[PATCH 2/2] lightnvm: pblk: kick writer on new flush points

From: Hans Holmberg
Date: Mon Apr 16 2018 - 12:46:58 EST


From: Hans Holmberg <hans.holmberg@xxxxxxxxxxxx>

Unless we kick the writer directly when setting a new flush point, the
user risks having to wait for up to one second (the default timeout for
the write thread to be kicked) for the IO to complete.

Signed-off-by: Hans Holmberg <hans.holmberg@xxxxxxxxxxxx>
---
drivers/lightnvm/pblk-cache.c | 10 ++++++----
drivers/lightnvm/pblk-core.c | 2 +-
drivers/lightnvm/pblk-rb.c | 4 ++--
drivers/lightnvm/pblk.h | 1 +
4 files changed, 10 insertions(+), 7 deletions(-)

diff --git a/drivers/lightnvm/pblk-cache.c b/drivers/lightnvm/pblk-cache.c
index 29a2311..b1c6d7e 100644
--- a/drivers/lightnvm/pblk-cache.c
+++ b/drivers/lightnvm/pblk-cache.c
@@ -44,13 +44,15 @@ int pblk_write_to_cache(struct pblk *pblk, struct bio *bio, unsigned long flags)
goto out;
}

- if (unlikely(!bio_has_data(bio)))
- goto out;
-
pblk_ppa_set_empty(&w_ctx.ppa);
w_ctx.flags = flags;
- if (bio->bi_opf & REQ_PREFLUSH)
+ if (bio->bi_opf & REQ_PREFLUSH) {
w_ctx.flags |= PBLK_FLUSH_ENTRY;
+ pblk_write_kick(pblk);
+ }
+
+ if (unlikely(!bio_has_data(bio)))
+ goto out;

for (i = 0; i < nr_entries; i++) {
void *data = bio_data(bio);
diff --git a/drivers/lightnvm/pblk-core.c b/drivers/lightnvm/pblk-core.c
index 94d5d97..ceacd10 100644
--- a/drivers/lightnvm/pblk-core.c
+++ b/drivers/lightnvm/pblk-core.c
@@ -320,7 +320,7 @@ int pblk_bio_add_pages(struct pblk *pblk, struct bio *bio, gfp_t flags,
return -1;
}

-static void pblk_write_kick(struct pblk *pblk)
+void pblk_write_kick(struct pblk *pblk)
{
wake_up_process(pblk->writer_ts);
mod_timer(&pblk->wtimer, jiffies + msecs_to_jiffies(1000));
diff --git a/drivers/lightnvm/pblk-rb.c b/drivers/lightnvm/pblk-rb.c
index 52fdd85..7a63291 100644
--- a/drivers/lightnvm/pblk-rb.c
+++ b/drivers/lightnvm/pblk-rb.c
@@ -350,7 +350,7 @@ void pblk_rb_write_entry_gc(struct pblk_rb *rb, void *data,
}

static int pblk_rb_flush_point_set(struct pblk_rb *rb, struct bio *bio,
- unsigned int pos)
+ unsigned int pos)
{
struct pblk_rb_entry *entry;
unsigned int sync, flush_point;
@@ -420,7 +420,7 @@ void pblk_rb_flush(struct pblk_rb *rb)
if (pblk_rb_flush_point_set(rb, NULL, mem))
return;

- pblk_write_should_kick(pblk);
+ pblk_write_kick(pblk);
}

static int pblk_rb_may_write_flush(struct pblk_rb *rb, unsigned int nr_entries,
diff --git a/drivers/lightnvm/pblk.h b/drivers/lightnvm/pblk.h
index 9c682ac..856ac41 100644
--- a/drivers/lightnvm/pblk.h
+++ b/drivers/lightnvm/pblk.h
@@ -837,6 +837,7 @@ void pblk_map_rq(struct pblk *pblk, struct nvm_rq *rqd, unsigned int sentry,
int pblk_write_ts(void *data);
void pblk_write_timer_fn(struct timer_list *t);
void pblk_write_should_kick(struct pblk *pblk);
+void pblk_write_kick(struct pblk *pblk);

/*
* pblk read path
--
2.7.4