On Sat, 24 Jan 2015 00:39:23 -0500 Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx> wrote: > Hi all, > > The following patchset improves the tracking of stateids in the CLOSE code > to ensure that we can rely on it in situations where we remove the NFSv4.0 > serialisation of state that shares the same open owners. > It then proceeds to add a series of changes to the NFSv4.0 seqid code to > ensure that it can be removed in the case of NFSv4.0 opens. > Only lightly tested so far, but it seems to be working... > > In principle there is nothing stopping us from doing the same with byte > range locks; we only need to add better atomicity of stateid updates, > so that we can track the seqid number in the stateid and ensure that it > never regresses. The exercise has been left for the reader... > > Cheers > Trond > > Trond Myklebust (5): > NFSv4: Fix an atomicity problem in CLOSE > NFSv4: More CLOSE/OPEN races > NFSv4: Convert nfs_alloc_seqid() to return an ERR_PTR() if allocation > fails > NFSv4: Check for NULL argument in nfs_*_seqid() functions > NFSv4.1: Allow parallel OPEN/OPEN_DOWNGRADE/CLOSE > > fs/nfs/nfs4_fs.h | 3 +++ > fs/nfs/nfs4proc.c | 50 ++++++++++++++++++++++++++++++++++++++++--------- > fs/nfs/nfs4state.c | 31 ++++++++++++++++++------------ > fs/nfs/nfs4xdr.c | 9 ++++++--- > include/linux/nfs_xdr.h | 2 +- > 5 files changed, 70 insertions(+), 25 deletions(-) > FWIW, I checked out your devel branch and built a kernel with it. I then ran a test that forks off a bunch of processes and has them create and close a number of files as rapidly as possible: Stock fedora 3.19.0-0.rc5.git2.1.fc22.x86_64: $ time ./opentest01 /mnt/rawhide/opentest/ real 1m46.203s user 0m0.745s sys 0m15.713s Trond's devel branch: $ time ./opentest01 /mnt/rawhide/opentest/ real 0m58.994s user 0m0.721s sys 0m19.578s (60+46)/59 == 1.79661016949152542372 So ~80% improvement in that test -- nice! -- Jeff Layton <jeff.layton@xxxxxxxxxxxxxxx> -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
