Return-Path: linux-nfs-owner@vger.kernel.org Received: from mx2.netapp.com ([216.240.18.37]:34959 "EHLO mx2.netapp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760971Ab2ERBX6 (ORCPT ); Thu, 17 May 2012 21:23:58 -0400 From: andros@netapp.com To: trond.myklebust@netapp.com Cc: linux-nfs@vger.kernel.org, Andy Adamson Subject: [PATCH Version 9 4/4] NFSv4.1 test the mdsthreshold hint parameters Date: Thu, 17 May 2012 15:48:22 -0400 Message-Id: <1337284102-3372-4-git-send-email-andros@netapp.com> In-Reply-To: <1337284102-3372-1-git-send-email-andros@netapp.com> References: <1337284102-3372-1-git-send-email-andros@netapp.com> Sender: linux-nfs-owner@vger.kernel.org List-ID: From: Andy Adamson Signed-off-by: Andy Adamson --- fs/nfs/pnfs.c | 78 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 files changed, 78 insertions(+), 0 deletions(-) diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c index 924dce1..1db7416 100644 --- a/fs/nfs/pnfs.c +++ b/fs/nfs/pnfs.c @@ -934,6 +934,80 @@ 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 + * before each LAYOUTGET. 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 length is less than the value of threshold4 read or write size, + * then it is RECOMMENDED that the client read from the file via the MDS and + * not a storage device. + * + * For I/O sizes below the threshold4 read or write iosize, it is RECOMMENDED + * to access data through the MDS. + */ +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; + bool ret = false; + + if (t == NULL || t->bm == 0) + 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. */ @@ -960,6 +1034,10 @@ pnfs_update_layout(struct inode *ino, if (!pnfs_enabled_sb(NFS_SERVER(ino))) return NULL; + + if (pnfs_within_mdsthreshold(ctx, ino, iomode)) + return NULL; + spin_lock(&ino->i_lock); lo = pnfs_find_alloc_layout(ino, ctx, gfp_flags); if (lo == NULL) { -- 1.7.7.6