On 05/23/2012 12:02 PM, andros@xxxxxxxxxx wrote:
> From: Andy Adamson <andros@xxxxxxxxxx>
>
> Signed-off-by: Andy Adamson <andros@xxxxxxxxxx>
> ---
> fs/nfs/pnfs.c | 79 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> 1 files changed, 79 insertions(+), 0 deletions(-)
>
> diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
> index 6620606..b8323aa 100644
> --- a/fs/nfs/pnfs.c
> +++ b/fs/nfs/pnfs.c
> @@ -936,6 +936,81 @@ pnfs_find_lseg(struct pnfs_layout_hdr *lo,
> }
>
> /*
> + * Use mdsthreshold hints set at each OPEN to determine if I/O should go
> + * to the MDS or over pNFS
> + *
> + * The nfs_inode read_io and write_io fields are cumulative counters reset
> + * when there are no layout segments. Note that in pnfs_update_layout iomode
> + * is set to IOMODE_READ for a READ request, and set to IOMODE_RW for a
> + * WRITE request.
> + *
> + * A return of true means use MDS I/O.
> + *
> + * From rfc 5661:
> + * If a file's size is smaller than the file size threshold, data accesses
> + * SHOULD be sent to the metadata server. If an I/O request has a length that
> + * is below the I/O size threshold, the I/O SHOULD be sent to the metadata
> + * server. If both file size and I/O size are provided, the client SHOULD
> + * reach or exceed both thresholds before sending its read or write
> + * requests to the data server.
> + */
> +static bool pnfs_within_mdsthreshold(struct nfs_open_context *ctx,
> + struct inode *ino, int iomode)
> +{
> + struct nfs4_threshold *t = ctx->mdsthreshold;
> + struct nfs_inode *nfsi = NFS_I(ino);
> + loff_t fsize = i_size_read(ino);
> + bool size = false, size_set = false, io = false, io_set = false, ret = false;
> +
> + if (t == NULL)
> + return ret;
> +
> + dprintk("%s bm=0x%x rd_sz=%llu wr_sz=%llu rd_io=%llu wr_io=%llu\n",
> + __func__, t->bm, t->rd_sz, t->wr_sz, t->rd_io_sz, t->wr_io_sz);
> +
> + switch (iomode) {
> + case IOMODE_READ:
> + if (t->bm & THRESHOLD_RD) {
> + dprintk("%s fsize %llu\n", __func__, fsize);
> + size_set = true;
> + if (fsize < t->rd_sz)
> + size = true;
> + }
> + if (t->bm & THRESHOLD_RD_IO) {
> + dprintk("%s nfsi->read_io %llu\n", __func__,
> + nfsi->read_io);
> + io_set = true;
> + if (nfsi->read_io < t->rd_io_sz)
> + io = true;
> + }
> + break;
> + case IOMODE_RW:
> + if (t->bm & THRESHOLD_WR) {
> + dprintk("%s fsize %llu\n", __func__, fsize);
> + size_set = true;
> + if (fsize < t->wr_sz)
> + size = true;
> + }
> + if (t->bm & THRESHOLD_WR_IO) {
> + dprintk("%s nfsi->write_io %llu\n", __func__,
> + nfsi->write_io);
> + io_set = true;
> + if (nfsi->write_io < t->wr_io_sz)
> + io = true;
> + }
> + break;
> + }
> + if (size_set && io_set) {
> + if (size && io)
> + ret = true;
> + } else if (size || io)
> + ret = true;
> +
> + dprintk("<-- %s size %d io %d ret %d\n", __func__, size, io, ret);
> + return ret;
> +}
> +
> +/*
> * Layout segment is retreived from the server if not cached.
> * The appropriate layout segment is referenced and returned to the caller.
> */
> @@ -962,6 +1037,10 @@ pnfs_update_layout(struct inode *ino,
>
> if (!pnfs_enabled_sb(NFS_SERVER(ino)))
> return NULL;
> +
> + if (pnfs_within_mdsthreshold(ctx, ino, iomode))
> + return NULL;
> +
Would we want to use these counters as the recommended layout_size in
read and write, instead of current's PAGE_SIZE?
Boaz
> spin_lock(&ino->i_lock);
> lo = pnfs_find_alloc_layout(ino, ctx, gfp_flags);
> if (lo == NULL) {
--
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
