Improve cache_status to emit:
<metadata block size> <#used metadata blocks>/<#total metadata blocks>
<cache block size> <#used cache blocks>/<#total cache blocks>
...
Adding the block sizes allows for easier calculation of the overall size
of both the metadata and cache devices. Adding <#total cache blocks>
provides useful context for how much of the cache is used.
While updating the status documentation in cache.txt spaces were
tabify'd.
Requested-by: Jonathan Brassow <jbrassow@xxxxxxxxxx>
Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx>
---
Documentation/device-mapper/cache.txt | 48 ++++++++++++++++++---------------
drivers/md/dm-cache-target.c | 14 ++++++---
2 files changed, 35 insertions(+), 27 deletions(-)
diff --git a/Documentation/device-mapper/cache.txt b/Documentation/device-mapper/cache.txt
index 719320b..742c4eb 100644
--- a/Documentation/device-mapper/cache.txt
+++ b/Documentation/device-mapper/cache.txt
@@ -217,36 +217,40 @@ the characteristics of a specific policy, always request it by name.
Status
------
-<#used metadata blocks>/<#total metadata blocks> <#read hits> <#read misses>
-<#write hits> <#write misses> <#demotions> <#promotions> <#blocks in cache>
-<#dirty> <#features> <features>* <#core args> <core args>* <#policy args>
-<policy args>*
-
-#used metadata blocks : Number of metadata blocks used
-#total metadata blocks : Total number of metadata blocks
-#read hits : Number of times a READ bio has been mapped
+<metadata block size> <#used metadata blocks>/<#total metadata blocks>
+<cache block size> <#used cache blocks>/<#total cache blocks>
+<#read hits> <#read misses> <#write hits> <#write misses>
+<#demotions> <#promotions> <#dirty> <#features> <features>*
+<#core args> <core args>* <#policy args> <policy args>*
+
+metadata block size : Fixed block size for each metadata block
+#used metadata blocks : Number of metadata blocks used
+#total metadata blocks : Total number of metadata blocks
+cache block size : Configurable block size for the cache device
+#used cache blocks : Number of blocks resident in the cache
+#total cache blocks : Total number of cache blocks
+#read hits : Number of times a READ bio has been mapped
to the cache
-#read misses : Number of times a READ bio has been mapped
+#read misses : Number of times a READ bio has been mapped
to the origin
-#write hits : Number of times a WRITE bio has been mapped
+#write hits : Number of times a WRITE bio has been mapped
to the cache
-#write misses : Number of times a WRITE bio has been
+#write misses : Number of times a WRITE bio has been
mapped to the origin
-#demotions : Number of times a block has been removed
+#demotions : Number of times a block has been removed
from the cache
-#promotions : Number of times a block has been moved to
+#promotions : Number of times a block has been moved to
the cache
-#blocks in cache : Number of blocks resident in the cache
-#dirty : Number of blocks in the cache that differ
+#dirty : Number of blocks in the cache that differ
from the origin
-#feature args : Number of feature args to follow
-feature args : 'writethrough' (optional)
-#core args : Number of core arguments (must be even)
-core args : Key/value pairs for tuning the core
+#feature args : Number of feature args to follow
+feature args : 'writethrough' (optional)
+#core args : Number of core arguments (must be even)
+core args : Key/value pairs for tuning the core
e.g. migration_threshold
-#policy args : Number of policy arguments to follow (must be even)
-policy args : Key/value pairs
- e.g. 'sequential_threshold 1024
+#policy args : Number of policy arguments to follow (must be even)
+policy args : Key/value pairs
+ e.g. sequential_threshold
Messages
--------
diff --git a/drivers/md/dm-cache-target.c b/drivers/md/dm-cache-target.c
index 1b1469e..9ad7a2f 100644
--- a/drivers/md/dm-cache-target.c
+++ b/drivers/md/dm-cache-target.c
@@ -2826,9 +2826,10 @@ static void cache_resume(struct dm_target *ti)
/*
* Status format:
*
- * <#used metadata blocks>/<#total metadata blocks>
+ * <metadata block size> <#used metadata blocks>/<#total metadata blocks>
+ * <cache block size> <#used cache blocks>/<#total cache blocks>
* <#read hits> <#read misses> <#write hits> <#write misses>
- * <#demotions> <#promotions> <#blocks in cache> <#dirty>
+ * <#demotions> <#promotions> <#dirty>
* <#features> <features>*
* <#core args> <core args>
* <#policy args> <policy args>*
@@ -2869,17 +2870,20 @@ static void cache_status(struct dm_target *ti, status_type_t type,
residency = policy_residency(cache->policy);
- DMEMIT("%llu/%llu %u %u %u %u %u %u %llu %u ",
+ DMEMIT("%u %llu/%llu %u %llu/%llu %u %u %u %u %u %u %llu ",
+ (unsigned)(DM_CACHE_METADATA_BLOCK_SIZE >> SECTOR_SHIFT),
(unsigned long long)(nr_blocks_metadata - nr_free_blocks_metadata),
(unsigned long long)nr_blocks_metadata,
+ cache->sectors_per_block,
+ (unsigned long long) from_cblock(residency),
+ (unsigned long long) from_cblock(cache->cache_size),
(unsigned) atomic_read(&cache->stats.read_hit),
(unsigned) atomic_read(&cache->stats.read_miss),
(unsigned) atomic_read(&cache->stats.write_hit),
(unsigned) atomic_read(&cache->stats.write_miss),
(unsigned) atomic_read(&cache->stats.demotion),
(unsigned) atomic_read(&cache->stats.promotion),
- (unsigned long long) from_cblock(residency),
- cache->nr_dirty);
+ (unsigned long long) from_cblock(cache->nr_dirty));
if (writethrough_mode(&cache->features))
DMEMIT("1 writethrough ");
--
1.7.4.4
--
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