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block: stop passing 'cpu' to all percpu stats methods
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All of part_stat_* and related methods are used with preempt disabled,
so there is no need to pass cpu around to allow of them.  Just call
smp_processor_id() as needed.

Suggested-by: Jens Axboe <[email protected]>
Signed-off-by: Mike Snitzer <[email protected]>
Signed-off-by: Jens Axboe <[email protected]>
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@snitm @axboe
snitm authored and axboe committed Dec 10, 2018
1 parent dbd3bbd commit 112f158
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Showing 7 changed files with 46 additions and 52 deletions.
16 changes: 9 additions & 7 deletions block/bio.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1668,11 +1668,12 @@ void generic_start_io_acct(struct request_queue *q, int op,
unsigned long sectors, struct hd_struct *part)
{
const int sgrp = op_stat_group(op);
int cpu = part_stat_lock();

part_round_stats(q, cpu, part);
part_stat_inc(cpu, part, ios[sgrp]);
part_stat_add(cpu, part, sectors[sgrp], sectors);
part_stat_lock();

part_round_stats(q, part);
part_stat_inc(part, ios[sgrp]);
part_stat_add(part, sectors[sgrp], sectors);
part_inc_in_flight(q, part, op_is_write(op));

part_stat_unlock();
Expand All @@ -1684,10 +1685,11 @@ void generic_end_io_acct(struct request_queue *q, int req_op,
{
unsigned long duration = jiffies - start_time;
const int sgrp = op_stat_group(req_op);
int cpu = part_stat_lock();

part_stat_add(cpu, part, nsecs[sgrp], jiffies_to_nsecs(duration));
part_round_stats(q, cpu, part);
part_stat_lock();

part_stat_add(part, nsecs[sgrp], jiffies_to_nsecs(duration));
part_round_stats(q, part);
part_dec_in_flight(q, part, op_is_write(req_op));

part_stat_unlock();
Expand Down
34 changes: 15 additions & 19 deletions block/blk-core.c
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Original file line number Diff line number Diff line change
Expand Up @@ -584,22 +584,21 @@ struct request *blk_get_request(struct request_queue *q, unsigned int op,
}
EXPORT_SYMBOL(blk_get_request);

static void part_round_stats_single(struct request_queue *q, int cpu,
static void part_round_stats_single(struct request_queue *q,
struct hd_struct *part, unsigned long now,
unsigned int inflight)
{
if (inflight) {
__part_stat_add(cpu, part, time_in_queue,
__part_stat_add(part, time_in_queue,
inflight * (now - part->stamp));
__part_stat_add(cpu, part, io_ticks, (now - part->stamp));
__part_stat_add(part, io_ticks, (now - part->stamp));
}
part->stamp = now;
}

/**
* part_round_stats() - Round off the performance stats on a struct disk_stats.
* @q: target block queue
* @cpu: cpu number for stats access
* @part: target partition
*
* The average IO queue length and utilisation statistics are maintained
Expand All @@ -613,7 +612,7 @@ static void part_round_stats_single(struct request_queue *q, int cpu,
* /proc/diskstats. This accounts immediately for all queue usage up to
* the current jiffies and restarts the counters again.
*/
void part_round_stats(struct request_queue *q, int cpu, struct hd_struct *part)
void part_round_stats(struct request_queue *q, struct hd_struct *part)
{
struct hd_struct *part2 = NULL;
unsigned long now = jiffies;
Expand All @@ -635,9 +634,9 @@ void part_round_stats(struct request_queue *q, int cpu, struct hd_struct *part)
part_in_flight(q, part, inflight);

if (stats & 2)
part_round_stats_single(q, cpu, part2, now, inflight[1]);
part_round_stats_single(q, part2, now, inflight[1]);
if (stats & 1)
part_round_stats_single(q, cpu, part, now, inflight[0]);
part_round_stats_single(q, part, now, inflight[0]);
}
EXPORT_SYMBOL_GPL(part_round_stats);

