Rather than keeping our own LRU list, convert the nfsd DRC code to use
the new list_lru routines.
Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
---
fs/nfsd/nfscache.c | 94 ++++++++++++++++++++++++++++++++++++++----------------
1 file changed, 66 insertions(+), 28 deletions(-)
diff --git a/fs/nfsd/nfscache.c b/fs/nfsd/nfscache.c
index f8f060f..7f5480f 100644
--- a/fs/nfsd/nfscache.c
+++ b/fs/nfsd/nfscache.c
@@ -13,6 +13,7 @@
#include <linux/highmem.h>
#include <linux/log2.h>
#include <linux/hash.h>
+#include <linux/list_lru.h>
#include <net/checksum.h>
#include "nfsd.h"
@@ -28,7 +29,7 @@
#define TARGET_BUCKET_SIZE 64
static struct hlist_head * cache_hash;
-static struct list_head lru_head;
+static struct list_lru lru_head;
static struct kmem_cache *drc_slab;
/* max number of entries allowed in the cache */
@@ -132,7 +133,7 @@ nfsd_reply_cache_alloc(void)
}
static void
-nfsd_reply_cache_free_locked(struct svc_cacherep *rp)
+__nfsd_reply_cache_free_locked(struct svc_cacherep *rp)
{
if (rp->c_type == RC_REPLBUFF && rp->c_replvec.iov_base) {
drc_mem_usage -= rp->c_replvec.iov_len;
@@ -140,13 +141,26 @@ nfsd_reply_cache_free_locked(struct svc_cacherep *rp)
}
if (!hlist_unhashed(&rp->c_hash))
hlist_del(&rp->c_hash);
- list_del(&rp->c_lru);
--num_drc_entries;
drc_mem_usage -= sizeof(*rp);
kmem_cache_free(drc_slab, rp);
}
static void
+nfsd_reply_cache_free_locked(struct svc_cacherep *rp)
+{
+ list_lru_del(&lru_head, &rp->c_lru);
+ __nfsd_reply_cache_free_locked(rp);
+}
+
+static void
+nfsd_reply_cache_free_isolate(struct svc_cacherep *rp)
+{
+ list_del(&rp->c_lru);
+ __nfsd_reply_cache_free_locked(rp);
+}
+
+static void
nfsd_reply_cache_free(struct svc_cacherep *rp)
{
spin_lock(&cache_lock);
@@ -156,50 +170,66 @@ nfsd_reply_cache_free(struct svc_cacherep *rp)
int nfsd_reply_cache_init(void)
{
+ int ret;
unsigned int hashsize;
- INIT_LIST_HEAD(&lru_head);
max_drc_entries = nfsd_cache_size_limit();
num_drc_entries = 0;
hashsize = nfsd_hashsize(max_drc_entries);
maskbits = ilog2(hashsize);
register_shrinker(&nfsd_reply_cache_shrinker);
+
+ ret = list_lru_init(&lru_head);
+ if (ret)
+ goto out_error;
+
+ ret = -ENOMEM;
drc_slab = kmem_cache_create("nfsd_drc", sizeof(struct svc_cacherep),
0, 0, NULL);
if (!drc_slab)
- goto out_nomem;
+ goto out_error;
cache_hash = kcalloc(hashsize, sizeof(struct hlist_head), GFP_KERNEL);
if (!cache_hash)
- goto out_nomem;
+ goto out_error;
return 0;
-out_nomem:
- printk(KERN_ERR "nfsd: failed to allocate reply cache\n");
+out_error:
+ printk(KERN_ERR "nfsd: failed to setup reply cache: %d\n", ret);
nfsd_reply_cache_shutdown();
- return -ENOMEM;
+ return ret;
}
-void nfsd_reply_cache_shutdown(void)
+static enum lru_status
+nfsd_purge_lru_entry(struct list_head *item, spinlock_t *lock, void *cb_arg)
{
- struct svc_cacherep *rp;
+ struct svc_cacherep *rp = list_entry(item, struct svc_cacherep, c_lru);
+ nfsd_reply_cache_free_locked(rp);
+ return LRU_REMOVED;
+}
+
+void nfsd_reply_cache_shutdown(void)
+{
unregister_shrinker(&nfsd_reply_cache_shrinker);
cancel_delayed_work_sync(&cache_cleaner);
- while (!list_empty(&lru_head)) {
- rp = list_entry(lru_head.next, struct svc_cacherep, c_lru);
- nfsd_reply_cache_free_locked(rp);
- }
+ /* In principle, nothing should be altering the list now, but... */
+ spin_lock(&cache_lock);
+ list_lru_walk(&lru_head, nfsd_purge_lru_entry, NULL, ULONG_MAX);
+ spin_unlock(&cache_lock);
- kfree (cache_hash);
+ kfree(cache_hash);
cache_hash = NULL;
if (drc_slab) {
kmem_cache_destroy(drc_slab);
drc_slab = NULL;
}
+
+ list_lru_destroy(&lru_head);
+ memset(&lru_head, 0, sizeof(lru_head));
}
/*
@@ -210,7 +240,8 @@ static void
lru_put_end(struct svc_cacherep *rp)
{
rp->c_timestamp = jiffies;
- list_move_tail(&rp->c_lru, &lru_head);
+ list_lru_del(&lru_head, &rp->c_lru);
+ list_lru_add(&lru_head, &rp->c_lru);
schedule_delayed_work(&cache_cleaner, RC_EXPIRE);
}
@@ -231,23 +262,30 @@ nfsd_cache_entry_expired(struct svc_cacherep *rp)
time_after(jiffies, rp->c_timestamp + RC_EXPIRE);
}
+static enum lru_status
+nfsd_purge_expired_entry(struct list_head *item, spinlock_t *lock, void *cb_arg)
+{
+ struct svc_cacherep *rp = list_entry(item, struct svc_cacherep, c_lru);
+
+ if (!nfsd_cache_entry_expired(rp) &&
+ num_drc_entries <= max_drc_entries)
+ return LRU_SKIP_REST;
+
+ nfsd_reply_cache_free_isolate(rp);
+ return LRU_REMOVED;
+}
+
/*
* Walk the LRU list and prune off entries that are older than RC_EXPIRE.
* Also prune the oldest ones when the total exceeds the max number of entries.
*/
-static long
+static unsigned long
prune_cache_entries(void)
{
- struct svc_cacherep *rp, *tmp;
- long freed = 0;
+ unsigned long freed;
- list_for_each_entry_safe(rp, tmp, &lru_head, c_lru) {
- if (!nfsd_cache_entry_expired(rp) &&
- num_drc_entries <= max_drc_entries)
- break;
- nfsd_reply_cache_free_locked(rp);
- freed++;
- }
+ freed = list_lru_walk(&lru_head, nfsd_purge_expired_entry, NULL,
+ ULONG_MAX);
/*
* Conditionally rearm the job. If we cleaned out the list, then
@@ -255,7 +293,7 @@ prune_cache_entries(void)
* Otherwise, we rearm the job or modify the existing one to run in
* RC_EXPIRE since we just ran the pruner.
*/
- if (list_empty(&lru_head))
+ if (num_drc_entries == 0)
cancel_delayed_work(&cache_cleaner);
else
mod_delayed_work(system_wq, &cache_cleaner, RC_EXPIRE);
--
1.8.4.2
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