lightnvm: pblk: add debug stat for read cache hits

Add a new debug counter to measure cache hits on the read path

Signed-off-by: Javier González <javier@cnexlabs.com>
Signed-off-by: Matias Bjørling <matias@cnexlabs.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/drivers/lightnvm/pblk-init.c b/drivers/lightnvm/pblk-init.c
index aaefbcc..2d79336 100644 (file)
--- a/drivers/lightnvm/pblk-init.c
+++ b/drivers/lightnvm/pblk-init.c
@@ -839,6 +839,7 @@ static void *pblk_init(struct nvm_tgt_dev *dev, struct gendisk *tdisk,
        atomic_long_set(&pblk->sync_writes, 0);
        atomic_long_set(&pblk->compl_writes, 0);
        atomic_long_set(&pblk->inflight_reads, 0);
+       atomic_long_set(&pblk->cache_reads, 0);
        atomic_long_set(&pblk->sync_reads, 0);
        atomic_long_set(&pblk->recov_writes, 0);
        atomic_long_set(&pblk->recov_writes, 0);

diff --git a/drivers/lightnvm/pblk-read.c b/drivers/lightnvm/pblk-read.c
index 74d3fc5..f12f40a 100644 (file)
--- a/drivers/lightnvm/pblk-read.c
+++ b/drivers/lightnvm/pblk-read.c
@@ -76,6 +76,9 @@ retry:
                        }
                        WARN_ON(test_and_set_bit(i, read_bitmap));
                        advanced_bio = 1;
+#ifdef CONFIG_NVM_DEBUG
+                       atomic_long_inc(&pblk->cache_reads);
+#endif
                } else {
                        /* Read from media non-cached sectors */
                        rqd->ppa_list[j++] = p;
@@ -280,6 +283,9 @@ retry:
                        goto retry;
                }
                WARN_ON(test_and_set_bit(0, read_bitmap));
+#ifdef CONFIG_NVM_DEBUG
+                       atomic_long_inc(&pblk->cache_reads);
+#endif
        } else {
                rqd->ppa_addr = ppa;
        }

diff --git a/drivers/lightnvm/pblk-sysfs.c b/drivers/lightnvm/pblk-sysfs.c
index f0af1d1..3c1a586 100644 (file)
--- a/drivers/lightnvm/pblk-sysfs.c
+++ b/drivers/lightnvm/pblk-sysfs.c
@@ -294,7 +294,7 @@ static ssize_t pblk_sysfs_lines_info(struct pblk *pblk, char *page)
 static ssize_t pblk_sysfs_stats_debug(struct pblk *pblk, char *page)
 {
        return snprintf(page, PAGE_SIZE,
-               "%lu\t%lu\t%lu\t%lu\t%lu\t%lu\t%lu\t%lu\t%lu\t%lu\t%lu\t%lu\t%lu\n",
+               "%lu\t%lu\t%lu\t%lu\t%lu\t%lu\t%lu\t%lu\t%lu\t%lu\t%lu\t%lu\t%lu\t%lu\n",
                        atomic_long_read(&pblk->inflight_writes),
                        atomic_long_read(&pblk->inflight_reads),
                        atomic_long_read(&pblk->req_writes),
@@ -307,6 +307,7 @@ static ssize_t pblk_sysfs_stats_debug(struct pblk *pblk, char *page)
                        atomic_long_read(&pblk->recov_writes),
                        atomic_long_read(&pblk->recov_gc_writes),
                        atomic_long_read(&pblk->recov_gc_reads),
+                       atomic_long_read(&pblk->cache_reads),
                        atomic_long_read(&pblk->sync_reads));
 }
 #endif

diff --git a/drivers/lightnvm/pblk.h b/drivers/lightnvm/pblk.h
index 95b665f..77ee42a 100644 (file)
--- a/drivers/lightnvm/pblk.h
+++ b/drivers/lightnvm/pblk.h
@@ -513,6 +513,7 @@ struct pblk {
        atomic_long_t sync_writes;      /* Sectors synced to media */
        atomic_long_t compl_writes;     /* Sectors completed in write bio */
        atomic_long_t inflight_reads;   /* Inflight sector read requests */
+       atomic_long_t cache_reads;      /* Read requests that hit the cache */
        atomic_long_t sync_reads;       /* Completed sector read requests */
        atomic_long_t recov_writes;     /* Sectors submitted from recovery */
        atomic_long_t recov_gc_writes;  /* Sectors submitted from write GC */