NFS: Use cond_resched_lock() to reduce latencies in the commit scans

Ensure that we conditionally drop the inode->i_lock when it is safe
to do so in the commit loops.
We do so after locking the nfs_page, but before removing it from the
commit list. We can then use list_safe_reset_next to recover the loop
after the lock is retaken.

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

1 files changed, 4 insertions, 4 deletions

diff --git a/fs/nfs/pnfs.h b/fs/nfs/pnfs.h
index e98ff3027d3a..07802652f5a3 100644
--- a/fs/nfs/pnfs.h
+++ b/fs/nfs/pnfs.h
@@ -97,7 +97,7 @@ struct pnfs_layoutdriver_type {
         void (*mark_request_commit) (struct nfs_page *req,
                                         struct pnfs_layout_segment *lseg);
         void (*clear_request_commit) (struct nfs_page *req);
-        int (*scan_commit_lists) (struct inode *inode, int max);
+        int (*scan_commit_lists) (struct inode *inode, int max, spinlock_t *lock);
         int (*commit_pagelist)(struct inode *inode, struct list_head *mds_pages, int how);
 
         /*
@@ -294,14 +294,14 @@ pnfs_clear_request_commit(struct nfs_page *req)
 }
 
 static inline int
-pnfs_scan_commit_lists(struct inode *inode, int max)
+pnfs_scan_commit_lists(struct inode *inode, int max, spinlock_t *lock)
 {
         struct pnfs_layoutdriver_type *ld = NFS_SERVER(inode)->pnfs_curr_ld;
         int ret;
 
         if (ld == NULL || ld->scan_commit_lists == NULL)
                 return 0;
-        ret = ld->scan_commit_lists(inode, max);
+        ret = ld->scan_commit_lists(inode, max, lock);
         if (ret != 0)
                 set_bit(NFS_INO_PNFS_COMMIT, &NFS_I(inode)->flags);
         return ret;
@@ -419,7 +419,7 @@ pnfs_clear_request_commit(struct nfs_page *req)
 }
 
 static inline int
-pnfs_scan_commit_lists(struct inode *inode, int max)
+pnfs_scan_commit_lists(struct inode *inode, int max, spinlock_t *lock)
 {
         return 0;
 }