Expand Down Expand Up @@ -1362,11 +1361,10 @@ void blk_account_io_completion(struct request *req, unsigned int bytes)
if (blk_do_io_stat(req)) {
const int sgrp = op_stat_group(req_op(req));
struct hd_struct *part;
int cpu;

cpu = part_stat_lock();
part_stat_lock();
part = req->part;
part_stat_add(cpu, part, sectors[sgrp], bytes >> 9);
part_stat_add(part, sectors[sgrp], bytes >> 9);
part_stat_unlock();
}
}
Expand All @@ -1381,14 +1379,13 @@ void blk_account_io_done(struct request *req, u64 now)
if (blk_do_io_stat(req) && !(req->rq_flags & RQF_FLUSH_SEQ)) {
const int sgrp = op_stat_group(req_op(req));
struct hd_struct *part;
int cpu;

cpu = part_stat_lock();
part_stat_lock();
part = req->part;

part_stat_inc(cpu, part, ios[sgrp]);
part_stat_add(cpu, part, nsecs[sgrp], now - req->start_time_ns);
part_round_stats(req->q, cpu, part);
part_stat_inc(part, ios[sgrp]);
part_stat_add(part, nsecs[sgrp], now - req->start_time_ns);
part_round_stats(req->q, part);
part_dec_in_flight(req->q, part, rq_data_dir(req));

hd_struct_put(part);
Expand All @@ -1400,16 +1397,15 @@ void blk_account_io_start(struct request *rq, bool new_io)
{
struct hd_struct *part;
int rw = rq_data_dir(rq);
int cpu;

if (!blk_do_io_stat(rq))
return;

cpu = part_stat_lock();
part_stat_lock();

if (!new_io) {
part = rq->part;
part_stat_inc(cpu, part, merges[rw]);
part_stat_inc(part, merges[rw]);
} else {
part = disk_map_sector_rcu(rq->rq_disk, blk_rq_pos(rq));
if (!hd_struct_try_get(part)) {
Expand All @@ -1424,7 +1420,7 @@ void blk_account_io_start(struct request *rq, bool new_io)
part = &rq->rq_disk->part0;
hd_struct_get(part);
}
part_round_stats(rq->q, cpu, part);
part_round_stats(rq->q, part);
part_inc_in_flight(rq->q, part, rw);
rq->part = part;
}
Expand Down
5 changes: 2 additions & 3 deletions block/blk-merge.c
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Original file line number Diff line number Diff line change
Expand Up @@ -685,12 +685,11 @@ static void blk_account_io_merge(struct request *req)
{
if (blk_do_io_stat(req)) {
struct hd_struct *part;
int cpu;

cpu = part_stat_lock();
part_stat_lock();
part = req->part;

part_round_stats(req->q, cpu, part);
part_round_stats(req->q, part);
part_dec_in_flight(req->q, part, rq_data_dir(req));

hd_struct_put(part);
Expand Down
5 changes: 2 additions & 3 deletions block/genhd.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1326,7 +1326,6 @@ static int diskstats_show(struct seq_file *seqf, void *v)
struct hd_struct *hd;
char buf[BDEVNAME_SIZE];
unsigned int inflight[2];
int cpu;

/*
if (&disk_to_dev(gp)->kobj.entry == block_class.devices.next)
Expand All @@ -1338,8 +1337,8 @@ static int diskstats_show(struct seq_file *seqf, void *v)

disk_part_iter_init(&piter, gp, DISK_PITER_INCL_EMPTY_PART0);
while ((hd = disk_part_iter_next(&piter))) {
cpu = part_stat_lock();
part_round_stats(gp->queue, cpu, hd);
part_stat_lock();
part_round_stats(gp->queue, hd);
part_stat_unlock();
part_in_flight(gp->queue, hd, inflight);
seq_printf(seqf, "%4d %7d %s "
Expand Down
5 changes: 2 additions & 3 deletions block/partition-generic.c
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Original file line number Diff line number Diff line change
Expand Up @@ -121,10 +121,9 @@ ssize_t part_stat_show(struct device *dev,
struct hd_struct *p = dev_to_part(dev);
struct request_queue *q = part_to_disk(p)->queue;
unsigned int inflight[2];
int cpu;

cpu = part_stat_lock();
part_round_stats(q, cpu, p);
part_stat_lock();
part_round_stats(q, p);
part_stat_unlock();
part_in_flight(q, p, inflight);
return sprintf(buf,
Expand Down
7 changes: 3 additions & 4 deletions drivers/md/md.c
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Original file line number Diff line number Diff line change
Expand Up @@ -334,7 +334,6 @@ static blk_qc_t md_make_request(struct request_queue *q, struct bio *bio)
const int sgrp = op_stat_group(bio_op(bio));
struct mddev *mddev = q->queuedata;
unsigned int sectors;
int cpu;

blk_queue_split(q, &bio);

