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authorDavid Howells <dhowells@redhat.com>2009-11-19 18:11:19 +0000
committerDavid Howells <dhowells@redhat.com>2009-11-19 18:11:19 +0000
commit5753c441889253e4323eee85f791a1d64cf08196 (patch)
tree55a0de053d0593d96e99710f978277df668412d1 /Documentation
parentb34df792b4e9e311db47fad27949095d0629c197 (diff)
FS-Cache: Permit cache retrieval ops to be interrupted in the initial wait phase
Permit the operations to retrieve data from the cache or to allocate space in the cache for future writes to be interrupted whilst they're waiting for permission for the operation to proceed. Typically this wait occurs whilst the cache object is being looked up on disk in the background. If an interruption occurs, and the operation has not yet been given the go-ahead to run, the operation is dequeued and cancelled, and control returns to the read operation of the netfs routine with none of the requested pages having been read or in any way marked as known by the cache. This means that the initial wait is done interruptibly rather than uninterruptibly. In addition, extra stats values are made available to show the number of ops cancelled and the number of cache space allocations interrupted. Signed-off-by: David Howells <dhowells@redhat.com>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/filesystems/caching/fscache.txt2
1 files changed, 2 insertions, 0 deletions
diff --git a/Documentation/filesystems/caching/fscache.txt b/Documentation/filesystems/caching/fscache.txt
index b6c32c080ab..0a77868f497 100644
--- a/Documentation/filesystems/caching/fscache.txt
+++ b/Documentation/filesystems/caching/fscache.txt
@@ -250,6 +250,7 @@ proc files.
ok=N Number of successful alloc reqs
wt=N Number of alloc reqs that waited on lookup completion
nbf=N Number of alloc reqs rejected -ENOBUFS
+ int=N Number of alloc reqs aborted -ERESTARTSYS
ops=N Number of alloc reqs submitted
owt=N Number of alloc reqs waited for CPU time
Retrvls n=N Number of retrieval (read) requests seen
@@ -271,6 +272,7 @@ proc files.
Ops pend=N Number of times async ops added to pending queues
run=N Number of times async ops given CPU time
enq=N Number of times async ops queued for processing
+ can=N Number of async ops cancelled
dfr=N Number of async ops queued for deferred release
rel=N Number of async ops released
gc=N Number of deferred-release async ops garbage collected