[PATCH] NFS: Replace nfs_page insertion sort with a radix sort

 Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

3 files changed, 89 insertions, 70 deletions

diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index 4f545f382ba6..4845911f1c63 100644
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -135,7 +135,7 @@ nfs_write_inode(struct inode *inode, int sync)
         int flags = sync ? FLUSH_WAIT : 0;
         int ret;
 
-        ret = nfs_commit_inode(inode, 0, 0, flags);
+        ret = nfs_commit_inode(inode, flags);
         if (ret < 0)
                 return ret;
         return 0;
diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c
index 356a33bb38a6..d53857b148e2 100644
--- a/fs/nfs/pagelist.c
+++ b/fs/nfs/pagelist.c
@@ -177,36 +177,6 @@ nfs_release_request(struct nfs_page *req)
         nfs_page_free(req);
 }
 
-/**
- * nfs_list_add_request - Insert a request into a sorted list
- * @req: request
- * @head: head of list into which to insert the request.
- *
- * Note that the wb_list is sorted by page index in order to facilitate
- * coalescing of requests.
- * We use an insertion sort that is optimized for the case of appended
- * writes.
- */
-void
-nfs_list_add_request(struct nfs_page *req, struct list_head *head)
-{
-        struct list_head *pos;
-
-#ifdef NFS_PARANOIA
-        if (!list_empty(&req->wb_list)) {
-                printk(KERN_ERR "NFS: Add to list failed!\n");
-                BUG();
-        }
-#endif
-        list_for_each_prev(pos, head) {
-                struct nfs_page *p = nfs_list_entry(pos);
-                if (p->wb_index < req->wb_index)
-                        break;
-        }
-        list_add(&req->wb_list, pos);
-        req->wb_list_head = head;
-}
-
 static int nfs_wait_bit_interruptible(void *word)
 {
         int ret = 0;
@@ -291,6 +261,62 @@ nfs_coalesce_requests(struct list_head *head, struct list_head *dst,
         return npages;
 }
 
+#define NFS_SCAN_MAXENTRIES 16
+/**
+ * nfs_scan_lock_dirty - Scan the radix tree for dirty requests
+ * @nfsi: NFS inode
+ * @dst: Destination list
+ * @idx_start: lower bound of page->index to scan
+ * @npages: idx_start + npages sets the upper bound to scan.
+ *
+ * Moves elements from one of the inode request lists.
+ * If the number of requests is set to 0, the entire address_space
+ * starting at index idx_start, is scanned.
+ * The requests are *not* checked to ensure that they form a contiguous set.
+ * You must be holding the inode's req_lock when calling this function
+ */
+int
+nfs_scan_lock_dirty(struct nfs_inode *nfsi, struct list_head *dst,
+              unsigned long idx_start, unsigned int npages)
+{
+        struct nfs_page *pgvec[NFS_SCAN_MAXENTRIES];
+        struct nfs_page *req;
+        unsigned long idx_end;
+        int found, i;
+        int res;
+
+        res = 0;
+        if (npages == 0)
+                idx_end = ~0;
+        else
+                idx_end = idx_start + npages - 1;
+
+        for (;;) {
+                found = radix_tree_gang_lookup_tag(&nfsi->nfs_page_tree,
+                                (void **)&pgvec[0], idx_start, NFS_SCAN_MAXENTRIES,
+                                NFS_PAGE_TAG_DIRTY);
+                if (found <= 0)
+                        break;
+                for (i = 0; i < found; i++) {
+                        req = pgvec[i];
+                        if (req->wb_index > idx_end)
+                                goto out;
+
+                        idx_start = req->wb_index + 1;
+
+                        if (nfs_set_page_writeback_locked(req)) {
+                                radix_tree_tag_clear(&nfsi->nfs_page_tree,
+                                                req->wb_index, NFS_PAGE_TAG_DIRTY);
+                                nfs_list_remove_request(req);
+                                nfs_list_add_request(req, dst);
+                                res++;
+                        }
+                }
+        }
+out:
+        return res;
+}
+
 /**
  * nfs_scan_list - Scan a list for matching requests
  * @head: One of the NFS inode request lists
diff --git a/fs/nfs/write.c b/fs/nfs/write.c
index 58a39b0486a7..5130eda231d7 100644
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -352,7 +352,7 @@ int nfs_writepages(struct address_space *mapping, struct writeback_control *wbc)
                 if (err < 0)
                         goto out;
         }
-        err = nfs_commit_inode(inode, 0, 0, wb_priority(wbc));
+        err = nfs_commit_inode(inode, wb_priority(wbc));
         if (err > 0) {
                 wbc->nr_to_write -= err;
                 err = 0;
@@ -446,6 +446,8 @@ nfs_mark_request_dirty(struct nfs_page *req)
         struct nfs_inode *nfsi = NFS_I(inode);
 
