Return-Path: Received: from mail-io0-f194.google.com ([209.85.223.194]:42175 "EHLO mail-io0-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751135AbeC1QSb (ORCPT ); Wed, 28 Mar 2018 12:18:31 -0400 Received: by mail-io0-f194.google.com with SMTP id d5so4189300iob.9 for ; Wed, 28 Mar 2018 09:18:31 -0700 (PDT) From: Trond Myklebust To: "J . Bruce Fields" Cc: linux-nfs@vger.kernel.org Subject: [PATCH] nfsd: Do not refuse to serve out of cache Date: Wed, 28 Mar 2018 12:18:01 -0400 Message-Id: <20180328161801.8360-1-trond.myklebust@primarydata.com> MIME-Version: 1.0 Sender: linux-nfs-owner@vger.kernel.org List-ID: Currently the knfsd replay cache appears to try to refuse replying to retries that come within 200ms of the cache entry being created. That makes limited sense in today's world of high speed TCP. Signed-off-by: Trond Myklebust --- fs/nfsd/cache.h | 5 ----- fs/nfsd/nfscache.c | 6 ++---- 2 files changed, 2 insertions(+), 9 deletions(-) diff --git a/fs/nfsd/cache.h b/fs/nfsd/cache.h index 046b3f048757..b7559c6f2b97 100644 --- a/fs/nfsd/cache.h +++ b/fs/nfsd/cache.h @@ -67,11 +67,6 @@ enum { RC_REPLBUFF, }; -/* - * If requests are retransmitted within this interval, they're dropped. - */ -#define RC_DELAY (HZ/5) - /* Cache entries expire after this time period */ #define RC_EXPIRE (120 * HZ) diff --git a/fs/nfsd/nfscache.c b/fs/nfsd/nfscache.c index 334f2ad60704..637f87c39183 100644 --- a/fs/nfsd/nfscache.c +++ b/fs/nfsd/nfscache.c @@ -394,7 +394,6 @@ nfsd_cache_lookup(struct svc_rqst *rqstp) __wsum csum; u32 hash = nfsd_cache_hash(xid); struct nfsd_drc_bucket *b = &drc_hashtbl[hash]; - unsigned long age; int type = rqstp->rq_cachetype; int rtn = RC_DOIT; @@ -461,12 +460,11 @@ nfsd_cache_lookup(struct svc_rqst *rqstp) found_entry: nfsdstats.rchits++; /* We found a matching entry which is either in progress or done. */ - age = jiffies - rp->c_timestamp; lru_put_end(b, rp); rtn = RC_DROPIT; - /* Request being processed or excessive rexmits */ - if (rp->c_state == RC_INPROG || age < RC_DELAY) + /* Request being processed */ + if (rp->c_state == RC_INPROG) goto out; /* From the hall of fame of impractical attacks: -- 2.14.3