* [PATCH 1/3] cfq-iosched: Convert from jiffies to nanoseconds
2016-06-08 13:11 [PATCH 0/3 v2] cfq: High precision slice tuning Jan Kara
@ 2016-06-08 13:11 ` Jan Kara
2016-06-08 13:11 ` [PATCH 2/3] cfq-iosched: Expose microsecond interfaces Jan Kara
` (2 subsequent siblings)
3 siblings, 0 replies; 5+ messages in thread
From: Jan Kara @ 2016-06-08 13:11 UTC (permalink / raw)
To: Jens Axboe; +Cc: linux-block, Jeff Moyer, Jan Kara
From: Jeff Moyer <jmoyer@redhat.com>
Convert all time-keeping in CFQ IO scheduler from jiffies to nanoseconds
so that we can later make the intervals more fine-grained than jiffies.
One jiffie is several miliseconds and even for today's rotating disks
that is a noticeable amount of time and thus we leave disk unnecessarily
idle.
Signed-off-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Jan Kara <jack@suse.cz>
---
block/cfq-iosched.c | 273 ++++++++++++++++++++++++++--------------------------
1 file changed, 136 insertions(+), 137 deletions(-)
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 4a349787bc62..228ff138a66b 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -10,7 +10,7 @@
#include <linux/slab.h>
#include <linux/blkdev.h>
#include <linux/elevator.h>
-#include <linux/jiffies.h>
+#include <linux/ktime.h>
#include <linux/rbtree.h>
#include <linux/ioprio.h>
#include <linux/blktrace_api.h>
@@ -22,28 +22,28 @@
*/
/* max queue in one round of service */
static const int cfq_quantum = 8;
-static const int cfq_fifo_expire[2] = { HZ / 4, HZ / 8 };
+static const u64 cfq_fifo_expire[2] = { NSEC_PER_SEC / 4, NSEC_PER_SEC / 8 };
/* maximum backwards seek, in KiB */
static const int cfq_back_max = 16 * 1024;
/* penalty of a backwards seek */
static const int cfq_back_penalty = 2;
-static const int cfq_slice_sync = HZ / 10;
-static int cfq_slice_async = HZ / 25;
+static const u64 cfq_slice_sync = NSEC_PER_SEC / 10;
+static u64 cfq_slice_async = NSEC_PER_SEC / 25;
static const int cfq_slice_async_rq = 2;
-static int cfq_slice_idle = HZ / 125;
-static int cfq_group_idle = HZ / 125;
-static const int cfq_target_latency = HZ * 3/10; /* 300 ms */
+static u64 cfq_slice_idle = NSEC_PER_SEC / 125;
+static u64 cfq_group_idle = NSEC_PER_SEC / 125;
+static const u64 cfq_target_latency = (u64)NSEC_PER_SEC * 3/10; /* 300 ms */
static const int cfq_hist_divisor = 4;
/*
* offset from end of service tree
*/
-#define CFQ_IDLE_DELAY (HZ / 5)
+#define CFQ_IDLE_DELAY (NSEC_PER_SEC / 5)
/*
* below this threshold, we consider thinktime immediate
*/
-#define CFQ_MIN_TT (2)
+#define CFQ_MIN_TT (2 * NSEC_PER_SEC / HZ)
#define CFQ_SLICE_SCALE (5)
#define CFQ_HW_QUEUE_MIN (5)
@@ -73,11 +73,11 @@ static struct kmem_cache *cfq_pool;
#define CFQ_WEIGHT_LEGACY_MAX 1000
struct cfq_ttime {
- unsigned long last_end_request;
+ u64 last_end_request;
- unsigned long ttime_total;
+ u64 ttime_total;
+ u64 ttime_mean;
unsigned long ttime_samples;
- unsigned long ttime_mean;
};
/*
@@ -94,7 +94,7 @@ struct cfq_rb_root {
struct cfq_ttime ttime;
};
#define CFQ_RB_ROOT (struct cfq_rb_root) { .rb = RB_ROOT, \
- .ttime = {.last_end_request = jiffies,},}
+ .ttime = {.last_end_request = ktime_get_ns(),},}
/*
* Per process-grouping structure
@@ -109,7 +109,7 @@ struct cfq_queue {
/* service_tree member */
struct rb_node rb_node;
/* service_tree key */
- unsigned long rb_key;
+ u64 rb_key;
/* prio tree member */
struct rb_node p_node;
/* prio tree root we belong to, if any */
@@ -126,13 +126,13 @@ struct cfq_queue {
struct list_head fifo;
/* time when queue got scheduled in to dispatch first request. */
- unsigned long dispatch_start;
- unsigned int allocated_slice;
- unsigned int slice_dispatch;
+ u64 dispatch_start;
