Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit e965f963 authored by Christoph Lameter's avatar Christoph Lameter Committed by Linus Torvalds
Browse files

[PATCH] Direct Migration V9: Avoid writeback / page_migrate() method 



Migrate a page with buffers without requiring writeback

This introduces a new address space operation migratepage() that may be used
by a filesystem to implement its own version of page migration.

A version is provided that migrates buffers attached to pages.  Some
filesystems (ext2, ext3, xfs) are modified to utilize this feature.

The swapper address space operation are modified so that a regular
migrate_page() will occur for anonymous pages without writeback (migrate_pages
forces every anonymous page to have a swap entry).

Signed-off-by: default avatarMike Kravetz <kravetz@us.ibm.com>
Signed-off-by: default avatarChristoph Lameter <clameter@sgi.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 7e2ab150

fs/buffer.c

+60 −0
Original line number Original line Diff line number Diff line
@@ -3049,6 +3049,66 @@ asmlinkage long sys_bdflush(int func, long data) 
	return 0;

	return 0;

}

}





/*

 * Migration function for pages with buffers. This function can only be used

 * if the underlying filesystem guarantees that no other references to "page"

 * exist.

 */

#ifdef CONFIG_MIGRATION

int buffer_migrate_page(struct page *newpage, struct page *page)

{

	struct address_space *mapping = page->mapping;

	struct buffer_head *bh, *head;



	if (!mapping)

		return -EAGAIN;



	if (!page_has_buffers(page))

		return migrate_page(newpage, page);



	head = page_buffers(page);



	if (migrate_page_remove_references(newpage, page, 3))

		return -EAGAIN;



	bh = head;

	do {

		get_bh(bh);

		lock_buffer(bh);

		bh = bh->b_this_page;



	} while (bh != head);



	ClearPagePrivate(page);

	set_page_private(newpage, page_private(page));

	set_page_private(page, 0);

	put_page(page);

	get_page(newpage);



	bh = head;

	do {

		set_bh_page(bh, newpage, bh_offset(bh));

		bh = bh->b_this_page;



	} while (bh != head);



	SetPagePrivate(newpage);



	migrate_page_copy(newpage, page);



	bh = head;

	do {

		unlock_buffer(bh);

 		put_bh(bh);

		bh = bh->b_this_page;



	} while (bh != head);



	return 0;

}

EXPORT_SYMBOL(buffer_migrate_page);

#endif



/*

/*

 * Buffer-head allocation

 * Buffer-head allocation

 */

 */

fs/ext2/inode.c

+2 −0
Original line number Original line Diff line number Diff line
@@ -706,6 +706,7 @@ struct address_space_operations ext2_aops = { 
	.bmap			= ext2_bmap,

	.bmap			= ext2_bmap,

	.direct_IO		= ext2_direct_IO,

	.direct_IO		= ext2_direct_IO,

	.writepages		= ext2_writepages,

	.writepages		= ext2_writepages,

	.migratepage		= buffer_migrate_page,

};

};





struct address_space_operations ext2_aops_xip = {

struct address_space_operations ext2_aops_xip = {
@@ -723,6 +724,7 @@ struct address_space_operations ext2_nobh_aops = { 
	.bmap			= ext2_bmap,

	.bmap			= ext2_bmap,

	.direct_IO		= ext2_direct_IO,

	.direct_IO		= ext2_direct_IO,

	.writepages		= ext2_writepages,

	.writepages		= ext2_writepages,

	.migratepage		= buffer_migrate_page,

};

};





/*

/*

fs/ext3/inode.c

+2 −0
Original line number Original line Diff line number Diff line
@@ -1559,6 +1559,7 @@ static struct address_space_operations ext3_ordered_aops = { 
	.invalidatepage	= ext3_invalidatepage,

	.invalidatepage	= ext3_invalidatepage,

	.releasepage	= ext3_releasepage,

	.releasepage	= ext3_releasepage,

	.direct_IO	= ext3_direct_IO,

	.direct_IO	= ext3_direct_IO,

	.migratepage	= buffer_migrate_page,

};

};





static struct address_space_operations ext3_writeback_aops = {

static struct address_space_operations ext3_writeback_aops = {
@@ -1572,6 +1573,7 @@ static struct address_space_operations ext3_writeback_aops = { 
	.invalidatepage	= ext3_invalidatepage,

	.invalidatepage	= ext3_invalidatepage,

	.releasepage	= ext3_releasepage,

	.releasepage	= ext3_releasepage,

	.direct_IO	= ext3_direct_IO,

	.direct_IO	= ext3_direct_IO,

	.migratepage	= buffer_migrate_page,

};

};





static struct address_space_operations ext3_journalled_aops = {

static struct address_space_operations ext3_journalled_aops = {

fs/xfs/linux-2.6/xfs_aops.c

+1 −0
Original line number Original line Diff line number Diff line
@@ -1462,4 +1462,5 @@ struct address_space_operations linvfs_aops = { 
	.commit_write		= generic_commit_write,

	.commit_write		= generic_commit_write,

	.bmap			= linvfs_bmap,

	.bmap			= linvfs_bmap,

	.direct_IO		= linvfs_direct_IO,

	.direct_IO		= linvfs_direct_IO,

	.migratepage		= buffer_migrate_page,

};
 
};

fs/xfs/linux-2.6/xfs_buf.c

+1 −0
Original line number Original line Diff line number Diff line
@@ -1521,6 +1521,7 @@ xfs_mapping_buftarg( 
	struct address_space	*mapping;

	struct address_space	*mapping;

	static struct address_space_operations mapping_aops = {

	static struct address_space_operations mapping_aops = {

		.sync_page = block_sync_page,

		.sync_page = block_sync_page,

		.migratepage = fail_migrate_page,

	};

	};





	inode = new_inode(bdev->bd_inode->i_sb);

	inode = new_inode(bdev->bd_inode->i_sb);