cluster/dht: don't overfill the buffer in readdir(p)

Superflous dentries that cannot be fit in the buffer size provided by
kernel are thrown away by fuse-bridge. This means,

* the next readdir(p) seen by readdir-ahead would have an offset of a
dentry returned in a previous readdir(p) response. When readdir-ahead
detects non-monotonic offset it turns itself off which can result in
poor readdir performance.

* readdirp can be cpu-intensive on brick and there is no point to read
 all those dentries just to be thrown away by fuse-bridge.

So, the best strategy would be to fill the buffer optimally - neither
overfill nor underfill.

Change-Id: Idb3d85dd4c08fdc4526b2df801d49e69e439ba84
BUG: 1492625
Signed-off-by: Raghavendra G <rgowdapp@redhat.com>

0 files changed, 0 insertions, 0 deletions