+ u64 allocated_slice;
+ u64 slice_dispatch;
/* time when first request from queue completed and slice started. */
- unsigned long slice_start;
- unsigned long slice_end;
- long slice_resid;
+ u64 slice_start;
+ u64 slice_end;
+ u64 slice_resid;
/* pending priority requests */
int prio_pending;
@@ -290,7 +290,7 @@ struct cfq_group {
struct cfq_rb_root service_trees[2][3];
struct cfq_rb_root service_tree_idle;
- unsigned long saved_wl_slice;
+ u64 saved_wl_slice;
enum wl_type_t saved_wl_type;
enum wl_class_t saved_wl_class;
@@ -329,7 +329,7 @@ struct cfq_data {
*/
enum wl_class_t serving_wl_class;
enum wl_type_t serving_wl_type;
- unsigned long workload_expires;
+ u64 workload_expires;
struct cfq_group *serving_group;
/*
@@ -374,22 +374,22 @@ struct cfq_data {
* tunables, see top of file
*/
unsigned int cfq_quantum;
- unsigned int cfq_fifo_expire[2];
unsigned int cfq_back_penalty;
unsigned int cfq_back_max;
- unsigned int cfq_slice[2];
unsigned int cfq_slice_async_rq;
- unsigned int cfq_slice_idle;
- unsigned int cfq_group_idle;
unsigned int cfq_latency;
- unsigned int cfq_target_latency;
+ u64 cfq_fifo_expire[2];
+ u64 cfq_slice[2];
+ u64 cfq_slice_idle;
+ u64 cfq_group_idle;
+ u64 cfq_target_latency;
/*
* Fallback dummy cfqq for extreme OOM conditions
*/
struct cfq_queue oom_cfqq;
- unsigned long last_delayed_sync;
+ u64 last_delayed_sync;
};
static struct cfq_group *cfq_get_next_cfqg(struct cfq_data *cfqd);
@@ -675,7 +675,7 @@ static inline void cfqg_stats_update_io_add(struct cfq_group *cfqg,
}
static inline void cfqg_stats_update_timeslice_used(struct cfq_group *cfqg,
- unsigned long time, unsigned long unaccounted_time)
+ uint64_t time, uint64_t unaccounted_time)
{
blkg_stat_add(&cfqg->stats.time, time);
#ifdef CONFIG_DEBUG_BLK_CGROUP
@@ -783,7 +783,7 @@ static inline void cfqg_put(struct cfq_group *cfqg) { }
static inline void cfqg_stats_update_io_add(struct cfq_group *cfqg,
struct cfq_group *curr_cfqg, int rw) { }
static inline void cfqg_stats_update_timeslice_used(struct cfq_group *cfqg,
- unsigned long time, unsigned long unaccounted_time) { }
+ uint64_t time, uint64_t unaccounted_time) { }
static inline void cfqg_stats_update_io_remove(struct cfq_group *cfqg, int rw) { }
static inline void cfqg_stats_update_io_merged(struct cfq_group *cfqg, int rw) { }
static inline void cfqg_stats_update_completion(struct cfq_group *cfqg,
@@ -807,7 +807,7 @@ static inline void cfqg_stats_update_completion(struct cfq_group *cfqg,
static inline bool cfq_io_thinktime_big(struct cfq_data *cfqd,
struct cfq_ttime *ttime, bool group_idle)
{
- unsigned long slice;
+ u64 slice;
if (!sample_valid(ttime->ttime_samples))
return false;
if (group_idle)
@@ -930,17 +930,18 @@ static inline void cfq_schedule_dispatch(struct cfq_data *cfqd)
* if a queue is marked sync and has sync io queued. A sync queue with async
* io only, should not get full sync slice length.
*/
-static inline int cfq_prio_slice(struct cfq_data *cfqd, bool sync,
+static inline u64 cfq_prio_slice(struct cfq_data *cfqd, bool sync,
unsigned short prio)
{
- const int base_slice = cfqd->cfq_slice[sync];
+ u64 base_slice = cfqd->cfq_slice[sync];
+ u64 slice = div_u64(base_slice, CFQ_SLICE_SCALE);
WARN_ON(prio >= IOPRIO_BE_NR);
- return base_slice + (base_slice/CFQ_SLICE_SCALE * (4 - prio));
+ return base_slice + (slice * (4 - prio));
}
-static inline int
+static inline u64
cfq_prio_to_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq)
{
return cfq_prio_slice(cfqd, cfq_cfqq_sync(cfqq), cfqq->ioprio);
@@ -958,15 +959,14 @@ cfq_prio_to_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq)
*
* The result is also in fixed point w/ CFQ_SERVICE_SHIFT.
