+/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
* Header file for the BFQ I/O scheduler: data structures and
* prototypes of interface functions among BFQ components.
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License as
- * published by the Free Software Foundation; either version 2 of the
- * License, or (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- * General Public License for more details.
*/
#ifndef _BFQ_H
#define _BFQ_H
#define BFQ_DEFAULT_GRP_IOPRIO 0
#define BFQ_DEFAULT_GRP_CLASS IOPRIO_CLASS_BE
+#define MAX_PID_STR_LENGTH 12
+
/*
* Soft real-time applications are extremely more latency sensitive
* than interactive ones. Over-raise the weight of the former to
* expiration. This peculiar definition allows for the following
* optimization, not yet exploited: while a given entity is still in
* service, we already know which is the best candidate for next
- * service among the other active entitities in the same parent
+ * service among the other active entities in the same parent
* entity. We can then quickly compare the timestamps of the
* in-service entity with those of such best candidate.
*
*
* Unless cgroups are used, the weight value is calculated from the
* ioprio to export the same interface as CFQ. When dealing with
- * ``well-behaved'' queues (i.e., queues that do not spend too much
+ * "well-behaved" queues (i.e., queues that do not spend too much
* time to consume their budget and have true sequential behavior, and
* when there are no external factors breaking anticipation) the
* relative weights at each level of the cgroups hierarchy should be
/* next ioprio and ioprio class if a change is in progress */
unsigned short new_ioprio, new_ioprio_class;
+ /* last total-service-time sample, see bfq_update_inject_limit() */
+ u64 last_serv_time_ns;
+ /* limit for request injection */
+ unsigned int inject_limit;
+ /* last time the inject limit has been decreased, in jiffies */
+ unsigned long decrease_time_jif;
+
/*
* Shared bfq_queue if queue is cooperating with one or more
* other queues.
/* max service rate measured so far */
u32 max_service_rate;
- /*
- * Ratio between the service received by bfqq while it is in
- * service, and the cumulative service (of requests of other
- * queues) that may be injected while bfqq is empty but still
- * in service. To increase precision, the coefficient is
- * measured in tenths of unit. Here are some example of (1)
- * ratios, (2) resulting percentages of service injected
- * w.r.t. to the total service dispatched while bfqq is in
- * service, and (3) corresponding values of the coefficient:
- * 1 (50%) -> 10
- * 2 (33%) -> 20
- * 10 (9%) -> 100
- * 9.9 (9%) -> 99
- * 1.5 (40%) -> 15
- * 0.5 (66%) -> 5
- * 0.1 (90%) -> 1
- *
- * So, if the coefficient is lower than 10, then
- * injected service is more than bfqq service.
- */
- unsigned int inject_coeff;
- /* amount of service injected in current service slot */
- unsigned int injected_service;
};
/**
*/
bool was_in_burst_list;
+ /*
+ * Save the weight when a merge occurs, to be able
+ * to restore it in case of split. If the weight is not
+ * correctly resumed when the queue is recycled,
+ * then the weight of the recycled queue could differ
+ * from the weight of the original queue.
+ */
+ unsigned int saved_weight;
+
/*
* Similar to previous fields: save wr information.
*/
* weight-raised @bfq_queue (see the comments to the functions
* bfq_weights_tree_[add|remove] for further details).
*/
- struct rb_root queue_weights_tree;
+ struct rb_root_cached queue_weights_tree;
/*
* Number of groups with at least one descendant process that
/* number of requests dispatched and waiting for completion */
int rq_in_driver;
+ /* true if the device is non rotational and performs queueing */
+ bool nonrot_with_queueing;
+
/*
* Maximum number of requests in driver in the last
* @hw_tag_samples completed requests.
/* time of last request completion (ns) */
u64 last_completion;
+ /* time of last transition from empty to non-empty (ns) */
+ u64 last_empty_occupied_ns;
+
+ /*
+ * Flag set to activate the sampling of the total service time
+ * of a just-arrived first I/O request (see
+ * bfq_update_inject_limit()). This will cause the setting of
+ * waited_rq when the request is finally dispatched.
+ */
+ bool wait_dispatch;
+ /*
+ * If set, then bfq_update_inject_limit() is invoked when
+ * waited_rq is eventually completed.
+ */
+ struct request *waited_rq;
+ /*
+ * True if some request has been injected during the last service hole.
+ */
+ bool rqs_injected;
+
/* time of first rq dispatch in current observation interval (ns) */
u64 first_dispatch;
/* time of last rq dispatch in current observation interval (ns) */
ktime_t last_budget_start;
/* beginning of the last idle slice */
ktime_t last_idling_start;
+ unsigned long last_idling_start_jiffies;
/* number of samples in current observation interval */
int peak_rate_samples;
struct bfq_data *bic_to_bfqd(struct bfq_io_cq *bic);
void bfq_pos_tree_add_move(struct bfq_data *bfqd, struct bfq_queue *bfqq);
void bfq_weights_tree_add(struct bfq_data *bfqd, struct bfq_queue *bfqq,
- struct rb_root *root);
+ struct rb_root_cached *root);
void __bfq_weights_tree_remove(struct bfq_data *bfqd,
struct bfq_queue *bfqq,
- struct rb_root *root);
+ struct rb_root_cached *root);
void bfq_weights_tree_remove(struct bfq_data *bfqd,
struct bfq_queue *bfqq);
void bfq_bfqq_expire(struct bfq_data *bfqd, struct bfq_queue *bfqq,
/* --------------- end of interface of B-WF2Q+ ---------------- */
/* Logging facilities. */
+static inline void bfq_pid_to_str(int pid, char *str, int len)
+{
+ if (pid != -1)
+ snprintf(str, len, "%d", pid);
+ else
+ snprintf(str, len, "SHARED-");
+}
+
#ifdef CONFIG_BFQ_GROUP_IOSCHED
struct bfq_group *bfqq_group(struct bfq_queue *bfqq);
#define bfq_log_bfqq(bfqd, bfqq, fmt, args...) do { \
+ char pid_str[MAX_PID_STR_LENGTH]; \
+ bfq_pid_to_str((bfqq)->pid, pid_str, MAX_PID_STR_LENGTH); \
blk_add_cgroup_trace_msg((bfqd)->queue, \
bfqg_to_blkg(bfqq_group(bfqq))->blkcg, \
- "bfq%d%c " fmt, (bfqq)->pid, \
+ "bfq%s%c " fmt, pid_str, \
bfq_bfqq_sync((bfqq)) ? 'S' : 'A', ##args); \
} while (0)
#else /* CONFIG_BFQ_GROUP_IOSCHED */
-#define bfq_log_bfqq(bfqd, bfqq, fmt, args...) \
- blk_add_trace_msg((bfqd)->queue, "bfq%d%c " fmt, (bfqq)->pid, \
+#define bfq_log_bfqq(bfqd, bfqq, fmt, args...) do { \
+ char pid_str[MAX_PID_STR_LENGTH]; \
+ bfq_pid_to_str((bfqq)->pid, pid_str, MAX_PID_STR_LENGTH); \
+ blk_add_trace_msg((bfqd)->queue, "bfq%s%c " fmt, pid_str, \
bfq_bfqq_sync((bfqq)) ? 'S' : 'A', \
- ##args)
+ ##args); \
+} while (0)
#define bfq_log_bfqg(bfqd, bfqg, fmt, args...) do {} while (0)
#endif /* CONFIG_BFQ_GROUP_IOSCHED */
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