Commit b42a3d7c authored by Mohit P. Tahiliani's avatar Mohit P. Tahiliani Committed by David S. Miller
Browse files

pie: improve comments and commenting style 



Improve the comments along with the commenting style used to
describe the members of the structures and their initial values
in the init functions.

Signed-off-by: default avatarMohit P. Tahiliani <tahiliani@nitk.edu.in>
Signed-off-by: default avatarLeslie Monis <lesliemonis@gmail.com>
Signed-off-by: default avatarGautam Ramakrishnan <gautamramk@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 2dfb1952

include/net/pie.h

+58 −27
Original line number Diff line number Diff line
@@ -14,42 +14,74 @@ 
#define DQCOUNT_INVALID	-1

#define PIE_SCALE	8



/* parameters used */

/**

 * struct pie_params - contains pie parameters

 * @target:		target delay in pschedtime

 * @tudpate:		interval at which drop probability is calculated

 * @limit:		total number of packets that can be in the queue

 * @alpha:		parameter to control drop probability

 * @beta:		parameter to control drop probability

 * @ecn:		is ECN marking of packets enabled

 * @bytemode:		is drop probability scaled based on pkt size

 * @dq_rate_estimator:	is Little's law used for qdelay calculation

 */

struct pie_params {

	psched_time_t target;	/* user specified target delay in pschedtime */

	u32 tupdate;		/* timer frequency (in jiffies) */

	u32 limit;		/* number of packets that can be enqueued */

	u32 alpha;		/* alpha and beta are between 0 and 32 */

	u32 beta;		/* and are used for shift relative to 1 */

	u8 ecn;			/* true if ecn is enabled */

	u8 bytemode;		/* to scale drop early prob based on pkt size */

	u8 dq_rate_estimator;	/* to calculate delay using Little's law */

	psched_time_t target;

	u32 tupdate;

	u32 limit;

	u32 alpha;

	u32 beta;

	u8 ecn;

	u8 bytemode;

	u8 dq_rate_estimator;

};



/* variables used */

/**

 * struct pie_vars - contains pie variables

 * @qdelay:			current queue delay

 * @qdelay_old:			queue delay in previous qdelay calculation

 * @burst_time:			burst time allowance

 * @dq_tstamp:			timestamp at which dq rate was last calculated

 * @prob:			drop probability

 * @accu_prob:			accumulated drop probability

 * @dq_count:			number of bytes dequeued in a measurement cycle

 * @avg_dq_rate:		calculated average dq rate

 * @qlen_old:			queue length during previous qdelay calculation

 * @accu_prob_overflows:	number of times accu_prob overflows

 */

struct pie_vars {

	psched_time_t qdelay;

	psched_time_t qdelay_old;

	psched_time_t burst_time;

	psched_time_t dq_tstamp;	/* drain rate */

	u64 prob;		/* probability but scaled by u64 limit. */

	u64 accu_prob;		/* accumulated drop probability */

	u64 dq_count;		/* measured in bytes */

	u32 avg_dq_rate;	/* bytes per pschedtime tick,scaled */

	u32 qlen_old;		/* in bytes */

	u8 accu_prob_overflows;	/* overflows of accu_prob */

	psched_time_t dq_tstamp;

	u64 prob;

	u64 accu_prob;

	u64 dq_count;

	u32 avg_dq_rate;

	u32 qlen_old;

	u8 accu_prob_overflows;

};



/* statistics gathering */

/**

 * struct pie_stats - contains pie stats

 * @packets_in:	total number of packets enqueued

 * @dropped:	packets dropped due to pie action

 * @overlimit:	packets dropped due to lack of space in queue

 * @ecn_mark:	packets marked with ECN

 * @maxq:	maximum queue size

 */

struct pie_stats {

	u32 packets_in;		/* total number of packets enqueued */

	u32 dropped;		/* packets dropped due to pie_action */

	u32 overlimit;		/* dropped due to lack of space in queue */

	u32 ecn_mark;		/* packets marked with ECN */

	u32 maxq;		/* maximum queue size */

	u32 packets_in;

	u32 dropped;

	u32 overlimit;

	u32 ecn_mark;

	u32 maxq;

};



/* private skb vars */

/**

 * struct pie_skb_cb - contains private skb vars

 * @enqueue_time:	timestamp when the packet is enqueued

 */

struct pie_skb_cb {

	psched_time_t enqueue_time;

};
@@ -58,7 +90,7 @@ static inline void pie_params_init(struct pie_params *params) 
{

	params->target = PSCHED_NS2TICKS(15 * NSEC_PER_MSEC);	/* 15 ms */

	params->tupdate = usecs_to_jiffies(15 * USEC_PER_MSEC);	/* 15 ms */

	params->limit = 1000;	/* default of 1000 packets */

	params->limit = 1000;

	params->alpha = 2;

	params->beta = 20;

	params->ecn = false;
@@ -68,8 +100,7 @@ static inline void pie_params_init(struct pie_params *params) 


static inline void pie_vars_init(struct pie_vars *vars)

{

	/* default of 150 ms in pschedtime */

	vars->burst_time = PSCHED_NS2TICKS(150 * NSEC_PER_MSEC);

	vars->burst_time = PSCHED_NS2TICKS(150 * NSEC_PER_MSEC); /* 150 ms */

	vars->dq_tstamp = DTIME_INVALID;

	vars->accu_prob = 0;

	vars->dq_count = DQCOUNT_INVALID;