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authorLinus Torvalds <torvalds@linux-foundation.org>2013-06-12 16:42:39 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2013-06-12 16:42:39 -0700
commitb2cc9c19e48bcf00f10c23fbf9f6abe43f6929d5 (patch)
treed38b1d04479c14c8a9bfdf01bc817490173dcd28 /Documentation/bcache.txt
parenta568fa1c91d4f0e565345119d0b942cc7f74ca3d (diff)
parentac4e97abce9b80c020e7113325f49e58b7b15e3f (diff)
Merge branch 'for-linus' of git://git.kernel.dk/linux-block
Pull block layer fixes from Jens Axboe: "Outside of bcache (which really isn't super big), these are all few-liners. There are a few important fixes in here: - Fix blk pm sleeping when holding the queue lock - A small collection of bcache fixes that have been done and tested since bcache was included in this merge window. - A fix for a raid5 regression introduced with the bio changes. - Two important fixes for mtip32xx, fixing an oops and potential data corruption (or hang) due to wrong bio iteration on stacked devices." * 'for-linus' of git://git.kernel.dk/linux-block: scatterlist: sg_set_buf() argument must be in linear mapping raid5: Initialize bi_vcnt pktcdvd: silence static checker warning block: remove refs to XD disks from documentation blkpm: avoid sleep when holding queue lock mtip32xx: Correctly handle bio->bi_idx != 0 conditions mtip32xx: Fix NULL pointer dereference during module unload bcache: Fix error handling in init code bcache: clarify free/available/unused space bcache: drop "select CLOSURES" bcache: Fix incompatible pointer type warning
Diffstat (limited to 'Documentation/bcache.txt')
-rw-r--r--Documentation/bcache.txt12
1 files changed, 9 insertions, 3 deletions
diff --git a/Documentation/bcache.txt b/Documentation/bcache.txt
index 77db8809bd96..b3a7e7d384f6 100644
--- a/Documentation/bcache.txt
+++ b/Documentation/bcache.txt
@@ -319,7 +319,10 @@ cache<0..n>
Symlink to each of the cache devices comprising this cache set.
cache_available_percent
- Percentage of cache device free.
+ Percentage of cache device which doesn't contain dirty data, and could
+ potentially be used for writeback. This doesn't mean this space isn't used
+ for clean cached data; the unused statistic (in priority_stats) is typically
+ much lower.
clear_stats
Clears the statistics associated with this cache
@@ -423,8 +426,11 @@ nbuckets
Total buckets in this cache
priority_stats
- Statistics about how recently data in the cache has been accessed. This can
- reveal your working set size.
+ Statistics about how recently data in the cache has been accessed.
+ This can reveal your working set size. Unused is the percentage of
+ the cache that doesn't contain any data. Metadata is bcache's
+ metadata overhead. Average is the average priority of cache buckets.
+ Next is a list of quantiles with the priority threshold of each.
written
Sum of all data that has been written to the cache; comparison with