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authorArtur Paszkiewicz <artur.paszkiewicz@intel.com>2020-07-03 11:13:09 +0200
committerSong Liu <songliubraving@fb.com>2020-07-13 23:06:56 -0700
commit41d2d848e5c09209bdb57ff9c0ca34075e22783d (patch)
treee4c114e4a7d2c0381cd30ebc8eaf5caa118ecbb4 /drivers/md/md.c
parent9a5a85972c073f720d81a7ebd08bfe278e6e16db (diff)
downloadlinux-41d2d848e5c09209bdb57ff9c0ca34075e22783d.tar.bz2
md: improve io stats accounting
Use generic io accounting functions to manage io stats. There was an attempt to do this earlier in commit 18c0b223cf99 ("md: use generic io stats accounting functions to simplify io stat accounting"), but it did not include a call to generic_end_io_acct() and caused issues with tracking in-flight IOs, so it was later removed in commit 74672d069b29 ("md: fix md io stats accounting broken"). This patch attempts to fix this by using both disk_start_io_acct() and disk_end_io_acct(). To make it possible, a struct md_io is allocated for every new md bio, which includes the io start_time. A new mempool is introduced for this purpose. We override bio->bi_end_io with our own callback and call disk_start_io_acct() before passing the bio to md_handle_request(). When it completes, we call disk_end_io_acct() and the original bi_end_io callback. This adds correct statistics about in-flight IOs and IO processing time, interpreted e.g. in iostat as await, svctm, aqu-sz and %util. It also fixes a situation where too many IOs where reported if a bio was re-submitted to the mddev, because io accounting is now performed only on newly arriving bios. Acked-by: Guoqing Jiang <guoqing.jiang@cloud.ionos.com> Signed-off-by: Artur Paszkiewicz <artur.paszkiewicz@intel.com> Signed-off-by: Song Liu <songliubraving@fb.com>
Diffstat (limited to 'drivers/md/md.c')
-rw-r--r--drivers/md/md.c57
1 files changed, 45 insertions, 12 deletions
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 49452149ac72..07e5b67a2c48 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -463,12 +463,33 @@ check_suspended:
}
EXPORT_SYMBOL(md_handle_request);
+struct md_io {
+ struct mddev *mddev;
+ bio_end_io_t *orig_bi_end_io;
+ void *orig_bi_private;
+ unsigned long start_time;
+};
+
+static void md_end_io(struct bio *bio)
+{
+ struct md_io *md_io = bio->bi_private;
+ struct mddev *mddev = md_io->mddev;
+
+ disk_end_io_acct(mddev->gendisk, bio_op(bio), md_io->start_time);
+
+ bio->bi_end_io = md_io->orig_bi_end_io;
+ bio->bi_private = md_io->orig_bi_private;
+
+ mempool_free(md_io, &mddev->md_io_pool);
+
+ if (bio->bi_end_io)
+ bio->bi_end_io(bio);
+}
+
static blk_qc_t md_submit_bio(struct bio *bio)
{
const int rw = bio_data_dir(bio);
- const int sgrp = op_stat_group(bio_op(bio));
struct mddev *mddev = bio->bi_disk->private_data;
- unsigned int sectors;
if (mddev == NULL || mddev->pers == NULL) {
bio_io_error(bio);
@@ -489,21 +510,27 @@ static blk_qc_t md_submit_bio(struct bio *bio)
return BLK_QC_T_NONE;
}
- /*
- * save the sectors now since our bio can
- * go away inside make_request
- */
- sectors = bio_sectors(bio);
+ if (bio->bi_end_io != md_end_io) {
+ struct md_io *md_io;
+
+ md_io = mempool_alloc(&mddev->md_io_pool, GFP_NOIO);
+ md_io->mddev = mddev;
+ md_io->orig_bi_end_io = bio->bi_end_io;
+ md_io->orig_bi_private = bio->bi_private;
+
+ bio->bi_end_io = md_end_io;
+ bio->bi_private = md_io;
+
+ md_io->start_time = disk_start_io_acct(mddev->gendisk,
+ bio_sectors(bio),
+ bio_op(bio));
+ }
+
/* bio could be mergeable after passing to underlayer */
bio->bi_opf &= ~REQ_NOMERGE;
md_handle_request(mddev, bio);
- 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;
}
@@ -5546,6 +5573,7 @@ static void md_free(struct kobject *ko)
bioset_exit(&mddev->bio_set);
bioset_exit(&mddev->sync_set);
+ mempool_exit(&mddev->md_io_pool);
kfree(mddev);
}
@@ -5641,6 +5669,11 @@ static int md_alloc(dev_t dev, char *name)
*/
mddev->hold_active = UNTIL_STOP;
+ error = mempool_init_kmalloc_pool(&mddev->md_io_pool, BIO_POOL_SIZE,
+ sizeof(struct md_io));
+ if (error)
+ goto abort;
+
error = -ENOMEM;
mddev->queue = blk_alloc_queue(NUMA_NO_NODE);
if (!mddev->queue)