On Fri, 2012-04-20 at 14:47 -0400, Fred Isaman wrote:
> The coalesce code made assumptions that will no longer be true once
> non-page aligned io occurs. This introduces no change in
> current behavior, but allows for more general situations to come.
>
> Signed-off-by: Fred Isaman <iisaman@xxxxxxxxxx>
> ---
> fs/nfs/nfs4filelayout.c | 12 ++++++++++++
> fs/nfs/pagelist.c | 2 +-
> fs/nfs/pnfs.c | 8 ++++++++
> 3 files changed, 21 insertions(+), 1 deletions(-)
>
> diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c
> index 5d01a16..b344946 100644
> --- a/fs/nfs/pagelist.c
> +++ b/fs/nfs/pagelist.c
> @@ -280,7 +280,7 @@ static bool nfs_can_coalesce_requests(struct nfs_page *prev,
> return false;
> if (req->wb_context->state != prev->wb_context->state)
> return false;
> - if (req->wb_index != (prev->wb_index + 1))
> + if (req_offset(req) != req_offset(prev) + prev->wb_bytes)
Can we micro-optimise this just a teensy bit by moving it until after
the req->wb_base and prev->wb_base tests? Since those are
computationally simpler, doing them first might make the "can't
coalesce" test a little faster.
> return false;
> if (req->wb_pgbase != 0)
> return false;
--
Trond Myklebust
Linux NFS client maintainer
NetApp
Trond.Myklebust@xxxxxxxxxx
www.netapp.com
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