From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934012AbaLBTdO (ORCPT ); Tue, 2 Dec 2014 14:33:14 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:46985 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933730AbaLBT0p (ORCPT ); Tue, 2 Dec 2014 14:26:45 -0500 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Jeff Layton , "J. Bruce Fields" , Joseph Salisbury , Kamal Mostafa Subject: [PATCH 3.13.y-ckt 043/121] nfsd: don't try to reuse an expired DRC entry off the list Date: Tue, 2 Dec 2014 11:18:42 -0800 Message-Id: <1417548000-1794-44-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1417548000-1794-1-git-send-email-kamal@canonical.com> References: <1417548000-1794-1-git-send-email-kamal@canonical.com> X-Extended-Stable: 3.13 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.13.11-ckt12 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Jeff Layton commit a0ef5e19684f0447da9ff0654a12019c484f57ca upstream. Currently when we are processing a request, we try to scrape an expired or over-limit entry off the list in preference to allocating a new one from the slab. This is unnecessarily complicated. Just use the slab layer. Signed-off-by: Jeff Layton Signed-off-by: J. Bruce Fields Cc: Joseph Salisbury Reference: http://bugs.launchpad.net/bugs/1396065 Signed-off-by: Kamal Mostafa --- fs/nfsd/nfscache.c | 36 ++++-------------------------------- 1 file changed, 4 insertions(+), 32 deletions(-) diff --git a/fs/nfsd/nfscache.c b/fs/nfsd/nfscache.c index b6af150..f8f060f 100644 --- a/fs/nfsd/nfscache.c +++ b/fs/nfsd/nfscache.c @@ -132,13 +132,6 @@ nfsd_reply_cache_alloc(void) } static void -nfsd_reply_cache_unhash(struct svc_cacherep *rp) -{ - hlist_del_init(&rp->c_hash); - list_del_init(&rp->c_lru); -} - -static void nfsd_reply_cache_free_locked(struct svc_cacherep *rp) { if (rp->c_type == RC_REPLBUFF && rp->c_replvec.iov_base) { @@ -416,22 +409,8 @@ nfsd_cache_lookup(struct svc_rqst *rqstp) /* * Since the common case is a cache miss followed by an insert, - * preallocate an entry. First, try to reuse the first entry on the LRU - * if it works, then go ahead and prune the LRU list. + * preallocate an entry. */ - spin_lock(&cache_lock); - if (!list_empty(&lru_head)) { - rp = list_first_entry(&lru_head, struct svc_cacherep, c_lru); - if (nfsd_cache_entry_expired(rp) || - num_drc_entries >= max_drc_entries) { - nfsd_reply_cache_unhash(rp); - prune_cache_entries(); - goto search_cache; - } - } - - /* No expired ones available, allocate a new one. */ - spin_unlock(&cache_lock); rp = nfsd_reply_cache_alloc(); spin_lock(&cache_lock); if (likely(rp)) { @@ -439,7 +418,9 @@ nfsd_cache_lookup(struct svc_rqst *rqstp) drc_mem_usage += sizeof(*rp); } -search_cache: + /* go ahead and prune the cache */ + prune_cache_entries(); + found = nfsd_cache_search(rqstp, csum); if (found) { if (likely(rp)) @@ -453,15 +434,6 @@ search_cache: goto out; } - /* - * We're keeping the one we just allocated. Are we now over the - * limit? Prune one off the tip of the LRU in trade for the one we - * just allocated if so. - */ - if (num_drc_entries >= max_drc_entries) - nfsd_reply_cache_free_locked(list_first_entry(&lru_head, - struct svc_cacherep, c_lru)); - nfsdstats.rcmisses++; rqstp->rq_cacherep = rp; rp->c_state = RC_INPROG; -- 1.9.1