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Commit da8ebe4e authored by Jean Delvare's avatar Jean Delvare Committed by Jean Delvare
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hwmon: (ibmaem) Avoid repeated memory allocations 



Preallocate a buffer for the response to sensor reads, and reuse it
for each read instead of allocating a new one each time. This should
be faster and should also avoid memory fragmentation.

Signed-off-by: default avatarJean Delvare <khali@linux-fr.org>
Acked-by: default avatarDarrick J. Wong <djwong@us.ibm.com>
Acked-by: default avatarGuenter Roeck <guenter.roeck@ericsson.com>
parent 9d84c9e8

drivers/hwmon/ibmaem.c

+20 −8
Original line number Diff line number Diff line
@@ -147,8 +147,9 @@ struct aem_data { 
	int			id;

	struct aem_ipmi_data	ipmi;



	/* Function to update sensors */

	/* Function and buffer to update sensors */

	void (*update)(struct aem_data *data);

	struct aem_read_sensor_resp *rs_resp;



	/*

	 * AEM 1.x sensors:
@@ -355,13 +356,14 @@ static void aem_msg_handler(struct ipmi_recv_msg *msg, void *user_msg_data) 


/* Sensor support functions */



/* Read a sensor value */

/* Read a sensor value; must be called with data->lock held */

static int aem_read_sensor(struct aem_data *data, u8 elt, u8 reg,

			   void *buf, size_t size)

{

	int rs_size, res;

	struct aem_read_sensor_req rs_req;

	struct aem_read_sensor_resp *rs_resp;

	/* Use preallocated rx buffer */

	struct aem_read_sensor_resp *rs_resp = data->rs_resp;

	struct aem_ipmi_data *ipmi = &data->ipmi;



	/* AEM registers are 1, 2, 4 or 8 bytes */
@@ -387,10 +389,6 @@ static int aem_read_sensor(struct aem_data *data, u8 elt, u8 reg, 
	ipmi->tx_message.data_len = sizeof(rs_req);



	rs_size = sizeof(*rs_resp) + size;

	rs_resp = kzalloc(rs_size, GFP_KERNEL);

	if (!rs_resp)

		return -ENOMEM;



	ipmi->rx_msg_data = rs_resp;

	ipmi->rx_msg_len = rs_size;
@@ -433,7 +431,6 @@ static int aem_read_sensor(struct aem_data *data, u8 elt, u8 reg, 
	res = 0;



out:

	kfree(rs_resp);

	return res;

}
@@ -491,6 +488,7 @@ static void aem_delete(struct aem_data *data) 
{

	list_del(&data->list);

	aem_remove_sensors(data);

	kfree(data->rs_resp);

	hwmon_device_unregister(data->hwmon_dev);

	ipmi_destroy_user(data->ipmi.user);

	platform_set_drvdata(data->pdev, NULL);
@@ -584,6 +582,11 @@ static int aem_init_aem1_inst(struct aem_ipmi_data *probe, u8 module_handle) 
	}



	data->update = update_aem1_sensors;

	data->rs_resp = kzalloc(sizeof(*(data->rs_resp)) + 8, GFP_KERNEL);

	if (!data->rs_resp) {

		res = -ENOMEM;

		goto alloc_resp_err;

	}



	/* Find sensors */

	res = aem1_find_sensors(data);
@@ -599,6 +602,8 @@ static int aem_init_aem1_inst(struct aem_ipmi_data *probe, u8 module_handle) 
	return 0;



sensor_err:

	kfree(data->rs_resp);

alloc_resp_err:

	hwmon_device_unregister(data->hwmon_dev);

hwmon_reg_err:

	ipmi_destroy_user(data->ipmi.user);
@@ -717,6 +722,11 @@ static int aem_init_aem2_inst(struct aem_ipmi_data *probe, 
	}



	data->update = update_aem2_sensors;

	data->rs_resp = kzalloc(sizeof(*(data->rs_resp)) + 8, GFP_KERNEL);

	if (!data->rs_resp) {

		res = -ENOMEM;

		goto alloc_resp_err;

	}



	/* Find sensors */

	res = aem2_find_sensors(data);
@@ -732,6 +742,8 @@ static int aem_init_aem2_inst(struct aem_ipmi_data *probe, 
	return 0;



sensor_err:

	kfree(data->rs_resp);

alloc_resp_err:

	hwmon_device_unregister(data->hwmon_dev);

hwmon_reg_err:

	ipmi_destroy_user(data->ipmi.user);