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pie: improve comments and commenting style

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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: Mohit P. Tahiliani <tahiliani@nitk.edu.in>
Signed-off-by: Leslie Monis <lesliemonis@gmail.com>
Signed-off-by: Gautam Ramakrishnan <gautamramk@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Mohit P. Tahiliani 2020-01-22 23:52:29 +05:30 committed by David S. Miller
parent 2dfb1952a9
commit b42a3d7c7c
1 changed files with 58 additions and 27 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

85
include/net/pie.h
View file

@ -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;