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author | Hans Holmberg <hans.holmberg@cnexlabs.com> | 2018-12-11 20:16:13 +0100 |
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committer | Jens Axboe <axboe@kernel.dk> | 2018-12-11 12:22:33 -0700 |
commit | 3bcebc5bac0935d662f30d317e33ffa660bebf93 (patch) | |
tree | a253b85173c905425e6dc5bcdd285399faa2419f /drivers/lightnvm/pblk-init.c | |
parent | 525f7bb2c9f9b2c6673854eade89e98fb3ba7802 (diff) | |
download | linux-3bcebc5bac0935d662f30d317e33ffa660bebf93.tar.gz linux-3bcebc5bac0935d662f30d317e33ffa660bebf93.tar.bz2 linux-3bcebc5bac0935d662f30d317e33ffa660bebf93.zip |
lightnvm: pblk: set conservative threshold for user writes
In a worst-case scenario (random writes), OP% of sectors
in each line will be invalid, and we will then need
to move data out of 100/OP% lines to free a single line.
So, to prevent the possibility of running out of lines,
temporarily block user writes when there is less than
100/OP% free lines.
Also ensure that pblk creation does not produce instances
with insufficient over provisioning.
Insufficient over-provising is not a problem on real hardware,
but often an issue when running QEMU simulations (with few lines).
100 lines is enough to create a sane instance with the standard
(11%) over provisioning.
Signed-off-by: Hans Holmberg <hans.holmberg@cnexlabs.com>
Reviewed-by: Javier González <javier@javigon.com>
Signed-off-by: Matias Bjørling <mb@lightnvm.io>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'drivers/lightnvm/pblk-init.c')
-rw-r--r-- | drivers/lightnvm/pblk-init.c | 40 |
1 files changed, 31 insertions, 9 deletions
diff --git a/drivers/lightnvm/pblk-init.c b/drivers/lightnvm/pblk-init.c index 13822594647c..f083130d9920 100644 --- a/drivers/lightnvm/pblk-init.c +++ b/drivers/lightnvm/pblk-init.c @@ -635,7 +635,7 @@ static unsigned int calc_emeta_len(struct pblk *pblk) return (lm->emeta_len[1] + lm->emeta_len[2] + lm->emeta_len[3]); } -static void pblk_set_provision(struct pblk *pblk, long nr_free_blks) +static int pblk_set_provision(struct pblk *pblk, int nr_free_chks) { struct nvm_tgt_dev *dev = pblk->dev; struct pblk_line_mgmt *l_mg = &pblk->l_mg; @@ -643,23 +643,41 @@ static void pblk_set_provision(struct pblk *pblk, long nr_free_blks) struct nvm_geo *geo = &dev->geo; sector_t provisioned; int sec_meta, blk_meta; + int minimum; if (geo->op == NVM_TARGET_DEFAULT_OP) pblk->op = PBLK_DEFAULT_OP; else pblk->op = geo->op; - provisioned = nr_free_blks; + minimum = pblk_get_min_chks(pblk); + provisioned = nr_free_chks; provisioned *= (100 - pblk->op); sector_div(provisioned, 100); - pblk->op_blks = nr_free_blks - provisioned; + if ((nr_free_chks - provisioned) < minimum) { + if (geo->op != NVM_TARGET_DEFAULT_OP) { + pblk_err(pblk, "OP too small to create a sane instance\n"); + return -EINTR; + } + + /* If the user did not specify an OP value, and PBLK_DEFAULT_OP + * is not enough, calculate and set sane value + */ + + provisioned = nr_free_chks - minimum; + pblk->op = (100 * minimum) / nr_free_chks; + pblk_info(pblk, "Default OP insufficient, adjusting OP to %d\n", + pblk->op); + } + + pblk->op_blks = nr_free_chks - provisioned; /* Internally pblk manages all free blocks, but all calculations based * on user capacity consider only provisioned blocks */ - pblk->rl.total_blocks = nr_free_blks; - pblk->rl.nr_secs = nr_free_blks * geo->clba; + pblk->rl.total_blocks = nr_free_chks; + pblk->rl.nr_secs = nr_free_chks * geo->clba; /* Consider sectors used for metadata */ sec_meta = (lm->smeta_sec + lm->emeta_sec[0]) * l_mg->nr_free_lines; @@ -667,8 +685,10 @@ static void pblk_set_provision(struct pblk *pblk, long nr_free_blks) pblk->capacity = (provisioned - blk_meta) * geo->clba; - atomic_set(&pblk->rl.free_blocks, nr_free_blks); - atomic_set(&pblk->rl.free_user_blocks, nr_free_blks); + atomic_set(&pblk->rl.free_blocks, nr_free_chks); + atomic_set(&pblk->rl.free_user_blocks, nr_free_chks); + + return 0; } static int pblk_setup_line_meta_chk(struct pblk *pblk, struct pblk_line *line, @@ -984,7 +1004,7 @@ static int pblk_lines_init(struct pblk *pblk) struct pblk_line_mgmt *l_mg = &pblk->l_mg; struct pblk_line *line; void *chunk_meta; - long nr_free_chks = 0; + int nr_free_chks = 0; int i, ret; ret = pblk_line_meta_init(pblk); @@ -1031,7 +1051,9 @@ static int pblk_lines_init(struct pblk *pblk) goto fail_free_lines; } - pblk_set_provision(pblk, nr_free_chks); + ret = pblk_set_provision(pblk, nr_free_chks); + if (ret) + goto fail_free_lines; vfree(chunk_meta); return 0; |