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authorHans Holmberg <hans.holmberg@cnexlabs.com>2018-12-11 22:16:13 +0300
committerJens Axboe <axboe@kernel.dk>2018-12-11 22:22:33 +0300
commit3bcebc5bac0935d662f30d317e33ffa660bebf93 (patch)
treea253b85173c905425e6dc5bcdd285399faa2419f /drivers/lightnvm/pblk.h
parent525f7bb2c9f9b2c6673854eade89e98fb3ba7802 (diff)
downloadlinux-3bcebc5bac0935d662f30d317e33ffa660bebf93.tar.xz
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.h')
-rw-r--r--drivers/lightnvm/pblk.h12
1 files changed, 11 insertions, 1 deletions
diff --git a/drivers/lightnvm/pblk.h b/drivers/lightnvm/pblk.h
index f415aae600c8..e5b88a25d4d6 100644
--- a/drivers/lightnvm/pblk.h
+++ b/drivers/lightnvm/pblk.h
@@ -905,7 +905,6 @@ int pblk_recov_check_emeta(struct pblk *pblk, struct line_emeta *emeta);
#define PBLK_GC_MAX_READERS 8 /* Max number of outstanding GC reader jobs */
#define PBLK_GC_RQ_QD 128 /* Queue depth for inflight GC requests */
#define PBLK_GC_L_QD 4 /* Queue depth for inflight GC lines */
-#define PBLK_GC_RSV_LINE 1 /* Reserved lines for GC */
int pblk_gc_init(struct pblk *pblk);
void pblk_gc_exit(struct pblk *pblk, bool graceful);
@@ -1370,4 +1369,15 @@ static inline char *pblk_disk_name(struct pblk *pblk)
return disk->disk_name;
}
+
+static inline unsigned int pblk_get_min_chks(struct pblk *pblk)
+{
+ struct pblk_line_meta *lm = &pblk->lm;
+ /* In a worst-case scenario every line will have OP invalid sectors.
+ * We will then need a minimum of 1/OP lines to free up a single line
+ */
+
+ return DIV_ROUND_UP(100, pblk->op) * lm->blk_per_line;
+
+}
#endif /* PBLK_H_ */