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authorMing Lei <tom.leiming@gmail.com>2017-03-17 00:12:31 +0800
committerShaohua Li <shli@fb.com>2017-03-24 10:41:37 -0700
commit841c1316c7da6199a7df473893c141943991a756 (patch)
tree77bd223263ff1bc03d860f16b4ba4f60571e62b7 /drivers/md/raid1.c
parentd8c84c4f8becc1fb993911e18c8aef5ecf7a72ac (diff)
md: raid1: improve write behind
This patch improve handling of write behind in the following ways: - introduce behind master bio to hold all write behind pages - fast clone bios from behind master bio - avoid to change bvec table directly - use bio_copy_data() and make code more clean Suggested-by: Shaohua Li <shli@fb.com> Signed-off-by: Ming Lei <tom.leiming@gmail.com> Signed-off-by: Shaohua Li <shli@fb.com>
Diffstat (limited to 'drivers/md/raid1.c')
-rw-r--r--drivers/md/raid1.c118
1 files changed, 54 insertions, 64 deletions
diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index 64bf2005f082..c6a671f13bc0 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -388,12 +388,9 @@ static void close_write(struct r1bio *r1_bio)
{
/* it really is the end of this request */
if (test_bit(R1BIO_BehindIO, &r1_bio->state)) {
- /* free extra copy of the data pages */
- int i = r1_bio->behind_page_count;
- while (i--)
- safe_put_page(r1_bio->behind_bvecs[i].bv_page);
- kfree(r1_bio->behind_bvecs);
- r1_bio->behind_bvecs = NULL;
+ bio_free_pages(r1_bio->behind_master_bio);
+ bio_put(r1_bio->behind_master_bio);
+ r1_bio->behind_master_bio = NULL;
}
/* clear the bitmap if all writes complete successfully */
bitmap_endwrite(r1_bio->mddev->bitmap, r1_bio->sector,
@@ -495,6 +492,10 @@ static void raid1_end_write_request(struct bio *bio)
}
if (behind) {
+ /* we release behind master bio when all write are done */
+ if (r1_bio->behind_master_bio == bio)
+ to_put = NULL;
+
if (test_bit(WriteMostly, &rdev->flags))
atomic_dec(&r1_bio->behind_remaining);
@@ -1089,39 +1090,46 @@ static void unfreeze_array(struct r1conf *conf)
wake_up(&conf->wait_barrier);
}
-/* duplicate the data pages for behind I/O
- */
-static void alloc_behind_pages(struct bio *bio, struct r1bio *r1_bio)
+static struct bio *alloc_behind_master_bio(struct r1bio *r1_bio,
+ struct bio *bio,
+ int offset, int size)
{
- int i;
- struct bio_vec *bvec;
- struct bio_vec *bvecs = kzalloc(bio->bi_vcnt * sizeof(struct bio_vec),
- GFP_NOIO);
- if (unlikely(!bvecs))
- return;
+ unsigned vcnt = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
+ int i = 0;
+ struct bio *behind_bio = NULL;
+
+ behind_bio = bio_alloc_mddev(GFP_NOIO, vcnt, r1_bio->mddev);
+ if (!behind_bio)
+ goto fail;
+
+ while (i < vcnt && size) {
+ struct page *page;
+ int len = min_t(int, PAGE_SIZE, size);
+
+ page = alloc_page(GFP_NOIO);
+ if (unlikely(!page))
+ goto free_pages;
+
+ bio_add_page(behind_bio, page, len, 0);
+
+ size -= len;
+ i++;
+ }
