From b20ba1bc749ce0cd7a74d24f23826a6462c3de53 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Javier=20Gonz=C3=A1lez?= Date: Mon, 26 Jun 2017 11:57:27 +0200 Subject: lightnvm: pblk: redesign GC algorithm MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit At the moment, in order to get enough read parallelism, we have recycled several lines at the same time. This approach has proven not to work well when reaching capacity, since we end up mixing valid data from all lines, thus not maintaining a sustainable free/recycled line ratio. The new design, relies on a two level workqueue mechanism. In the first level, we read the metadata for a number of lines based on the GC list they reside on (this is governed by the number of valid sectors in each line). In the second level, we recycle a single line at a time. Here, we issue reads in parallel, while a single GC write thread places data in the write buffer. This design allows to (i) only move data from one line at a time, thus maintaining a sane free/recycled ration and (ii) maintain the GC writer busy with recycled data. Signed-off-by: Javier González Signed-off-by: Matias Bjørling Signed-off-by: Jens Axboe --- drivers/lightnvm/pblk-core.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) (limited to 'drivers/lightnvm/pblk-core.c') diff --git a/drivers/lightnvm/pblk-core.c b/drivers/lightnvm/pblk-core.c index ed41cd7700b3..ba3b88f0e1f7 100644 --- a/drivers/lightnvm/pblk-core.c +++ b/drivers/lightnvm/pblk-core.c @@ -302,12 +302,12 @@ struct list_head *pblk_line_gc_list(struct pblk *pblk, struct pblk_line *line) line->gc_group = PBLK_LINEGC_FULL; move_list = &l_mg->gc_full_list; } - } else if (vsc < lm->mid_thrs) { + } else if (vsc < lm->high_thrs) { if (line->gc_group != PBLK_LINEGC_HIGH) { line->gc_group = PBLK_LINEGC_HIGH; move_list = &l_mg->gc_high_list; } - } else if (vsc < lm->high_thrs) { + } else if (vsc < lm->mid_thrs) { if (line->gc_group != PBLK_LINEGC_MID) { line->gc_group = PBLK_LINEGC_MID; move_list = &l_mg->gc_mid_list; @@ -1199,6 +1199,7 @@ retry_get: if (pblk_line_prepare(pblk, line)) { pr_err("pblk: failed to prepare line %d\n", line->id); list_add(&line->list, &l_mg->free_list); + l_mg->nr_free_lines++; return NULL; } @@ -1465,6 +1466,8 @@ void pblk_line_close(struct pblk *pblk, struct pblk_line *line) spin_unlock(&line->lock); spin_unlock(&l_mg->gc_lock); + + pblk_gc_should_kick(pblk); } void pblk_line_close_meta(struct pblk *pblk, struct pblk_line *line) -- cgit v1.2.2