Return-Path: Received: from mx2.suse.de ([195.135.220.15]:38152 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752041AbbG2CTt (ORCPT ); Tue, 28 Jul 2015 22:19:49 -0400 Date: Wed, 29 Jul 2015 12:19:39 +1000 From: NeilBrown To: Kinglong Mee Cc: "J. Bruce Fields" , Al Viro , "linux-nfs@vger.kernel.org" , linux-fsdevel@vger.kernel.org, Trond Myklebust Subject: Re: [PATCH 7/9 v8] sunrpc: Switch to using hash list instead single list Message-ID: <20150729121939.517008f4@noble> In-Reply-To: <55B5A117.1020902@gmail.com> References: <55B5A012.1030006@gmail.com> <55B5A117.1020902@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: linux-nfs-owner@vger.kernel.org List-ID: On Mon, 27 Jul 2015 11:10:15 +0800 Kinglong Mee wrote: > Switch using list_head for cache_head in cache_detail, > it is useful of remove an cache_head entry directly from cache_detail. > > v8, using hash list, not head list > > Signed-off-by: Kinglong Mee Reviewed-by: NeilBrown Thanks, NeilBrown > --- > include/linux/sunrpc/cache.h | 4 +-- > net/sunrpc/cache.c | 60 +++++++++++++++++++++++--------------------- > 2 files changed, 33 insertions(+), 31 deletions(-) > > diff --git a/include/linux/sunrpc/cache.h b/include/linux/sunrpc/cache.h > index 04ee5a2..03d3b4c 100644 > --- a/include/linux/sunrpc/cache.h > +++ b/include/linux/sunrpc/cache.h > @@ -46,7 +46,7 @@ > * > */ > struct cache_head { > - struct cache_head * next; > + struct hlist_node cache_list; > time_t expiry_time; /* After time time, don't use the data */ > time_t last_refresh; /* If CACHE_PENDING, this is when upcall > * was sent, else this is when update was received > @@ -73,7 +73,7 @@ struct cache_detail_pipefs { > struct cache_detail { > struct module * owner; > int hash_size; > - struct cache_head ** hash_table; > + struct hlist_head * hash_table; > rwlock_t hash_lock; > > atomic_t inuse; /* active user-space update or lookup */ > diff --git a/net/sunrpc/cache.c b/net/sunrpc/cache.c > index 673c2fa..4a2340a 100644 > --- a/net/sunrpc/cache.c > +++ b/net/sunrpc/cache.c > @@ -44,7 +44,7 @@ static void cache_revisit_request(struct cache_head *item); > static void cache_init(struct cache_head *h) > { > time_t now = seconds_since_boot(); > - h->next = NULL; > + INIT_HLIST_NODE(&h->cache_list); > h->flags = 0; > kref_init(&h->ref); > h->expiry_time = now + CACHE_NEW_EXPIRY; > @@ -54,15 +54,14 @@ static void cache_init(struct cache_head *h) > struct cache_head *sunrpc_cache_lookup(struct cache_detail *detail, > struct cache_head *key, int hash) > { > - struct cache_head **head, **hp; > - struct cache_head *new = NULL, *freeme = NULL; > + struct cache_head *new = NULL, *freeme = NULL, *tmp = NULL; > + struct hlist_head *head; > > head = &detail->hash_table[hash]; > > read_lock(&detail->hash_lock); > > - for (hp=head; *hp != NULL ; hp = &(*hp)->next) { > - struct cache_head *tmp = *hp; > + hlist_for_each_entry(tmp, head, cache_list) { > if (detail->match(tmp, key)) { > if (cache_is_expired(detail, tmp)) > /* This entry is expired, we will discard it. */ > @@ -88,12 +87,10 @@ struct cache_head *sunrpc_cache_lookup(struct cache_detail *detail, > write_lock(&detail->hash_lock); > > /* check if entry appeared while we slept */ > - for (hp=head; *hp != NULL ; hp = &(*hp)->next) { > - struct cache_head *tmp = *hp; > + hlist_for_each_entry(tmp, head, cache_list) { > if (detail->match(tmp, key)) { > if (cache_is_expired(detail, tmp)) { > - *hp = tmp->next; > - tmp->next = NULL; > + hlist_del_init(&tmp->cache_list); > detail->entries --; > freeme = tmp; > break; > @@ -104,8 +101,8 @@ struct cache_head *sunrpc_cache_lookup(struct cache_detail *detail, > return tmp; > } > } > - new->next = *head; > - *head = new; > + > + hlist_add_head(&new->cache_list, head); > detail->entries++; > cache_get(new); > write_unlock(&detail->hash_lock); > @@ -143,7 +140,6 @@ struct cache_head *sunrpc_cache_update(struct cache_detail *detail, > * If 'old' is not VALID, we update it directly, > * otherwise we need to replace