tree 61e2b6fac3c9dd0f211c07f024fe5cb17ff5d3cf
parent ae30c286553c91c49af5cbc0265a05a6543d0c52
author Vivek Goyal <vgoyal@redhat.com> 1259863196 -0500
committer Jens Axboe <jens.axboe@oracle.com> 1259864933 +0100

blkio: Wait on sync-noidle queue even if rq_noidle = 1

o rq_noidle() is supposed to tell cfq that do not expect a request after this
  one, hence don't idle. But this does not seem to work very well. For example
  for direct random readers, rq_noidle = 1 but there is next request coming
  after this. Not idling, leads to a group not getting its share even if
  group_isolation=1.

o The right solution for this issue is to scan the higher layers and set
  right flag (WRITE_SYNC or WRITE_ODIRECT). For the time being, this single
  line fix helps. This should not have any significant impact when we are
  not using cgroups. I will later figure out IO paths in higher layer and
  fix it.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>