NFSD: Batch release pages during splice read

Large splice reads call put_page() repeatedly. put_page() is
relatively expensive to call, so replace it with the new
svc_rqst_replace_page() helper to help amortize that cost.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: NeilBrown <neilb@suse.de>

diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index 46a6d9fce3d26b34dfb99ce2affd41677897be02..7732a384f949680fc359cfe387661df32311f85a 100644 (file)
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -849,15 +849,10 @@ nfsd_splice_actor(struct pipe_inode_info *pipe, struct pipe_buffer *buf,
        struct page *page = buf->page;
 
        if (rqstp->rq_res.page_len == 0) {
-               get_page(page);
-               put_page(*rqstp->rq_next_page);
-               *(rqstp->rq_next_page++) = page;
+               svc_rqst_replace_page(rqstp, page);
                rqstp->rq_res.page_base = buf->offset;
        } else if (page != pp[-1]) {
-               get_page(page);
-               if (*rqstp->rq_next_page)
-                       put_page(*rqstp->rq_next_page);
-               *(rqstp->rq_next_page++) = page;
+               svc_rqst_replace_page(rqstp, page);
        }
        rqstp->rq_res.page_len += sd->len;