it > */ > - struct cache_head **head; > struct cache_head *tmp; > > if (!test_bit(CACHE_VALID, &old->flags)) { > @@ -168,15 +164,13 @@ struct cache_head *sunrpc_cache_update(struct cache_detail *detail, > } > cache_init(tmp); > detail->init(tmp, old); > - head = &detail->hash_table[hash]; > > write_lock(&detail->hash_lock); > if (test_bit(CACHE_NEGATIVE, &new->flags)) > set_bit(CACHE_NEGATIVE, &tmp->flags); > else > detail->update(tmp, new); > - tmp->next = *head; > - *head = tmp; > + hlist_add_head(&tmp->cache_list, &detail->hash_table[hash]); > detail->entries++; > cache_get(tmp); > cache_fresh_locked(tmp, new->expiry_time); > @@ -416,28 +410,29 @@ static int cache_clean(void) > /* find a non-empty bucket in the table */ > while (current_detail && > current_index < current_detail->hash_size && > - current_detail->hash_table[current_index] == NULL) > + hlist_empty(¤t_detail->hash_table[current_index])) > current_index++; > > /* find a cleanable entry in the bucket and clean it, or set to next bucket */ > > if (current_detail && current_index < current_detail->hash_size) { > - struct cache_head *ch, **cp; > + struct cache_head *ch = NULL; > struct cache_detail *d; > + struct hlist_head *head; > + struct hlist_node *tmp; > > write_lock(¤t_detail->hash_lock); > > /* Ok, now to clean this strand */ > > - cp = & current_detail->hash_table[current_index]; > - for (ch = *cp ; ch ; cp = & ch->next, ch = *cp) { > + head = ¤t_detail->hash_table[current_index]; > + hlist_for_each_entry_safe(ch, tmp, head, cache_list) { > if (current_detail->nextcheck > ch->expiry_time) > current_detail->nextcheck = ch->expiry_time+1; > if (!cache_is_expired(current_detail, ch)) > continue; > > - *cp = ch->next; > - ch->next = NULL; > + hlist_del_init(&ch->cache_list); > current_detail->entries--; > rv = 1; > break; > @@ -1284,7 +1279,7 @@ void *cache_seq_start(struct seq_file *m, loff_t *pos) > hash = n >> 32; > entry = n & ((1LL<<32) - 1); > > - for (ch=cd->hash_table[hash]; ch; ch=ch->next) > + hlist_for_each_entry(ch, &cd->hash_table[hash], cache_list) > if (!entry--) > return ch; > n &= ~((1LL<<32) - 1); > @@ -1292,11 +1287,12 @@ void *cache_seq_start(struct seq_file *m, loff_t *pos) > hash++; > n += 1LL<<32; > } while(hash < cd->hash_size && > - cd->hash_table[hash]==NULL); > + hlist_empty(&cd->hash_table[hash])); > if (hash >= cd->hash_size) > return NULL; > *pos = n+1; > - return cd->hash_table[hash]; > + return hlist_entry_safe(cd->hash_table[hash].first, > + struct cache_head, cache_list); > } > EXPORT_SYMBOL_GPL(cache_seq_start); > > @@ -1308,23 +1304,25 @@ void *cache_seq_next(struct seq_file *m, void *p, loff_t *pos) > > if (p == SEQ_START_TOKEN) > hash = 0; > - else if (ch->next == NULL) { > + else if (ch->cache_list.next == NULL) { > hash++; > *pos += 1LL<<32; > } else { > ++*pos; > - return ch->next; > + return hlist_entry_safe(ch->cache_list.next, > + struct cache_head, cache_list); > } > *pos &= ~((1LL<<32) - 1); > while (hash < cd->hash_size && > - cd->hash_table[hash] == NULL) { > + hlist_empty(&cd->hash_table[hash])) { > hash++; > *pos += 1LL<<32; > } > if (hash >= cd->hash_size) > return NULL; > ++*pos; > - return cd->hash_table[hash]; > + return hlist_entry_safe(cd->hash_table[hash].first, > + struct cache_head, cache_list); > } > EXPORT_SYMBOL_GPL(cache_seq_next); > > @@ -1666,17 +1664,21 @@ EXPORT_SYMBOL_GPL(cache_unregister_net); > struct cache_detail *cache_create_net(struct cache_detail *tmpl, struct net *net) > { > struct cache_detail *cd; > + int i; > > cd = kmemdup(tmpl, sizeof(struct cache_detail), GFP_KERNEL); > if (cd == NULL) > return ERR_PTR(-ENOMEM); > > - cd->hash_table = kzalloc(cd->hash_size * sizeof(struct cache_head *), > + cd->hash_table = kzalloc(cd->hash_size * sizeof(struct hlist_head), > GFP_KERNEL); > if (cd->hash_table == NULL) { > kfree(cd); > return ERR_PTR(-ENOMEM); > } > + > + for (i = 0; i < cd->hash_size; i++) > + INIT_HLIST_HEAD(&cd->hash_table[i]); > cd->net = net; > return cd; > }