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2013-09-10shrinker: Kill old ->shrink API.Dave Chinner1-10/+5
There are no more users of this API, so kill it dead, dead, dead and quietly bury the corpse in a shallow, unmarked grave in a dark forest deep in the hills... [[email protected]: added flowers to the grave] Signed-off-by: Dave Chinner <[email protected]> Signed-off-by: Glauber Costa <[email protected]> Reviewed-by: Greg Thelen <[email protected]> Acked-by: Mel Gorman <[email protected]> Cc: "Theodore Ts'o" <[email protected]> Cc: Adrian Hunter <[email protected]> Cc: Al Viro <[email protected]> Cc: Artem Bityutskiy <[email protected]> Cc: Arve Hjønnevåg <[email protected]> Cc: Carlos Maiolino <[email protected]> Cc: Christoph Hellwig <[email protected]> Cc: Chuck Lever <[email protected]> Cc: Daniel Vetter <[email protected]> Cc: David Rientjes <[email protected]> Cc: Gleb Natapov <[email protected]> Cc: Greg Thelen <[email protected]> Cc: J. Bruce Fields <[email protected]> Cc: Jan Kara <[email protected]> Cc: Jerome Glisse <[email protected]> Cc: John Stultz <[email protected]> Cc: KAMEZAWA Hiroyuki <[email protected]> Cc: Kent Overstreet <[email protected]> Cc: Kirill A. Shutemov <[email protected]> Cc: Marcelo Tosatti <[email protected]> Cc: Mel Gorman <[email protected]> Cc: Steven Whitehouse <[email protected]> Cc: Thomas Hellstrom <[email protected]> Cc: Trond Myklebust <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Al Viro <[email protected]>
2013-09-10vmscan: per-node deferred workGlauber Costa1-2/+12
The list_lru infrastructure already keeps per-node LRU lists in its node-specific list_lru_node arrays and provide us with a per-node API, and the shrinkers are properly equiped with node information. This means that we can now focus our shrinking effort in a single node, but the work that is deferred from one run to another is kept global at nr_in_batch. Work can be deferred, for instance, during direct reclaim under a GFP_NOFS allocation, where situation, all the filesystem shrinkers will be prevented from running and accumulate in nr_in_batch the amount of work they should have done, but could not. This creates an impedance problem, where upon node pressure, work deferred will accumulate and end up being flushed in other nodes. The problem we describe is particularly harmful in big machines, where many nodes can accumulate at the same time, all adding to the global counter nr_in_batch. As we accumulate more and more, we start to ask for the caches to flush even bigger numbers. The result is that the caches are depleted and do not stabilize. To achieve stable steady state behavior, we need to tackle it differently. In this patch we keep the deferred count per-node, in the new array nr_deferred[] (the name is also a bit more descriptive) and will never accumulate that to other nodes. Signed-off-by: Glauber Costa <[email protected]> Cc: Dave Chinner <[email protected]> Cc: Mel Gorman <[email protected]> Cc: "Theodore Ts'o" <[email protected]> Cc: Adrian Hunter <[email protected]> Cc: Al Viro <[email protected]> Cc: Artem Bityutskiy <[email protected]> Cc: Arve Hjønnevåg <[email protected]> Cc: Carlos Maiolino <[email protected]> Cc: Christoph Hellwig <[email protected]> Cc: Chuck Lever <[email protected]> Cc: Daniel Vetter <[email protected]> Cc: David Rientjes <[email protected]> Cc: Gleb Natapov <[email protected]> Cc: Greg Thelen <[email protected]> Cc: J. Bruce Fields <[email protected]> Cc: Jan Kara <[email protected]> Cc: Jerome Glisse <[email protected]> Cc: John Stultz <[email protected]> Cc: KAMEZAWA Hiroyuki <[email protected]> Cc: Kent Overstreet <[email protected]> Cc: Kirill A. Shutemov <[email protected]> Cc: Marcelo Tosatti <[email protected]> Cc: Mel Gorman <[email protected]> Cc: Steven Whitehouse <[email protected]> Cc: Thomas Hellstrom <[email protected]> Cc: Trond Myklebust <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Al Viro <[email protected]>
2013-09-10shrinker: add node awarenessDave Chinner1-0/+3
Pass the node of the current zone being reclaimed to shrink_slab(), allowing the shrinker control nodemask to be set appropriately for node aware shrinkers. Signed-off-by: Dave Chinner <[email protected]> Signed-off-by: Glauber Costa <[email protected]> Acked-by: Mel Gorman <[email protected]> Cc: "Theodore Ts'o" <[email protected]> Cc: Adrian Hunter <[email protected]> Cc: Al Viro <[email protected]> Cc: Artem Bityutskiy <[email protected]> Cc: Arve Hjønnevåg <[email protected]> Cc: Carlos Maiolino <[email protected]> Cc: Christoph Hellwig <[email protected]> Cc: Chuck Lever <[email protected]> Cc: Daniel Vetter <[email protected]> Cc: David Rientjes <[email protected]> Cc: Gleb Natapov <[email protected]> Cc: Greg Thelen <[email protected]> Cc: J. Bruce Fields <[email protected]> Cc: Jan Kara <[email protected]> Cc: Jerome Glisse <[email protected]> Cc: John Stultz <[email protected]> Cc: KAMEZAWA Hiroyuki <[email protected]> Cc: Kent Overstreet <[email protected]> Cc: Kirill A. Shutemov <[email protected]> Cc: Marcelo Tosatti <[email protected]> Cc: Mel Gorman <[email protected]> Cc: Steven Whitehouse <[email protected]> Cc: Thomas Hellstrom <[email protected]> Cc: Trond Myklebust <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Al Viro <[email protected]>
