Commit c6a556b8 authored by Trond Myklebust's avatar Trond Myklebust
Browse files

[PATCH] NFS: Make searching and waiting on busy writeback requests more efficient. 



 Basically copies the VFS's method for tracking writebacks and applies
 it to the struct nfs_page.

 Signed-off-by: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
parent ab0a3dbe

fs/nfs/pagelist.c

+28 −1
Original line number Diff line number Diff line
@@ -111,6 +111,33 @@ void nfs_unlock_request(struct nfs_page *req) 
	nfs_release_request(req);

}



/**

 * nfs_set_page_writeback_locked - Lock a request for writeback

 * @req:

 */

int nfs_set_page_writeback_locked(struct nfs_page *req)

{

	struct nfs_inode *nfsi = NFS_I(req->wb_context->dentry->d_inode);



	if (!nfs_lock_request(req))

		return 0;

	radix_tree_tag_set(&nfsi->nfs_page_tree, req->wb_index, NFS_PAGE_TAG_WRITEBACK);

	return 1;

}



/**

 * nfs_clear_page_writeback - Unlock request and wake up sleepers

 */

void nfs_clear_page_writeback(struct nfs_page *req)

{

	struct nfs_inode *nfsi = NFS_I(req->wb_context->dentry->d_inode);



	spin_lock(&nfsi->req_lock);

	radix_tree_tag_clear(&nfsi->nfs_page_tree, req->wb_index, NFS_PAGE_TAG_WRITEBACK);

	spin_unlock(&nfsi->req_lock);

	nfs_unlock_request(req);

}



/**

 * nfs_clear_request - Free up all resources allocated to the request

 * @req:
@@ -301,7 +328,7 @@ nfs_scan_list(struct list_head *head, struct list_head *dst, 
		if (req->wb_index > idx_end)

			break;



		if (!nfs_lock_request(req))

		if (!nfs_set_page_writeback_locked(req))

			continue;

		nfs_list_remove_request(req);

		nfs_list_add_request(req, dst);

fs/nfs/read.c

+0 −3
Original line number Diff line number Diff line
@@ -173,7 +173,6 @@ static int nfs_readpage_async(struct nfs_open_context *ctx, struct inode *inode, 
	if (len < PAGE_CACHE_SIZE)

		memclear_highpage_flush(page, len, PAGE_CACHE_SIZE - len);



	nfs_lock_request(new);

	nfs_list_add_request(new, &one_request);

	nfs_pagein_one(&one_request, inode);

	return 0;
@@ -185,7 +184,6 @@ static void nfs_readpage_release(struct nfs_page *req) 


	nfs_clear_request(req);

	nfs_release_request(req);

	nfs_unlock_request(req);



	dprintk("NFS: read done (%s/%Ld %d@%Ld)\n",

			req->wb_context->dentry->d_inode->i_sb->s_id,
@@ -553,7 +551,6 @@ readpage_async_filler(void *data, struct page *page) 
	}

	if (len < PAGE_CACHE_SIZE)

		memclear_highpage_flush(page, len, PAGE_CACHE_SIZE - len);

	nfs_lock_request(new);

	nfs_list_add_request(new, desc->head);

	return 0;

}

fs/nfs/write.c

+9 −10
Original line number Diff line number Diff line
@@ -503,13 +503,12 @@ nfs_wait_on_requests(struct inode *inode, unsigned long idx_start, unsigned int 


	spin_lock(&nfsi->req_lock);

	next = idx_start;

	while (radix_tree_gang_lookup(&nfsi->nfs_page_tree, (void **)&req, next, 1)) {

	while (radix_tree_gang_lookup_tag(&nfsi->nfs_page_tree, (void **)&req, next, 1, NFS_PAGE_TAG_WRITEBACK)) {

		if (req->wb_index > idx_end)

			break;



		next = req->wb_index + 1;

		if (!NFS_WBACK_BUSY(req))

			continue;

		BUG_ON(!NFS_WBACK_BUSY(req));



		atomic_inc(&req->wb_count);

		spin_unlock(&nfsi->req_lock);
@@ -821,7 +820,7 @@ static void nfs_writepage_release(struct nfs_page *req) 
#else

	nfs_inode_remove_request(req);

#endif

	nfs_unlock_request(req);

	nfs_clear_page_writeback(req);

}



static inline int flush_task_priority(int how)
@@ -952,7 +951,7 @@ static int nfs_flush_multi(struct list_head *head, struct inode *inode, int how) 
		nfs_writedata_free(data);

	}

	nfs_mark_request_dirty(req);

	nfs_unlock_request(req);

	nfs_clear_page_writeback(req);

	return -ENOMEM;

}
@@ -1002,7 +1001,7 @@ static int nfs_flush_one(struct list_head *head, struct inode *inode, int how) 
		struct nfs_page *req = nfs_list_entry(head->next);

		nfs_list_remove_request(req);

		nfs_mark_request_dirty(req);

		nfs_unlock_request(req);

		nfs_clear_page_writeback(req);

	}

	return -ENOMEM;

}
@@ -1029,7 +1028,7 @@ nfs_flush_list(struct list_head *head, int wpages, int how) 
		req = nfs_list_entry(head->next);

		nfs_list_remove_request(req);

		nfs_mark_request_dirty(req);

		nfs_unlock_request(req);

		nfs_clear_page_writeback(req);

	}

	return error;

}
@@ -1121,7 +1120,7 @@ static void nfs_writeback_done_full(struct nfs_write_data *data, int status) 
		nfs_inode_remove_request(req);

#endif

	next:

		nfs_unlock_request(req);

		nfs_clear_page_writeback(req);

	}

}
@@ -1278,7 +1277,7 @@ nfs_commit_list(struct list_head *head, int how) 
		req = nfs_list_entry(head->next);

		nfs_list_remove_request(req);

		nfs_mark_request_commit(req);

		nfs_unlock_request(req);

		nfs_clear_page_writeback(req);

	}

	return -ENOMEM;

}
@@ -1324,7 +1323,7 @@ nfs_commit_done(struct rpc_task *task) 
		dprintk(" mismatch\n");

		nfs_mark_request_dirty(req);

	next:

		nfs_unlock_request(req);

		nfs_clear_page_writeback(req);

		res++;

	}

	sub_page_state(nr_unstable,res);

include/linux/nfs_page.h

+8 −4
Original line number Diff line number Diff line
@@ -19,6 +19,11 @@ 


#include <asm/atomic.h>



/*

 * Valid flags for the radix tree

 */

#define NFS_PAGE_TAG_WRITEBACK	1



/*

 * Valid flags for a dirty buffer

 */
@@ -62,6 +67,9 @@ extern int nfs_coalesce_requests(struct list_head *, struct list_head *, 
				  unsigned int);

extern  int nfs_wait_on_request(struct nfs_page *);

extern	void nfs_unlock_request(struct nfs_page *req);

extern  int nfs_set_page_writeback_locked(struct nfs_page *req);

extern  void nfs_clear_page_writeback(struct nfs_page *req);





/*

 * Lock the page of an asynchronous request without incrementing the wb_count
@@ -96,10 +104,6 @@ nfs_list_remove_request(struct nfs_page *req) 
{

	if (list_empty(&req->wb_list))

		return;

	if (!NFS_WBACK_BUSY(req)) {

		printk(KERN_ERR "NFS: unlocked request attempted removed from list!\n");

		BUG();

	}

	list_del_init(&req->wb_list);

	req->wb_list_head = NULL;

}