/*
* pblk_rb_calculate_size -- calculate the size of the write buffer
*/
-static unsigned int pblk_rb_calculate_size(unsigned int nr_entries)
+static unsigned int pblk_rb_calculate_size(unsigned int nr_entries,
+ unsigned int threshold)
{
- /* Alloc a write buffer that can at least fit 128 entries */
- return (1 << max(get_count_order(nr_entries), 7));
+ unsigned int thr_sz = 1 << (get_count_order(threshold + NVM_MAX_VLBA));
+ unsigned int max_sz = max(thr_sz, nr_entries);
+ unsigned int max_io;
+
+ /* Alloc a write buffer that can (i) fit at least two split bios
+ * (considering max I/O size NVM_MAX_VLBA, and (ii) guarantee that the
+ * threshold will be respected
+ */
+ max_io = (1 << max((int)(get_count_order(max_sz)),
+ (int)(get_count_order(NVM_MAX_VLBA << 1))));
+ if ((threshold + NVM_MAX_VLBA) >= max_io)
+ max_io <<= 1;
+
+ return max_io;
}
/*
unsigned int alloc_order, order, iter;
unsigned int nr_entries;
- nr_entries = pblk_rb_calculate_size(size);
+ nr_entries = pblk_rb_calculate_size(size, threshold);
entries = vzalloc(array_size(nr_entries, sizeof(struct pblk_rb_entry)));
if (!entries)
return -ENOMEM;
- power_size = get_count_order(size);
+ power_size = get_count_order(nr_entries);
power_seg_sz = get_count_order(seg_size);
down_write(&pblk_rb_lock);
* Initialize rate-limiter, which controls access to the write buffer
* by user and GC I/O
*/
- pblk_rl_init(&pblk->rl, rb->nr_entries);
+ pblk_rl_init(&pblk->rl, rb->nr_entries, threshold);
return 0;
}
del_timer(&rl->u_timer);
}
-void pblk_rl_init(struct pblk_rl *rl, int budget)
+void pblk_rl_init(struct pblk_rl *rl, int budget, int threshold)
{
struct pblk *pblk = container_of(rl, struct pblk, rl);
struct nvm_tgt_dev *dev = pblk->dev;
int sec_meta, blk_meta;
unsigned int rb_windows;
-
/* Consider sectors used for metadata */
sec_meta = (lm->smeta_sec + lm->emeta_sec[0]) * l_mg->nr_free_lines;
blk_meta = DIV_ROUND_UP(sec_meta, geo->clba);
/* To start with, all buffer is available to user I/O writers */
rl->rb_budget = budget;
rl->rb_user_max = budget;
- rl->rb_max_io = budget >> 1;
+ rl->rb_max_io = threshold ? (budget - threshold) : (budget - 1);
rl->rb_gc_max = 0;
rl->rb_state = PBLK_RL_HIGH;
/*
* pblk rate limiter
*/
-void pblk_rl_init(struct pblk_rl *rl, int budget);
+void pblk_rl_init(struct pblk_rl *rl, int budget, int threshold);
void pblk_rl_free(struct pblk_rl *rl);
void pblk_rl_update_rates(struct pblk_rl *rl);
int pblk_rl_high_thrs(struct pblk_rl *rl);