NFS: Don't run wake_up_bit() when nobody is waiting...
authorTrond Myklebust <trond.myklebust@primarydata.com>
Tue, 11 Jul 2017 21:53:48 +0000 (17:53 -0400)
committerAnna Schumaker <Anna.Schumaker@Netapp.com>
Thu, 13 Jul 2017 20:57:18 +0000 (16:57 -0400)
commit301bfa483016d48b7fb9cbad87c0a04a15c25b90
tree1e86b94a773529cae5a3144e03ff7b35f7673188
parent00422483ad415d6267d36711f0e51f4bbbd653ed
NFS: Don't run wake_up_bit() when nobody is waiting...

"perf lock" shows fairly heavy contention for the bit waitqueue locks
when doing an I/O heavy workload.
Use a bit to tell whether or not there has been contention for a lock
so that we can optimise away the bit waitqueue options in those cases.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
fs/nfs/pagelist.c
include/linux/nfs_page.h