[dpdk-dev] [PATCH 1/4] power: fix non thread-safe power env modification

Hajkowski marcinx.hajkowski at intel.com
Wed Mar 13 20:48:41 CET 2019


From: Marcin Hajkowski <marcinx.hajkowski at intel.com>

Due to lack of thread safety in exisiting solution
use spinlock mechanism for atomic
modification of power environment related data.

Fixes: 445c6528b5 ("power: common interface for guest and host")
Cc: stable at dpdk.org

Signed-off-by: Marcin Hajkowski <marcinx.hajkowski at intel.com>
---
 doc/guides/rel_notes/release_19_05.rst |  2 ++
 lib/librte_power/rte_power.c           | 30 ++++++++++++++++++--------
 lib/librte_power/rte_power.h           |  2 +-
 3 files changed, 24 insertions(+), 10 deletions(-)

diff --git a/doc/guides/rel_notes/release_19_05.rst b/doc/guides/rel_notes/release_19_05.rst
index 61a2c7383..65371e4c8 100644
--- a/doc/guides/rel_notes/release_19_05.rst
+++ b/doc/guides/rel_notes/release_19_05.rst
@@ -120,6 +120,8 @@ API Changes
    Also, make sure to start the actual text at the margin.
    =========================================================
 
+   * power: ``rte_power_set_env`` and ``rte_power_unset_env`` functions
+     have been modified to be thread safe.
 
 ABI Changes
 -----------
diff --git a/lib/librte_power/rte_power.c b/lib/librte_power/rte_power.c
index a05fbef94..540d69be7 100644
--- a/lib/librte_power/rte_power.c
+++ b/lib/librte_power/rte_power.c
@@ -2,7 +2,7 @@
  * Copyright(c) 2010-2014 Intel Corporation
  */
 
-#include <rte_atomic.h>
+#include <rte_spinlock.h>
 
 #include "rte_power.h"
 #include "power_acpi_cpufreq.h"
@@ -12,7 +12,7 @@
 
 enum power_management_env global_default_env = PM_ENV_NOT_SET;
 
-volatile uint32_t global_env_cfg_status = 0;
+static rte_spinlock_t global_env_cfg_lock = RTE_SPINLOCK_INITIALIZER;
 
 /* function pointers */
 rte_power_freqs_t rte_power_freqs  = NULL;
@@ -30,9 +30,15 @@ rte_power_get_capabilities_t rte_power_get_capabilities;
 int
 rte_power_set_env(enum power_management_env env)
 {
-	if (rte_atomic32_cmpset(&global_env_cfg_status, 0, 1) == 0) {
+	rte_spinlock_lock(&global_env_cfg_lock);
+
+	if (global_default_env != PM_ENV_NOT_SET) {
+		rte_spinlock_unlock(&global_env_cfg_lock);
 		return 0;
 	}
+
+	int ret = 0;
+
 	if (env == PM_ENV_ACPI_CPUFREQ) {
 		rte_power_freqs = power_acpi_cpufreq_freqs;
 		rte_power_get_freq = power_acpi_cpufreq_get_freq;
@@ -73,18 +79,24 @@ rte_power_set_env(enum power_management_env env)
 	} else {
 		RTE_LOG(ERR, POWER, "Invalid Power Management Environment(%d) set\n",
 				env);
-		rte_power_unset_env();
-		return -1;
+		ret = -1;
 	}
-	global_default_env = env;
-	return 0;
+
+	if (ret == 0)
+		global_default_env = env;
+	else
+		global_default_env = PM_ENV_NOT_SET;
+
+	rte_spinlock_unlock(&global_env_cfg_lock);
+	return ret;
 }
 
 void
 rte_power_unset_env(void)
 {
-	if (rte_atomic32_cmpset(&global_env_cfg_status, 1, 0) != 0)
-		global_default_env = PM_ENV_NOT_SET;
+	rte_spinlock_lock(&global_env_cfg_lock);
+	global_default_env = PM_ENV_NOT_SET;
+	rte_spinlock_unlock(&global_env_cfg_lock);
 }
 
 enum power_management_env
diff --git a/lib/librte_power/rte_power.h b/lib/librte_power/rte_power.h
index c5e8f6b5b..54b76b4ee 100644
--- a/lib/librte_power/rte_power.h
+++ b/lib/librte_power/rte_power.h
@@ -26,7 +26,7 @@ enum power_management_env {PM_ENV_NOT_SET, PM_ENV_ACPI_CPUFREQ, PM_ENV_KVM_VM,
 /**
  * Set the default power management implementation. If this is not called prior
  * to rte_power_init(), then auto-detect of the environment will take place.
- * It is not thread safe.
+ * It is thread safe.
  *
  * @param env
  *  env. The environment in which to initialise Power Management for.
-- 
2.17.2

--------------------------------------------------------------
Intel Research and Development Ireland Limited
Registered in Ireland
Registered Office: Collinstown Industrial Park, Leixlip, County Kildare
Registered Number: 308263


This e-mail and any attachments may contain confidential material for the sole
use of the intended recipient(s). Any review or distribution by others is
strictly prohibited. If you are not the intended recipient, please contact the
sender and delete all copies.



More information about the dev mailing list