2013-09-10mm: new shrinker APIDave Chinner1-9/+29
The current shrinker callout API uses an a single shrinker call for multiple functions. To determine the function, a special magical value is passed in a parameter to change the behaviour. This complicates the implementation and return value specification for the different behaviours. Separate the two different behaviours into separate operations, one to return a count of freeable objects in the cache, and another to scan a certain number of objects in the cache for freeing. In defining these new operations, ensure the return values and resultant behaviours are clearly defined and documented. Modify shrink_slab() to use the new API and implement the callouts for all the existing shrinkers. Signed-off-by: Dave Chinner <[email protected]> Signed-off-by: Glauber Costa <[email protected]> Acked-by: Mel Gorman <[email protected]> Cc: "Theodore Ts'o" <[email protected]> Cc: Adrian Hunter <[email protected]> Cc: Al Viro <[email protected]> Cc: Artem Bityutskiy <[email protected]> Cc: Arve Hjønnevåg <[email protected]> Cc: Carlos Maiolino <[email protected]> Cc: Christoph Hellwig <[email protected]> Cc: Chuck Lever <[email protected]> Cc: Daniel Vetter <[email protected]> Cc: David Rientjes <[email protected]> Cc: Gleb Natapov <[email protected]> Cc: Greg Thelen <[email protected]> Cc: J. Bruce Fields <[email protected]> Cc: Jan Kara <[email protected]> Cc: Jerome Glisse <[email protected]> Cc: John Stultz <[email protected]> Cc: KAMEZAWA Hiroyuki <[email protected]> Cc: Kent Overstreet <[email protected]> Cc: Kirill A. Shutemov <[email protected]> Cc: Marcelo Tosatti <[email protected]> Cc: Mel Gorman <[email protected]> Cc: Steven Whitehouse <[email protected]> Cc: Thomas Hellstrom <[email protected]> Cc: Trond Myklebust <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Al Viro <[email protected]>
2012-07-31vmscan: remove obsolete shrink_control commentMinchan Kim1-1/+0
09f363c7 ("vmscan: fix shrinker callback bug in fs/super.c") fixed a shrinker callback which was returning -1 when nr_to_scan is zero, which caused excessive slab scanning. But 635697c6 ("vmscan: fix initial shrinker size handling") fixed the problem, again so we can freely return -1 although nr_to_scan is zero. So let's revert 09f363c7 because the comment added in 09f363c7 made an unnecessary rule. Signed-off-by: Minchan Kim <[email protected]> Cc: Al Viro <[email protected]> Cc: Mikulas Patocka <[email protected]> Cc: Konstantin Khlebnikov <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
2011-12-09vmscan: use atomic-long for shrinker batchingKonstantin Khlebnikov1-1/+1
Use atomic-long operations instead of looping around cmpxchg(). [[email protected]: massage atomic.h inclusions] Signed-off-by: Konstantin Khlebnikov <[email protected]> Cc: Dave Chinner <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
2011-10-31vmscan: fix shrinker callback bug in fs/super.cMikulas Patocka1-0/+1
The callback must not return -1 when nr_to_scan is zero. Fix the bug in fs/super.c and add this requirement to the callback specification. Signed-off-by: Mikulas Patocka <[email protected]> Cc: Dave Chinner <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
2011-07-20superblock: introduce per-sb cache shrinker infrastructureDave Chinner1-0/+42
With context based shrinkers, we can implement a per-superblock shrinker that shrinks the caches attached to the superblock. We currently have global shrinkers for the inode and dentry caches that split up into per-superblock operations via a coarse proportioning method that does not batch very well. The global shrinkers also have a dependency - dentries pin inodes - so we have to be very careful about how we register the global shrinkers so that the implicit call order is always correct. With a per-sb shrinker callout, we can encode this dependency directly into the per-sb shrinker, hence avoiding the need for strictly ordering shrinker registrations. We also have no need for any proportioning code for the shrinker subsystem already provides this functionality across all shrinkers. Allowing the shrinker to operate on a single superblock at a time means that we do less superblock list traversals and locking and reclaim should batch more effectively. This should result in less CPU overhead for reclaim and potentially faster reclaim of items from each filesystem. Signed-off-by: Dave Chinner <[email protected]> Signed-off-by: Al Viro <[email protected]>