*/
-static inline u64 cfqg_scale_charge(unsigned long charge,
+static inline u64 cfqg_scale_charge(u64 charge,
unsigned int vfraction)
{
u64 c = charge << CFQ_SERVICE_SHIFT; /* make it fixed point */
/* charge / vfraction */
c <<= CFQ_SERVICE_SHIFT;
- do_div(c, vfraction);
- return c;
+ return div_u64(c, vfraction);
}
static inline u64 max_vdisktime(u64 min_vdisktime, u64 vdisktime)
@@ -1019,16 +1019,16 @@ static inline unsigned cfq_group_get_avg_queues(struct cfq_data *cfqd,
return cfqg->busy_queues_avg[rt];
}
-static inline unsigned
+static inline u64
cfq_group_slice(struct cfq_data *cfqd, struct cfq_group *cfqg)
{
return cfqd->cfq_target_latency * cfqg->vfraction >> CFQ_SERVICE_SHIFT;
}
-static inline unsigned
+static inline u64
cfq_scaled_cfqq_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq)
{
- unsigned slice = cfq_prio_to_slice(cfqd, cfqq);
+ u64 slice = cfq_prio_to_slice(cfqd, cfqq);
if (cfqd->cfq_latency) {
/*
* interested queues (we consider only the ones with the same
@@ -1036,20 +1036,22 @@ cfq_scaled_cfqq_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq)
*/
unsigned iq = cfq_group_get_avg_queues(cfqd, cfqq->cfqg,
cfq_class_rt(cfqq));
- unsigned sync_slice = cfqd->cfq_slice[1];
- unsigned expect_latency = sync_slice * iq;
- unsigned group_slice = cfq_group_slice(cfqd, cfqq->cfqg);
+ u64 sync_slice = cfqd->cfq_slice[1];
+ u64 expect_latency = sync_slice * iq;
+ u64 group_slice = cfq_group_slice(cfqd, cfqq->cfqg);
if (expect_latency > group_slice) {
- unsigned base_low_slice = 2 * cfqd->cfq_slice_idle;
+ u64 base_low_slice = 2 * cfqd->cfq_slice_idle;
+ u64 low_slice;
+
/* scale low_slice according to IO priority
* and sync vs async */
- unsigned low_slice =
- min(slice, base_low_slice * slice / sync_slice);
+ low_slice = div64_u64(base_low_slice*slice, sync_slice);
+ low_slice = min(slice, low_slice);
/* the adapted slice value is scaled to fit all iqs
* into the target latency */
- slice = max(slice * group_slice / expect_latency,
- low_slice);
+ slice = div64_u64(slice*group_slice, expect_latency);
+ slice = max(slice, low_slice);
}
}
return slice;
@@ -1058,12 +1060,13 @@ cfq_scaled_cfqq_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq)
static inline void
cfq_set_prio_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq)
{
- unsigned slice = cfq_scaled_cfqq_slice(cfqd, cfqq);
+ u64 slice = cfq_scaled_cfqq_slice(cfqd, cfqq);
+ u64 now = ktime_get_ns();
- cfqq->slice_start = jiffies;
- cfqq->slice_end = jiffies + slice;
+ cfqq->slice_start = now;
+ cfqq->slice_end = now + slice;
cfqq->allocated_slice = slice;
- cfq_log_cfqq(cfqd, cfqq, "set_slice=%lu", cfqq->slice_end - jiffies);
+ cfq_log_cfqq(cfqd, cfqq, "set_slice=%llu", cfqq->slice_end - now);
}
/*
@@ -1075,7 +1078,7 @@ static inline bool cfq_slice_used(struct cfq_queue *cfqq)
{
if (cfq_cfqq_slice_new(cfqq))
return false;
- if (time_before(jiffies, cfqq->slice_end))
+ if (ktime_get_ns() < cfqq->slice_end)
return false;
return true;
@@ -1241,8 +1244,8 @@ cfq_find_next_rq(struct cfq_data *cfqd, struct cfq_queue *cfqq,
return cfq_choose_req(cfqd, next, prev, blk_rq_pos(last));
}
-static unsigned long cfq_slice_offset(struct cfq_data *cfqd,
- struct cfq_queue *cfqq)
+static u64 cfq_slice_offset(struct cfq_data *cfqd,
+ struct cfq_queue *cfqq)
{
/*
* just an approximation, should be ok.
@@ -1435,31 +1438,31 @@ cfq_group_notify_queue_del(struct cfq_data *cfqd, struct cfq_group *cfqg)
cfqg_stats_update_dequeue(cfqg);
}
-static inline unsigned int cfq_cfqq_slice_usage(struct cfq_queue *cfqq,
- unsigned int *unaccounted_time)
+static inline u64 cfq_cfqq_slice_usage(struct cfq_queue *cfqq,
+ u64 *unaccounted_time)
{
- unsigned int slice_used;
+ u64 slice_used;
+ u64 now = ktime_get_ns();
/*
* Queue got expired before even a single request completed or
* got expired immediately after first request completion.
