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Document the idle cleaning support.

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1 parent 3cc2036 commit 8643738f1fdf06a2274f69cd1c8f620af728d071 Mohan Srinivasan committed Apr 6, 2011
Showing with 7 additions and 3 deletions.
  1. +4 −3 doc/flashcache-doc.txt
  2. +3 −0 doc/flashcache-sa-guide.txt
@@ -100,9 +100,10 @@ dirty threshold. When the dirty blocks in a set exceeds the dirty
threshold, the set is eligible for cleaning.
Dirty blocks are also cleaned based on "idleness" By defalt a
-dirty block not read or written for 60 seconds
-(dev.flashcache.fallow_delay) will be cleaned. To disable idle
-cleaning set that value to 0.
+dirty block not read or written for 15 minutes (dev.flashcache.fallow_delay)
+will be cleaned. To disable idle cleaning set that value to 0.
+A 2 handed clocklike algorithm is used to pick off fallow dirty
+blocks to clean.
DIRTY blocks are selected for cleaning based on the replacement policy
(FIFO vs LRU). Once we have a target set of blocks to clean, we sort
@@ -170,6 +170,9 @@ dev.flashcache.fallow_delay:
read or written) for fallow_delay seconds. Default is 60
Setting this to 0 disables idle cleaning completely.
+ The maximum number of "fallow clean" disk writes per set
+ per second. Defaults to 2.
Compute IO latencies and plot these out on a histogram.
The scale is 250 usecs. This is disabled by default since

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