nfsd: Reduce the number of calls to nfsd_file_gc()

Don't call nfsd_file_gc() on every put of the reference in nfsd_file_put().
Instead, do it only when we're expecting the refcount to go to 1.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

diff --git a/fs/nfsd/filecache.c b/fs/nfsd/filecache.c
index 4cef03a..9c2b29e 100644 (file)
--- a/fs/nfsd/filecache.c
+++ b/fs/nfsd/filecache.c
@@ -282,27 +282,32 @@ nfsd_file_unhash_and_release_locked(struct nfsd_file *nf, struct list_head *disp
        return true;
 }
 
-static int
+static void
 nfsd_file_put_noref(struct nfsd_file *nf)
 {
-       int count;
        trace_nfsd_file_put(nf);
 
-       count = atomic_dec_return(&nf->nf_ref);
-       if (!count) {
+       if (atomic_dec_and_test(&nf->nf_ref)) {
                WARN_ON(test_bit(NFSD_FILE_HASHED, &nf->nf_flags));
                nfsd_file_free(nf);
        }
-       return count;
 }
 
 void
 nfsd_file_put(struct nfsd_file *nf)
 {
-       bool is_hashed = test_bit(NFSD_FILE_HASHED, &nf->nf_flags) != 0;
+       bool is_hashed;
 
        set_bit(NFSD_FILE_REFERENCED, &nf->nf_flags);
-       if (nfsd_file_put_noref(nf) == 1 && is_hashed)
+       if (atomic_read(&nf->nf_ref) > 2 || !nf->nf_file) {
+               nfsd_file_put_noref(nf);
+               return;
+       }
+
+       filemap_flush(nf->nf_file->f_mapping);
+       is_hashed = test_bit(NFSD_FILE_HASHED, &nf->nf_flags) != 0;
+       nfsd_file_put_noref(nf);
+       if (is_hashed)
                nfsd_file_schedule_laundrette();
        if (atomic_long_read(&nfsd_filecache_count) >= NFSD_FILE_LRU_LIMIT)
                nfsd_file_gc();