*/
- if (!cfqq->slice_start || cfqq->slice_start == jiffies) {
+ if (!cfqq->slice_start || cfqq->slice_start == now) {
/*
* Also charge the seek time incurred to the group, otherwise
* if there are mutiple queues in the group, each can dispatch
* a single request on seeky media and cause lots of seek time
* and group will never know it.
*/
- slice_used = max_t(unsigned, (jiffies - cfqq->dispatch_start),
- 1);
+ slice_used = max_t(u64, (now - cfqq->dispatch_start), 1);
} else {
- slice_used = jiffies - cfqq->slice_start;
+ slice_used = now - cfqq->slice_start;
if (slice_used > cfqq->allocated_slice) {
*unaccounted_time = slice_used - cfqq->allocated_slice;
slice_used = cfqq->allocated_slice;
}
- if (time_after(cfqq->slice_start, cfqq->dispatch_start))
+ if (cfqq->slice_start > cfqq->dispatch_start)
*unaccounted_time += cfqq->slice_start -
cfqq->dispatch_start;
}
@@ -1471,10 +1474,11 @@ static void cfq_group_served(struct cfq_data *cfqd, struct cfq_group *cfqg,
struct cfq_queue *cfqq)
{
struct cfq_rb_root *st = &cfqd->grp_service_tree;
- unsigned int used_sl, charge, unaccounted_sl = 0;
+ u64 used_sl, charge, unaccounted_sl = 0;
int nr_sync = cfqg->nr_cfqq - cfqg_busy_async_queues(cfqd, cfqg)
- cfqg->service_tree_idle.count;
unsigned int vfr;
+ u64 now = ktime_get_ns();
BUG_ON(nr_sync < 0);
used_sl = charge = cfq_cfqq_slice_usage(cfqq, &unaccounted_sl);
@@ -1496,9 +1500,8 @@ static void cfq_group_served(struct cfq_data *cfqd, struct cfq_group *cfqg,
cfq_group_service_tree_add(st, cfqg);
/* This group is being expired. Save the context */
- if (time_after(cfqd->workload_expires, jiffies)) {
- cfqg->saved_wl_slice = cfqd->workload_expires
- - jiffies;
+ if (cfqd->workload_expires > now) {
+ cfqg->saved_wl_slice = cfqd->workload_expires - now;
cfqg->saved_wl_type = cfqd->serving_wl_type;
cfqg->saved_wl_class = cfqd->serving_wl_class;
} else
@@ -1507,7 +1510,7 @@ static void cfq_group_served(struct cfq_data *cfqd, struct cfq_group *cfqg,
cfq_log_cfqg(cfqd, cfqg, "served: vt=%llu min_vt=%llu", cfqg->vdisktime,
st->min_vdisktime);
cfq_log_cfqq(cfqq->cfqd, cfqq,
- "sl_used=%u disp=%u charge=%u iops=%u sect=%lu",
+ "sl_used=%llu disp=%llu charge=%llu iops=%u sect=%lu",
used_sl, cfqq->slice_dispatch, charge,
iops_mode(cfqd), cfqq->nr_sectors);
cfqg_stats_update_timeslice_used(cfqg, used_sl, unaccounted_sl);
@@ -1530,7 +1533,7 @@ static void cfq_init_cfqg_base(struct cfq_group *cfqg)
*st = CFQ_RB_ROOT;
RB_CLEAR_NODE(&cfqg->rb_node);
- cfqg->ttime.last_end_request = jiffies;
+ cfqg->ttime.last_end_request = ktime_get_ns();
}
#ifdef CONFIG_CFQ_GROUP_IOSCHED
@@ -2213,10 +2216,11 @@ static void cfq_service_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq,
{
struct rb_node **p, *parent;
struct cfq_queue *__cfqq;
- unsigned long rb_key;
+ u64 rb_key;
struct cfq_rb_root *st;
int left;
int new_cfqq = 1;
+ u64 now = ktime_get_ns();
st = st_for(cfqq->cfqg, cfqq_class(cfqq), cfqq_type(cfqq));
if (cfq_class_idle(cfqq)) {
@@ -2226,7 +2230,7 @@ static void cfq_service_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq,
__cfqq = rb_entry(parent, struct cfq_queue, rb_node);
rb_key += __cfqq->rb_key;
} else
- rb_key += jiffies;
+ rb_key += now;
} else if (!add_front) {
/*
* Get our rb key offset. Subtract any residual slice
@@ -2234,13 +2238,13 @@ static void cfq_service_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq,
* count indicates slice overrun, and this should position
* the next service time further away in the tree.
*/
- rb_key = cfq_slice_offset(cfqd, cfqq) + jiffies;
+ rb_key = cfq_slice_offset(cfqd, cfqq) + now;
rb_key -= cfqq->slice_resid;
cfqq->slice_resid = 0;
} else {
- rb_key = -HZ;
+ rb_key = -NSEC_PER_SEC;
__cfqq = cfq_rb_first(st);
- rb_key += __cfqq ? __cfqq->rb_key : jiffies;
+ rb_key += __cfqq ? __cfqq->rb_key : now;
}
if (!RB_EMPTY_NODE(&cfqq->rb_node)) {
@@ -2266,7 +2270,7 @@ static void cfq_service_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq,
/*
* sort by key, that represents service time.
