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From: Cody P Schafer <cody@linux.vnet.ibm.com>
To: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>,
	Peter Zijlstra <peterz@infradead.org>,
	Paul Mackerras <paulus@samba.org>, Ingo Molnar <mingo@redhat.com>
Cc: LKML <linux-kernel@vger.kernel.org>,
	Cody P Schafer <cody@linux.vnet.ibm.com>
Subject: [PATCH 1/3] perf: comment on usage of perf_invalid_context
Date: Thu,  9 Jan 2014 15:51:30 -0800	[thread overview]
Message-ID: <1389311492-5059-2-git-send-email-cody@linux.vnet.ibm.com> (raw)
In-Reply-To: <1389311492-5059-1-git-send-email-cody@linux.vnet.ibm.com>

Context numbers less than 0 are treated specially within the events
code, add a comment to document this.

Signed-off-by: Cody P Schafer <cody@linux.vnet.ibm.com>
---
 include/linux/sched.h | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/include/linux/sched.h b/include/linux/sched.h
index 53f97eb..f574820 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1033,6 +1033,10 @@ struct sched_rt_entity {
 struct rcu_node;
 
 enum perf_event_task_context {
+	/*
+	 * When <0, allocate a pmu local pmu->pmu_cpu_context (instead
+	 * of sharing among pmus in the same context) and forbid task tracking.
+	 */
 	perf_invalid_context = -1,
 	perf_hw_context = 0,
 	perf_sw_context,
-- 
1.8.5.2


  reply	other threads:[~2014-01-09 23:52 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-01-09 23:51 [PATCH 0/3] perf: note task_ctx_nr < 0 and sw event merging behavior Cody P Schafer
2014-01-09 23:51 ` Cody P Schafer [this message]
2014-01-10  9:34   ` [PATCH 1/3] perf: comment on usage of perf_invalid_context Peter Zijlstra
2014-01-09 23:51 ` [PATCH 2/3] perf: clarify comment regarding event merging Cody P Schafer
2014-01-10  9:36   ` Peter Zijlstra
2014-01-13 21:21     ` Cody P Schafer
2014-01-09 23:51 ` [PATCH 3/3] perf: clarify comment regarding perf_pmu_contexts Cody P Schafer
2014-01-10  9:37   ` Peter Zijlstra

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