diff options
| -rw-r--r-- | fs/nfsd/filecache.c | 27 | ||||
| -rw-r--r-- | fs/nfsd/filecache.h | 6 |
2 files changed, 30 insertions, 3 deletions
diff --git a/fs/nfsd/filecache.c b/fs/nfsd/filecache.c index 2289065ee5e8..ab85e6a2454f 100644 --- a/fs/nfsd/filecache.c +++ b/fs/nfsd/filecache.c @@ -544,6 +544,13 @@ nfsd_file_gc_cb(struct list_head *item, struct list_lru_one *lru, return nfsd_file_lru_cb(item, lru, arg); } +/* If the shrinker runs between calls to list_lru_walk_node() in + * nfsd_file_gc(), the "remaining" count will be wrong. This could + * result in premature freeing of some files. This may not matter much + * but is easy to fix with this spinlock which temporarily disables + * the shrinker. + */ +static DEFINE_SPINLOCK(nfsd_gc_lock); static void nfsd_file_gc(void) { @@ -551,12 +558,22 @@ nfsd_file_gc(void) LIST_HEAD(dispose); int nid; + spin_lock(&nfsd_gc_lock); for_each_node_state(nid, N_NORMAL_MEMORY) { - unsigned long nr = list_lru_count_node(&nfsd_file_lru, nid); + unsigned long remaining = list_lru_count_node(&nfsd_file_lru, nid); + + while (remaining > 0) { + unsigned long nr = min(remaining, NFSD_FILE_GC_BATCH); - ret += list_lru_walk_node(&nfsd_file_lru, nid, nfsd_file_gc_cb, - &dispose, &nr); + remaining -= nr; + ret += list_lru_walk_node(&nfsd_file_lru, nid, nfsd_file_gc_cb, + &dispose, &nr); + if (nr) + /* walk aborted early */ + remaining = 0; + } } + spin_unlock(&nfsd_gc_lock); trace_nfsd_file_gc_removed(ret, list_lru_count(&nfsd_file_lru)); nfsd_file_dispose_list_delayed(&dispose); } @@ -581,8 +598,12 @@ nfsd_file_lru_scan(struct shrinker *s, struct shrink_control *sc) LIST_HEAD(dispose); unsigned long ret; + if (!spin_trylock(&nfsd_gc_lock)) + return SHRINK_STOP; + ret = list_lru_shrink_walk(&nfsd_file_lru, sc, nfsd_file_lru_cb, &dispose); + spin_unlock(&nfsd_gc_lock); trace_nfsd_file_shrinker_removed(ret, list_lru_count(&nfsd_file_lru)); nfsd_file_dispose_list_delayed(&dispose); return ret; diff --git a/fs/nfsd/filecache.h b/fs/nfsd/filecache.h index de5b8aa7fcb0..5865f9c72712 100644 --- a/fs/nfsd/filecache.h +++ b/fs/nfsd/filecache.h @@ -4,6 +4,12 @@ #include <linux/fsnotify_backend.h> /* + * Limit the time that the list_lru_one lock is held during + * an LRU scan. + */ +#define NFSD_FILE_GC_BATCH (16UL) + +/* * This is the fsnotify_mark container that nfsd attaches to the files that it * is holding open. Note that we have a separate refcount here aside from the * one in the fsnotify_mark. We only want a single fsnotify_mark attached to |