*/
- if (time_before(rb_key, __cfqq->rb_key))
+ if (rb_key < __cfqq->rb_key)
p = &parent->rb_left;
else {
p = &parent->rb_right;
@@ -2566,7 +2570,7 @@ cfq_merged_requests(struct request_queue *q, struct request *rq,
* reposition in fifo if next is older than rq
*/
if (!list_empty(&rq->queuelist) && !list_empty(&next->queuelist) &&
- time_before(next->fifo_time, rq->fifo_time) &&
+ next->fifo_time < rq->fifo_time &&
cfqq == RQ_CFQQ(next)) {
list_move(&rq->queuelist, &next->queuelist);
rq->fifo_time = next->fifo_time;
@@ -2627,7 +2631,7 @@ static void __cfq_set_active_queue(struct cfq_data *cfqd,
cfqd->serving_wl_class, cfqd->serving_wl_type);
cfqg_stats_update_avg_queue_size(cfqq->cfqg);
cfqq->slice_start = 0;
- cfqq->dispatch_start = jiffies;
+ cfqq->dispatch_start = ktime_get_ns();
cfqq->allocated_slice = 0;
cfqq->slice_end = 0;
cfqq->slice_dispatch = 0;
@@ -2676,8 +2680,8 @@ __cfq_slice_expired(struct cfq_data *cfqd, struct cfq_queue *cfqq,
if (cfq_cfqq_slice_new(cfqq))
cfqq->slice_resid = cfq_scaled_cfqq_slice(cfqd, cfqq);
else
- cfqq->slice_resid = cfqq->slice_end - jiffies;
- cfq_log_cfqq(cfqd, cfqq, "resid=%ld", cfqq->slice_resid);
+ cfqq->slice_resid = cfqq->slice_end - ktime_get_ns();
+ cfq_log_cfqq(cfqd, cfqq, "resid=%llu", cfqq->slice_resid);
}
cfq_group_served(cfqd, cfqq->cfqg, cfqq);
@@ -2911,7 +2915,8 @@ static void cfq_arm_slice_timer(struct cfq_data *cfqd)
struct cfq_queue *cfqq = cfqd->active_queue;
struct cfq_rb_root *st = cfqq->service_tree;
struct cfq_io_cq *cic;
- unsigned long sl, group_idle = 0;
+ u64 sl, group_idle = 0;
+ u64 now = ktime_get_ns();
/*
* SSD device without seek penalty, disable idling. But only do so
@@ -2954,8 +2959,8 @@ static void cfq_arm_slice_timer(struct cfq_data *cfqd)
* time slice.
*/
if (sample_valid(cic->ttime.ttime_samples) &&
- (cfqq->slice_end - jiffies < cic->ttime.ttime_mean)) {
- cfq_log_cfqq(cfqd, cfqq, "Not idling. think_time:%lu",
+ (cfqq->slice_end - now < cic->ttime.ttime_mean)) {
+ cfq_log_cfqq(cfqd, cfqq, "Not idling. think_time:%llu",
cic->ttime.ttime_mean);
return;
}
@@ -2976,9 +2981,9 @@ static void cfq_arm_slice_timer(struct cfq_data *cfqd)
else
sl = cfqd->cfq_slice_idle;
- mod_timer(&cfqd->idle_slice_timer, jiffies + sl);
+ mod_timer(&cfqd->idle_slice_timer, now + sl);
cfqg_stats_set_start_idle_time(cfqq->cfqg);
- cfq_log_cfqq(cfqd, cfqq, "arm_idle: %lu group_idle: %d", sl,
+ cfq_log_cfqq(cfqd, cfqq, "arm_idle: %llu group_idle: %d", sl,
group_idle ? 1 : 0);
}
@@ -3018,7 +3023,7 @@ static struct request *cfq_check_fifo(struct cfq_queue *cfqq)
return NULL;
rq = rq_entry_fifo(cfqq->fifo.next);
- if (time_before(jiffies, rq->fifo_time))
+ if (ktime_get_ns() < rq->fifo_time)
rq = NULL;
cfq_log_cfqq(cfqq->cfqd, cfqq, "fifo=%p", rq);
@@ -3096,14 +3101,14 @@ static enum wl_type_t cfq_choose_wl_type(struct cfq_data *cfqd,
struct cfq_queue *queue;
int i;
bool key_valid = false;
- unsigned long lowest_key = 0;
+ u64 lowest_key = 0;
enum wl_type_t cur_best = SYNC_NOIDLE_WORKLOAD;
for (i = 0; i <= SYNC_WORKLOAD; ++i) {
/* select the one with lowest rb_key */
queue = cfq_rb_first(st_for(cfqg, wl_class, i));
if (queue &&
- (!key_valid || time_before(queue->rb_key, lowest_key))) {
+ (!key_valid || queue->rb_key < lowest_key)) {
lowest_key = queue->rb_key;
cur_best = i;
key_valid = true;
@@ -3116,11 +3121,12 @@ static enum wl_type_t cfq_choose_wl_type(struct cfq_data *cfqd,
static void
choose_wl_class_and_type(struct cfq_data *cfqd, struct cfq_group *cfqg)
{
- unsigned slice;
+ u64 slice;
