NFS: Add a count of the number of unstable writes carried by an inode
Trond Myklebust [Sat, 20 Feb 2010 00:53:39 +0000 (16:53 -0800)]
In order to know when we should do opportunistic commits of the unstable
writes, when the VM is doing a background flush, we add a field to count
the number of unstable writes.

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

fs/nfs/inode.c
fs/nfs/write.c
include/linux/nfs_fs.h

index 89e9831..aa5a831 100644 (file)
@@ -1404,6 +1404,7 @@ static void init_once(void *foo)
        INIT_LIST_HEAD(&nfsi->access_cache_inode_lru);
        INIT_RADIX_TREE(&nfsi->nfs_page_tree, GFP_ATOMIC);
        nfsi->npages = 0;
+       nfsi->ncommit = 0;
        atomic_set(&nfsi->silly_count, 1);
        INIT_HLIST_HEAD(&nfsi->silly_list);
        init_waitqueue_head(&nfsi->waitqueue);
index 09e9709..dc08a6f 100644 (file)
@@ -438,6 +438,7 @@ nfs_mark_request_commit(struct nfs_page *req)
        radix_tree_tag_set(&nfsi->nfs_page_tree,
                        req->wb_index,
                        NFS_PAGE_TAG_COMMIT);
+       nfsi->ncommit++;
        spin_unlock(&inode->i_lock);
        inc_zone_page_state(req->wb_page, NR_UNSTABLE_NFS);
        inc_bdi_stat(req->wb_page->mapping->backing_dev_info, BDI_RECLAIMABLE);
@@ -573,11 +574,15 @@ static int
 nfs_scan_commit(struct inode *inode, struct list_head *dst, pgoff_t idx_start, unsigned int npages)
 {
        struct nfs_inode *nfsi = NFS_I(inode);
+       int ret;
 
        if (!nfs_need_commit(nfsi))
                return 0;
 
-       return nfs_scan_list(nfsi, dst, idx_start, npages, NFS_PAGE_TAG_COMMIT);
+       ret = nfs_scan_list(nfsi, dst, idx_start, npages, NFS_PAGE_TAG_COMMIT);
+       if (ret > 0)
+               nfsi->ncommit -= ret;
+       return ret;
 }
 #else
 static inline int nfs_need_commit(struct nfs_inode *nfsi)
@@ -642,9 +647,10 @@ static struct nfs_page *nfs_try_to_update_request(struct inode *inode,
                spin_lock(&inode->i_lock);
        }
 
-       if (nfs_clear_request_commit(req))
-               radix_tree_tag_clear(&NFS_I(inode)->nfs_page_tree,
-                               req->wb_index, NFS_PAGE_TAG_COMMIT);
+       if (nfs_clear_request_commit(req) &&
+                       radix_tree_tag_clear(&NFS_I(inode)->nfs_page_tree,
+                               req->wb_index, NFS_PAGE_TAG_COMMIT) != NULL)
+               NFS_I(inode)->ncommit--;
 
        /* Okay, the request matches. Update the region */
        if (offset < req->wb_offset) {
index 384ea3e..309217f 100644 (file)
@@ -166,6 +166,7 @@ struct nfs_inode {
        struct radix_tree_root  nfs_page_tree;
 
        unsigned long           npages;
+       unsigned long           ncommit;
 
        /* Open contexts for shared mmap writes */
        struct list_head        open_files;