:	David Carrillo-Cisneros <davidcc@...gle.com>
To:	Peter Zijlstra <peterz@...radead.org>,
	Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
	Arnaldo Carvalho de Melo <acme@...nel.org>,
	Ingo Molnar <mingo@...hat.com>
Cc:	Vikas Shivappa <vikas.shivappa@...ux.intel.com>,
	Matt Fleming <matt.fleming@...el.com>,
	Tony Luck <tony.luck@...el.com>,
	Stephane Eranian <eranian@...gle.com>,
	Paul Turner <pjt@...gle.com>,
	David Carrillo-Cisneros <davidcc@...gle.com>, x86@...nel.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH 20/32] x86/intel/cqm: use PERF_CGROUP_NO_RECURSION in CQM

The CQM hardware is not compatible with the way generic code handles
cgroup hierarchies (simultaneously adding the events of for all ancestors
of the current cgroup). This version of Intel's CQM driver handles
cgroup hierarchy internally.

Set PERF_CGROUP_NO_RECURSION for llc_occupancy events to
signal perf's generic code to not add events for ancestors of current
cgroup.

Reviewed-by: Stephane Eranian <eranian@...gle.com>
Signed-off-by: David Carrillo-Cisneros <davidcc@...gle.com>
---
 arch/x86/events/intel/cqm.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/arch/x86/events/intel/cqm.c b/arch/x86/events/intel/cqm.c
index dcf7f4a..d8d3191 100644
--- a/arch/x86/events/intel/cqm.c
+++ b/arch/x86/events/intel/cqm.c
@@ -2489,6 +2489,14 @@ static int intel_cqm_event_init(struct perf_event *event)
 	INIT_LIST_HEAD(&event->hw.cqm_event_groups_entry);
 	INIT_LIST_HEAD(&event->hw.cqm_event_group_entry);
 
+	/*
+	 * CQM driver handles cgroup recursion and since only noe
+	 * RMID can be programmed at the time in each core, then
+	 * it is incompatible with the way generic code handles
+	 * cgroup hierarchies.
+	 */
+	event->pmu_event_flags |= PERF_CGROUP_NO_RECURSION;
+
 	mutex_lock(&cqm_mutex);
 
 
-- 
2.8.0.rc3.226.g39d4020