unsigned count;
struct cfq_rb_root *st;
- unsigned group_slice;
+ u64 group_slice;
enum wl_class_t original_class = cfqd->serving_wl_class;
+ u64 now = ktime_get_ns();
/* Choose next priority. RT > BE > IDLE */
if (cfq_group_busy_queues_wl(RT_WORKLOAD, cfqd, cfqg))
@@ -3129,7 +3135,7 @@ choose_wl_class_and_type(struct cfq_data *cfqd, struct cfq_group *cfqg)
cfqd->serving_wl_class = BE_WORKLOAD;
else {
cfqd->serving_wl_class = IDLE_WORKLOAD;
- cfqd->workload_expires = jiffies + 1;
+ cfqd->workload_expires = now + jiffies_to_nsecs(1);
return;
}
@@ -3147,7 +3153,7 @@ choose_wl_class_and_type(struct cfq_data *cfqd, struct cfq_group *cfqg)
/*
* check workload expiration, and that we still have other queues ready
*/
- if (count && !time_after(jiffies, cfqd->workload_expires))
+ if (count && !(now > cfqd->workload_expires))
return;
new_workload:
@@ -3164,13 +3170,13 @@ new_workload:
*/
group_slice = cfq_group_slice(cfqd, cfqg);
- slice = group_slice * count /
+ slice = div_u64(group_slice * count,
max_t(unsigned, cfqg->busy_queues_avg[cfqd->serving_wl_class],
cfq_group_busy_queues_wl(cfqd->serving_wl_class, cfqd,
- cfqg));
+ cfqg)));
if (cfqd->serving_wl_type == ASYNC_WORKLOAD) {
- unsigned int tmp;
+ u64 tmp;
/*
* Async queues are currently system wide. Just taking
@@ -3181,19 +3187,19 @@ new_workload:
*/
tmp = cfqd->cfq_target_latency *
cfqg_busy_async_queues(cfqd, cfqg);
- tmp = tmp/cfqd->busy_queues;
- slice = min_t(unsigned, slice, tmp);
+ tmp = div_u64(tmp, cfqd->busy_queues);
+ slice = min_t(u64, slice, tmp);
/* async workload slice is scaled down according to
* the sync/async slice ratio. */
- slice = slice * cfqd->cfq_slice[0] / cfqd->cfq_slice[1];
+ slice = div64_u64(slice*cfqd->cfq_slice[0], cfqd->cfq_slice[1]);
} else
/* sync workload slice is at least 2 * cfq_slice_idle */
slice = max(slice, 2 * cfqd->cfq_slice_idle);
- slice = max_t(unsigned, slice, CFQ_MIN_TT);
- cfq_log(cfqd, "workload slice:%d", slice);
- cfqd->workload_expires = jiffies + slice;
+ slice = max_t(u64, slice, CFQ_MIN_TT);
+ cfq_log(cfqd, "workload slice:%llu", slice);
+ cfqd->workload_expires = now + slice;
}
static struct cfq_group *cfq_get_next_cfqg(struct cfq_data *cfqd)
@@ -3211,16 +3217,17 @@ static struct cfq_group *cfq_get_next_cfqg(struct cfq_data *cfqd)
static void cfq_choose_cfqg(struct cfq_data *cfqd)
{
struct cfq_group *cfqg = cfq_get_next_cfqg(cfqd);
+ u64 now = ktime_get_ns();
cfqd->serving_group = cfqg;
/* Restore the workload type data */
if (cfqg->saved_wl_slice) {
- cfqd->workload_expires = jiffies + cfqg->saved_wl_slice;
+ cfqd->workload_expires = now + cfqg->saved_wl_slice;
cfqd->serving_wl_type = cfqg->saved_wl_type;
cfqd->serving_wl_class = cfqg->saved_wl_class;
} else
- cfqd->workload_expires = jiffies - 1;
+ cfqd->workload_expires = now - 1;
choose_wl_class_and_type(cfqd, cfqg);
}
@@ -3232,6 +3239,7 @@ static void cfq_choose_cfqg(struct cfq_data *cfqd)
static struct cfq_queue *cfq_select_queue(struct cfq_data *cfqd)
{
struct cfq_queue *cfqq, *new_cfqq = NULL;
+ u64 now = ktime_get_ns();
cfqq = cfqd->active_queue;
if (!cfqq)
@@ -3303,7 +3311,7 @@ static struct cfq_queue *cfq_select_queue(struct cfq_data *cfqd)
**/
if (CFQQ_SEEKY(cfqq) && cfq_cfqq_idle_window(cfqq) &&
(cfq_cfqq_slice_new(cfqq) ||
- (cfqq->slice_end - jiffies > jiffies - cfqq->slice_start))) {
+ (cfqq->slice_end - now > now - cfqq->slice_start))) {
cfq_clear_cfqq_deep(cfqq);
cfq_clear_cfqq_idle_window(cfqq);
}
@@ -3381,11 +3389,12 @@ static int cfq_forced_dispatch(struct cfq_data *cfqd)