Expand All @@ -359,9 +358,9 @@ static blk_qc_t md_make_request(struct request_queue *q, struct bio *bio)

md_handle_request(mddev, bio);

cpu = part_stat_lock();
part_stat_inc(cpu, &mddev->gendisk->part0, ios[sgrp]);
part_stat_add(cpu, &mddev->gendisk->part0, sectors[sgrp], sectors);
part_stat_lock();
part_stat_inc(&mddev->gendisk->part0, ios[sgrp]);
part_stat_add(&mddev->gendisk->part0, sectors[sgrp], sectors);
part_stat_unlock();

return BLK_QC_T_NONE;
Expand Down
26 changes: 13 additions & 13 deletions include/linux/genhd.h
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Original file line number Diff line number Diff line change
Expand Up @@ -295,8 +295,8 @@ extern struct hd_struct *disk_map_sector_rcu(struct gendisk *disk,
#define part_stat_lock() ({ rcu_read_lock(); get_cpu(); })
#define part_stat_unlock() do { put_cpu(); rcu_read_unlock(); } while (0)

#define __part_stat_add(cpu, part, field, addnd) \
(per_cpu_ptr((part)->dkstats, (cpu))->field += (addnd))
#define __part_stat_add(part, field, addnd) \
(per_cpu_ptr((part)->dkstats, smp_processor_id())->field += (addnd))

#define part_stat_read(part, field) \
({ \
Expand Down Expand Up @@ -333,7 +333,7 @@ static inline void free_part_stats(struct hd_struct *part)
#define part_stat_lock() ({ rcu_read_lock(); 0; })
#define part_stat_unlock() rcu_read_unlock()

#define __part_stat_add(cpu, part, field, addnd) \
#define __part_stat_add(part, field, addnd) \
((part)->dkstats.field += addnd)

#define part_stat_read(part, field) ((part)->dkstats.field)
Expand Down Expand Up @@ -362,19 +362,19 @@ static inline void free_part_stats(struct hd_struct *part)
part_stat_read(part, field[STAT_WRITE]) + \
part_stat_read(part, field[STAT_DISCARD]))

#define part_stat_add(cpu, part, field, addnd) do { \
__part_stat_add((cpu), (part), field, addnd); \
#define part_stat_add(part, field, addnd) do { \
__part_stat_add((part), field, addnd); \
if ((part)->partno) \
__part_stat_add((cpu), &part_to_disk((part))->part0, \
__part_stat_add(&part_to_disk((part))->part0, \
field, addnd); \
} while (0)

#define part_stat_dec(cpu, gendiskp, field) \
part_stat_add(cpu, gendiskp, field, -1)
#define part_stat_inc(cpu, gendiskp, field) \
part_stat_add(cpu, gendiskp, field, 1)
#define part_stat_sub(cpu, gendiskp, field, subnd) \
part_stat_add(cpu, gendiskp, field, -subnd)
#define part_stat_dec(gendiskp, field) \
part_stat_add(gendiskp, field, -1)
#define part_stat_inc(gendiskp, field) \
part_stat_add(gendiskp, field, 1)
#define part_stat_sub(gendiskp, field, subnd) \
part_stat_add(gendiskp, field, -subnd)

void part_in_flight(struct request_queue *q, struct hd_struct *part,
unsigned int inflight[2]);
Expand All @@ -399,7 +399,7 @@ static inline void free_part_info(struct hd_struct *part)
}

/* block/blk-core.c */
extern void part_round_stats(struct request_queue *q, int cpu, struct hd_struct *part);
extern void part_round_stats(struct request_queue *q, struct hd_struct *part);

/* block/genhd.c */
extern void device_add_disk(struct device *parent, struct gendisk *disk,
Expand Down

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