On Fri, 30 Mar 2012 13:53:05 +0800 "majianpeng" <majianpeng@xxxxxxxxx> wrote:
> >From d5c0ad3ac03c805747f71338d30282f9f8d8d953 Mon Sep 17 00:00:00 2001
> From: majianpeng <majianpeng@xxxxxxxxx>
> Date: Fri, 30 Mar 2012 13:37:42 +0800
> Subject: [PATCH] md/raid1:When allocating resync pages,judge the queue limit of mddev.
> When max_sectors of mddev is smaller than
> RESYNC_PAGES(at present 64k),then: 1:alloc enough resync
> pags. 2:when do bio_add_page can goto bio_fill.
>
>
> Signed-off-by: majianpeng <majianpeng@xxxxxxxxx>
> ---
> drivers/md/raid1.c | 18 +++++++++++-------
> 1 files changed, 11 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
> index 4a40a20..cd100e6 100644
> --- a/drivers/md/raid1.c
> +++ b/drivers/md/raid1.c
> @@ -82,16 +82,19 @@ static void * r1buf_pool_alloc(gfp_t gfp_flags, void *data)
> struct r1bio *r1_bio;
> struct bio *bio;
> int i, j;
> + int sync_pages;
>
> r1_bio = r1bio_pool_alloc(gfp_flags, pi);
> if (!r1_bio)
> return NULL;
>
> + sync_pages = queue_max_sectors(pi->mddev->gendisk->queue) << 9;
I don't thing '<< 9' is correct. Maybe '<< (PAGE_SHIFT - 9)'.
> + sync_pages = min(RESYNC_PAGES, (sync_pages + PAGE_SIZE - 1) / PAGE_SIZE);
And this is definitely wrong. you don't want to round up the number of page
to be a multiple of the number of bytes in a page....
What is the value of this patch? It allocates a few fewer pages for the rare
case where the device cannot accept 64K IO requests?
I don't think it is really worth it, and given the obvious bugs, I won't
apply it.
Thanks,
NeilBrown
> /*
> * Allocate bios : 1 for reading, n-1 for writing
> */
> for (j = pi->raid_disks ; j-- ; ) {
> - bio = bio_kmalloc(gfp_flags, RESYNC_PAGES);
> + bio = bio_kmalloc(gfp_flags, sync_pages);
> if (!bio)
> goto out_free_bio;
> r1_bio->bios[j] = bio;
> @@ -108,7 +111,7 @@ static void * r1buf_pool_alloc(gfp_t gfp_flags, void *data)
> j = 1;
> while(j--) {
> bio = r1_bio->bios[j];
> - for (i = 0; i < RESYNC_PAGES; i++) {
> + for (i = 0; i < sync_pages; i++) {
> page = alloc_page(gfp_flags);
> if (unlikely(!page))
> goto out_free_pages;
> @@ -119,8 +122,8 @@ static void * r1buf_pool_alloc(gfp_t gfp_flags, void *data)
> }
> /* If not user-requests, copy the page pointers to all bios */
> if (!test_bit(MD_RECOVERY_REQUESTED, &pi->mddev->recovery)) {
> - for (i=0; i<RESYNC_PAGES ; i++)
> - for (j=1; j<pi->raid_disks; j++)
> + for (i = 0; i < sync_pages ; i++)
> + for (j = 1; j < pi->raid_disks; j++)
> r1_bio->bios[j]->bi_io_vec[i].bv_page =
> r1_bio->bios[0]->bi_io_vec[i].bv_page;
> }
> @@ -147,7 +150,7 @@ static void r1buf_pool_free(void *__r1_bio, void *data)
> int i,j;
> struct r1bio *r1bio = __r1_bio;
>
> - for (i = 0; i < RESYNC_PAGES; i++)
> + for (i = 0; i < r1bio->bios[0]->bi_max_vecs; i++)
> for (j = pi->raid_disks; j-- ;) {
> if (j == 0 ||
> r1bio->bios[j]->bi_io_vec[i].bv_page !=
> @@ -2243,7 +2246,7 @@ static sector_t sync_request(struct mddev *mddev, sector_t sector_nr, int *skipp
> int write_targets = 0, read_targets = 0;
> sector_t sync_blocks;
> int still_degraded = 0;
> - int good_sectors = RESYNC_SECTORS;
> + int good_sectors;
> int min_bad = 0; /* number of sectors that are bad in all devices */
>
> if (!conf->r1buf_pool)
> @@ -2296,6 +2299,7 @@ static sector_t sync_request(struct mddev *mddev, sector_t sector_nr, int *skipp
> r1_bio = mempool_alloc(conf->r1buf_pool, GFP_NOIO);
> raise_barrier(conf);
>
> + good_sectors = r1_bio->bios[0]->bi_max_vecs << 9;
> conf->next_resync = sector_nr;
>
> rcu_read_lock();
> @@ -2477,7 +2481,7 @@ static sector_t sync_request(struct mddev *mddev, sector_t sector_nr, int *skipp
> nr_sectors += len>>9;
> sector_nr += len>>9;
> sync_blocks -= (len>>9);
> - } while (r1_bio->bios[disk]->bi_vcnt < RESYNC_PAGES);
> + } while (r1_bio->bios[disk]->bi_vcnt < r1_bio->bios[0]->bi_max_vecs);
> bio_full:
> r1_bio->sectors = nr_sectors;
>
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