static inline bool cfq_slice_used_soon(struct cfq_data *cfqd,
struct cfq_queue *cfqq)
{
+ u64 now = ktime_get_ns();
+
/* the queue hasn't finished any request, can't estimate */
if (cfq_cfqq_slice_new(cfqq))
return true;
- if (time_after(jiffies + cfqd->cfq_slice_idle * cfqq->dispatched,
- cfqq->slice_end))
+ if (now + cfqd->cfq_slice_idle * cfqq->dispatched > cfqq->slice_end)
return true;
return false;
@@ -3460,10 +3469,10 @@ static bool cfq_may_dispatch(struct cfq_data *cfqd, struct cfq_queue *cfqq)
* based on the last sync IO we serviced
*/
if (!cfq_cfqq_sync(cfqq) && cfqd->cfq_latency) {
- unsigned long last_sync = jiffies - cfqd->last_delayed_sync;
+ u64 last_sync = ktime_get_ns() - cfqd->last_delayed_sync;
unsigned int depth;
- depth = last_sync / cfqd->cfq_slice[1];
+ depth = div64_u64(last_sync, cfqd->cfq_slice[1]);
if (!depth && !cfqq->dispatched)
depth = 1;
if (depth < max_dispatch)
@@ -3546,7 +3555,7 @@ static int cfq_dispatch_requests(struct request_queue *q, int force)
if (cfqd->busy_queues > 1 && ((!cfq_cfqq_sync(cfqq) &&
cfqq->slice_dispatch >= cfq_prio_to_maxrq(cfqd, cfqq)) ||
cfq_class_idle(cfqq))) {
- cfqq->slice_end = jiffies + 1;
+ cfqq->slice_end = ktime_get_ns() + 1;
cfq_slice_expired(cfqd, 0);
}
@@ -3624,7 +3633,7 @@ static void cfq_init_icq(struct io_cq *icq)
{
struct cfq_io_cq *cic = icq_to_cic(icq);
- cic->ttime.last_end_request = jiffies;
+ cic->ttime.last_end_request = ktime_get_ns();
}
static void cfq_exit_icq(struct io_cq *icq)
@@ -3845,14 +3854,15 @@ out:
}
static void
-__cfq_update_io_thinktime(struct cfq_ttime *ttime, unsigned long slice_idle)
+__cfq_update_io_thinktime(struct cfq_ttime *ttime, u64 slice_idle)
{
- unsigned long elapsed = jiffies - ttime->last_end_request;
+ u64 elapsed = ktime_get_ns() - ttime->last_end_request;
elapsed = min(elapsed, 2UL * slice_idle);
ttime->ttime_samples = (7*ttime->ttime_samples + 256) / 8;
- ttime->ttime_total = (7*ttime->ttime_total + 256*elapsed) / 8;
- ttime->ttime_mean = (ttime->ttime_total + 128) / ttime->ttime_samples;
+ ttime->ttime_total = div_u64(7*ttime->ttime_total + 256*elapsed, 8);
+ ttime->ttime_mean = div64_ul(ttime->ttime_total + 128,
+ ttime->ttime_samples);
}
static void
@@ -4105,7 +4115,7 @@ static void cfq_insert_request(struct request_queue *q, struct request *rq)
cfq_log_cfqq(cfqd, cfqq, "insert_request");
cfq_init_prio_data(cfqq, RQ_CIC(rq));
- rq->fifo_time = jiffies + cfqd->cfq_fifo_expire[rq_is_sync(rq)];
+ rq->fifo_time = ktime_get_ns() + cfqd->cfq_fifo_expire[rq_is_sync(rq)];
list_add_tail(&rq->queuelist, &cfqq->fifo);
cfq_add_rq_rb(rq);
cfqg_stats_update_io_add(RQ_CFQG(rq), cfqd->serving_group,
@@ -4153,6 +4163,7 @@ static void cfq_update_hw_tag(struct cfq_data *cfqd)
static bool cfq_should_wait_busy(struct cfq_data *cfqd, struct cfq_queue *cfqq)
{
struct cfq_io_cq *cic = cfqd->active_cic;
+ u64 now = ktime_get_ns();
/* If the queue already has requests, don't wait */
if (!RB_EMPTY_ROOT(&cfqq->sort_list))
@@ -4171,7 +4182,7 @@ static bool cfq_should_wait_busy(struct cfq_data *cfqd, struct cfq_queue *cfqq)
/* if slice left is less than think time, wait busy */
if (cic && sample_valid(cic->ttime.ttime_samples)
- && (cfqq->slice_end - jiffies < cic->ttime.ttime_mean))
+ && (cfqq->slice_end - now < cic->ttime.ttime_mean))
return true;
/*
@@ -4181,7 +4192,7 @@ static bool cfq_should_wait_busy(struct cfq_data *cfqd, struct cfq_queue *cfqq)
* case where think time is less than a jiffy, mark the queue wait
* busy if only 1 jiffy is left in the slice.
