Fix linux filesystem cache calculation #73
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Linux's "Cached" statistic in /proc/meminfo is highly misleading as it contains swap-backed shmem. This is hard to reclaim at best, and not at all reclaimable on systems without swap. It should be considered actual_used, not actual_free. A more reliable filesystem cache footprint can be calculated from the file LRUs and the reclaimable slab cache, which is mostly filesystem metadata like dentries and inodes.
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Linux's "Cached" statistic in /proc/meminfo is highly misleading as it
contains swap-backed shmem. This is hard to reclaim at best, and not
at all reclaimable on systems without swap. It should be considered
actual_used, not actual_free.
A more reliable filesystem cache footprint can be calculated from the
file LRUs and the reclaimable slab cache, which is mostly filesystem
metadata like dentries and inodes.