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The checks in nfsd_file_acquire() and nfsd_file_put() that directly invoke filecache garbage collection are intended to keep cache occupancy between a low- and high-watermark. The reason to limit the capacity of the filecache is to keep filecache lookups reasonably fast. However, invoking garbage collection at those points has some undesirable negative impacts. Files that are held open by NFSv4 clients often push the occupancy of the filecache over these watermarks. At that point: - Every call to nfsd_file_acquire() and nfsd_file_put() results in an LRU walk. This has the same effect on lookup latency as long chains in the hash table. - Garbage collection will then run on every nfsd thread, causing a lot of unnecessary lock contention. - Limiting cache capacity pushes out files used only by NFSv3 clients, which are the type of files the filecache is supposed to help. To address those negative impacts, remove the direct calls to the garbage collector. Subsequent patches will address maintaining lookup efficiency as cache capacity increases. Suggested-by: Wang Yugui <wangyugui@e16-tech.com> Suggested-by: Dave Chinner <david@fromorbit.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Chuck Lever <chuck.lever@oracle.com> |
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| .. | ||
| acl.h | ||
| auth.c | ||
| auth.h | ||
| blocklayout.c | ||
| blocklayoutxdr.c | ||
| blocklayoutxdr.h | ||
| cache.h | ||
| current_stateid.h | ||
| export.c | ||
| export.h | ||
| fault_inject.c | ||
| filecache.c | ||
| filecache.h | ||
| flexfilelayout.c | ||
| flexfilelayoutxdr.c | ||
| flexfilelayoutxdr.h | ||
| idmap.h | ||
| Kconfig | ||
| lockd.c | ||
| Makefile | ||
| netns.h | ||
| nfs2acl.c | ||
| nfs3acl.c | ||
| nfs3proc.c | ||
| nfs3xdr.c | ||
| nfs4acl.c | ||
| nfs4callback.c | ||
| nfs4idmap.c | ||
| nfs4layouts.c | ||
| nfs4proc.c | ||
| nfs4recover.c | ||
| nfs4state.c | ||
| nfs4xdr.c | ||
| nfscache.c | ||
| nfsctl.c | ||
| nfsd.h | ||
| nfsfh.c | ||
| nfsfh.h | ||
| nfsproc.c | ||
| nfssvc.c | ||
| nfsxdr.c | ||
| pnfs.h | ||
| state.h | ||
| stats.c | ||
| stats.h | ||
| trace.c | ||
| trace.h | ||
| vfs.c | ||
| vfs.h | ||
| xdr3.h | ||
| xdr4.h | ||
| xdr4cb.h | ||
| xdr.h | ||