*/
- if (cfqq->slice_end - jiffies == 1)
+ if (cfqq->slice_end - now <= jiffies_to_nsecs(1))
return true;
return false;
@@ -4192,9 +4203,8 @@ static void cfq_completed_request(struct request_queue *q, struct request *rq)
struct cfq_queue *cfqq = RQ_CFQQ(rq);
struct cfq_data *cfqd = cfqq->cfqd;
const int sync = rq_is_sync(rq);
- unsigned long now;
+ u64 now = ktime_get_ns();
- now = jiffies;
cfq_log_cfqq(cfqd, cfqq, "complete rqnoidle %d",
!!(rq->cmd_flags & REQ_NOIDLE));
@@ -4222,7 +4232,7 @@ static void cfq_completed_request(struct request_queue *q, struct request *rq)
cfqq_type(cfqq));
st->ttime.last_end_request = now;
- if (!time_after(rq->start_time + cfqd->cfq_fifo_expire[1], now))
+ if (!(rq->start_time + cfqd->cfq_fifo_expire[1] > now))
cfqd->last_delayed_sync = now;
}
@@ -4247,10 +4257,10 @@ static void cfq_completed_request(struct request_queue *q, struct request *rq)
* the queue.
*/
if (cfq_should_wait_busy(cfqd, cfqq)) {
- unsigned long extend_sl = cfqd->cfq_slice_idle;
+ u64 extend_sl = cfqd->cfq_slice_idle;
if (!cfqd->cfq_slice_idle)
extend_sl = cfqd->cfq_group_idle;
- cfqq->slice_end = jiffies + extend_sl;
+ cfqq->slice_end = now + extend_sl;
cfq_mark_cfqq_wait_busy(cfqq);
cfq_log_cfqq(cfqd, cfqq, "will busy wait");
}
@@ -4609,7 +4619,7 @@ static int cfq_init_queue(struct request_queue *q, struct elevator_type *e)
* we optimistically start assuming sync ops weren't delayed in last
* second, in order to have larger depth for async operations.
*/
- cfqd->last_delayed_sync = jiffies - HZ;
+ cfqd->last_delayed_sync = ktime_get_ns() - NSEC_PER_SEC;
return 0;
out_free:
@@ -4652,9 +4662,9 @@ cfq_var_store(unsigned int *var, const char *page, size_t count)
static ssize_t __FUNC(struct elevator_queue *e, char *page) \
{ \
struct cfq_data *cfqd = e->elevator_data; \
- unsigned int __data = __VAR; \
+ u64 __data = __VAR; \
if (__CONV) \
- __data = jiffies_to_msecs(__data); \
+ __data = div_u64(__data, NSEC_PER_MSEC); \
return cfq_var_show(__data, (page)); \
}
SHOW_FUNCTION(cfq_quantum_show, cfqd->cfq_quantum, 0);
@@ -4682,7 +4692,7 @@ static ssize_t __FUNC(struct elevator_queue *e, const char *page, size_t count)
else if (__data > (MAX)) \
__data = (MAX); \
if (__CONV) \
- *(__PTR) = msecs_to_jiffies(__data); \
+ *(__PTR) = (u64)__data * NSEC_PER_MSEC; \
else \
*(__PTR) = __data; \
return ret; \
@@ -4776,18 +4786,7 @@ static int __init cfq_init(void)
{
int ret;
- /*
- * could be 0 on HZ < 1000 setups
- */
- if (!cfq_slice_async)
- cfq_slice_async = 1;
- if (!cfq_slice_idle)
- cfq_slice_idle = 1;
-
#ifdef CONFIG_CFQ_GROUP_IOSCHED
- if (!cfq_group_idle)
- cfq_group_idle = 1;
-
ret = blkcg_policy_register(&blkcg_policy_cfq);
if (ret)
return ret;
--
2.6.6
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