         spin_lock(&nfsi->req_lock);
+        radix_tree_tag_set(&nfsi->nfs_page_tree,
+                        req->wb_index, NFS_PAGE_TAG_DIRTY);
         nfs_list_add_request(req, &nfsi->dirty);
         nfsi->ndirty++;
         spin_unlock(&nfsi->req_lock);
@@ -537,12 +539,15 @@ static int
 nfs_scan_dirty(struct inode *inode, struct list_head *dst, unsigned long idx_start, unsigned int npages)
 {
         struct nfs_inode *nfsi = NFS_I(inode);
-        int     res;
-        res = nfs_scan_list(&nfsi->dirty, dst, idx_start, npages);
-        nfsi->ndirty -= res;
-        sub_page_state(nr_dirty,res);
-        if ((nfsi->ndirty == 0) != list_empty(&nfsi->dirty))
-                printk(KERN_ERR "NFS: desynchronized value of nfs_i.ndirty.\n");
+        int res = 0;
+
+        if (nfsi->ndirty != 0) {
+                res = nfs_scan_lock_dirty(nfsi, dst, idx_start, npages);
+                nfsi->ndirty -= res;
+                sub_page_state(nr_dirty,res);
+                if ((nfsi->ndirty == 0) != list_empty(&nfsi->dirty))
+                        printk(KERN_ERR "NFS: desynchronized value of nfs_i.ndirty.\n");
+        }
         return res;
 }
 
@@ -561,11 +566,14 @@ static int
 nfs_scan_commit(struct inode *inode, struct list_head *dst, unsigned long idx_start, unsigned int npages)
 {
         struct nfs_inode *nfsi = NFS_I(inode);
-        int     res;
-        res = nfs_scan_list(&nfsi->commit, dst, idx_start, npages);
-        nfsi->ncommit -= res;
-        if ((nfsi->ncommit == 0) != list_empty(&nfsi->commit))
-                printk(KERN_ERR "NFS: desynchronized value of nfs_i.ncommit.\n");
+        int res = 0;
+
+        if (nfsi->ncommit != 0) {
+                res = nfs_scan_list(&nfsi->commit, dst, idx_start, npages);
+                nfsi->ncommit -= res;
+                if ((nfsi->ncommit == 0) != list_empty(&nfsi->commit))
+                        printk(KERN_ERR "NFS: desynchronized value of nfs_i.ncommit.\n");
+        }
         return res;
 }
 #endif
@@ -1209,36 +1217,24 @@ static void nfs_commit_rpcsetup(struct list_head *head,
                 struct nfs_write_data *data, int how)
 {
         struct rpc_task         *task = &data->task;
-        struct nfs_page         *first, *last;
+        struct nfs_page         *first;
         struct inode            *inode;
-        loff_t                  start, end, len;
 
         /* Set up the RPC argument and reply structs
          * NB: take care not to mess about with data->commit et al. */
 
         list_splice_init(head, &data->pages);
         first = nfs_list_entry(data->pages.next);
-        last = nfs_list_entry(data->pages.prev);
         inode = first->wb_context->dentry->d_inode;
 
-        /*
-         * Determine the offset range of requests in the COMMIT call.
-         * We rely on the fact that data->pages is an ordered list...
-         */
-        start = req_offset(first);
-        end = req_offset(last) + last->wb_bytes;
-        len = end - start;
-        /* If 'len' is not a 32-bit quantity, pass '0' in the COMMIT call */
-        if (end >= i_size_read(inode) || len < 0 || len > (~((u32)0) >> 1))
-                len = 0;
-
         data->inode       = inode;
         data->cred        = first->wb_context->cred;
 
         data->args.fh     = NFS_FH(data->inode);
-        data->args.offset = start;
-        data->args.count  = len;
-        data->res.count   = len;
+        /* Note: we always request a commit of the entire inode */
+        data->args.offset = 0;
+        data->args.count  = 0;
+        data->res.count   = 0;
         data->res.fattr   = &data->fattr;
         data->res.verf    = &data->verf;
         
@@ -1357,8 +1353,7 @@ static int nfs_flush_inode(struct inode *inode, unsigned long idx_start,
 }
 
 #if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
-int nfs_commit_inode(struct inode *inode, unsigned long idx_start,
-                    unsigned int npages, int how)
+int nfs_commit_inode(struct inode *inode, int how)
 {
         struct nfs_inode *nfsi = NFS_I(inode);
         LIST_HEAD(head);
@@ -1366,15 +1361,13 @@ int nfs_commit_inode(struct inode *inode, unsigned long idx_start,
                                 error = 0;
 
         spin_lock(&nfsi->req_lock);
-        res = nfs_scan_commit(inode, &head, idx_start, npages);
+        res = nfs_scan_commit(inode, &head, 0, 0);
+        spin_unlock(&nfsi->req_lock);
         if (res) {
-                res += nfs_scan_commit(inode, &head, 0, 0);
-                spin_unlock(&nfsi->req_lock);
                 error = nfs_commit_list(&head, how);
-        } else
-                spin_unlock(&nfsi->req_lock);
-        if (error < 0)
-                return error;
+                if (error < 0)
+                        return error;
+        }
         return res;
 }
 #endif
@@ -1396,7 +1389,7 @@ int nfs_sync_inode(struct inode *inode, unsigned long idx_start,
                         error = nfs_flush_inode(inode, idx_start, npages, how);
 #if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
                 if (error == 0)
-                        error = nfs_commit_inode(inode, idx_start, npages, how);
+                        error = nfs_commit_inode(inode, how);
 #endif
         } while (error > 0);
         return error;