- bio_for_each_segment_all(bvec, bio, i) {
- bvecs[i] = *bvec;
- bvecs[i].bv_page = alloc_page(GFP_NOIO);
- if (unlikely(!bvecs[i].bv_page))
- goto do_sync_io;
- memcpy(kmap(bvecs[i].bv_page) + bvec->bv_offset,
- kmap(bvec->bv_page) + bvec->bv_offset, bvec->bv_len);
- kunmap(bvecs[i].bv_page);
- kunmap(bvec->bv_page);
- }
- r1_bio->behind_bvecs = bvecs;
- r1_bio->behind_page_count = bio->bi_vcnt;
+ bio_copy_data_partial(behind_bio, bio, offset,
+ behind_bio->bi_iter.bi_size);
+
+ r1_bio->behind_master_bio = behind_bio;;
set_bit(R1BIO_BehindIO, &r1_bio->state);
- return;
-do_sync_io:
- for (i = 0; i < bio->bi_vcnt; i++)
- if (bvecs[i].bv_page)
- put_page(bvecs[i].bv_page);
- kfree(bvecs);
+ return behind_bio;
+
+free_pages:
pr_debug("%dB behind alloc failed, doing sync I/O\n",
bio->bi_iter.bi_size);
+ bio_free_pages(behind_bio);
+fail:
+ return behind_bio;
}
struct raid1_plug_cb {
@@ -1457,11 +1465,9 @@ static void raid1_write_request(struct mddev *mddev, struct bio *bio)
(atomic_read(&bitmap->behind_writes)
< mddev->bitmap_info.max_write_behind) &&
!waitqueue_active(&bitmap->behind_wait)) {
- mbio = bio_clone_bioset_partial(bio, GFP_NOIO,
- mddev->bio_set,
- offset << 9,
- max_sectors << 9);
- alloc_behind_pages(mbio, r1_bio);
+ mbio = alloc_behind_master_bio(r1_bio, bio,
+ offset << 9,
+ max_sectors << 9);
}
bitmap_startwrite(bitmap, r1_bio->sector,
@@ -1472,26 +1478,17 @@ static void raid1_write_request(struct mddev *mddev, struct bio *bio)
}
if (!mbio) {
- if (r1_bio->behind_bvecs)
- mbio = bio_clone_bioset_partial(bio, GFP_NOIO,
- mddev->bio_set,
- offset << 9,
- max_sectors << 9);
+ if (r1_bio->behind_master_bio)
+ mbio = bio_clone_fast(r1_bio->behind_master_bio,
+ GFP_NOIO,
+ mddev->bio_set);
else {
mbio = bio_clone_fast(bio, GFP_NOIO, mddev->bio_set);
bio_trim(mbio, offset, max_sectors);
}
}
- if (r1_bio->behind_bvecs) {
- struct bio_vec *bvec;
- int j;
-
- /*
- * We trimmed the bio, so _all is legit
- */
- bio_for_each_segment_all(bvec, mbio, j)
- bvec->bv_page = r1_bio->behind_bvecs[j].bv_page;
+ if (r1_bio->behind_master_bio) {
if (test_bit(WriteMostly, &conf->mirrors[i].rdev->flags))
atomic_inc(&r1_bio->behind_remaining);
}
@@ -2386,18 +2383,11 @@ static int narrow_write_error(struct r1bio *r1_bio, int i)
/* Write at 'sector' for 'sectors'*/
if (test_bit(R1BIO_BehindIO, &r1_bio->state)) {
- unsigned vcnt = r1_bio->behind_page_count;
- struct bio_vec *vec = r1_bio->behind_bvecs;
-
- while (!vec->bv_page) {
- vec++;
- vcnt--;
- }
-
- wbio = bio_alloc_mddev(GFP_NOIO, vcnt, mddev);
- memcpy(wbio->bi_io_vec, vec, vcnt * sizeof(struct bio_vec));
-
- wbio->bi_vcnt = vcnt;
+ wbio = bio_clone_fast(r1_bio->behind_master_bio,
+ GFP_NOIO,
+ mddev->bio_set);
+ /* We really need a _all clone */
+ wbio->bi_iter = (struct bvec_iter){ 0 };
} else {
wbio = bio_clone_fast(r1_bio->master_bio, GFP_NOIO,
mddev->bio_set);