Messages in this thread Patch in this message | | | From | Jiri Slaby <> | Subject | [PATCH 3.12 047/181] nfsd: don't try to reuse an expired DRC entry off the list | Date | Mon, 30 Jun 2014 13:51:08 +0200 |
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From: Jeff Layton <jlayton@redhat.com>
3.12-stable review patch. If anyone has any objections, please let me know.
===============
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 <jlayton@redhat.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com> Signed-off-by: Jiri Slaby <jslaby@suse.cz> --- 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 b6af150c96b8..f8f060ffbf4f 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; -- 2.0.0
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