From: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx> If we're only opening the file for reading, and the file is empty and/or we already have cached data, then heuristically optimise away the LAYOUTGET. Signed-off-by: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx> --- fs/nfs/pnfs.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c index 8c6ce63f5ed0..5fc4d84d9326 100644 --- a/fs/nfs/pnfs.c +++ b/fs/nfs/pnfs.c @@ -1996,6 +1996,11 @@ static void _lgopen_prepare_attached(struct nfs4_opendata *data, struct nfs4_layoutget *lgp; struct pnfs_layout_hdr *lo; + /* Heuristic: don't send layoutget if we have cached data */ + if (rng.iomode == IOMODE_READ && + (i_size_read(ino) == 0 || ino->i_mapping->nrpages != 0)) + return; + lo = _pnfs_grab_empty_layout(ino, ctx); if (!lo) return; -- 2.17.0 -- 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
