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Commit 27e88bf6 authored by Felix Blyakher's avatar Felix Blyakher
Browse files

Revert "[XFS] remove old vmap cache" 



This reverts commit d2859751.

This commit caused regression. We'll try to fix use of new
vmap API for next release.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarFelix Blyakher <felixb@sgi.com>
parent 7fdf5824

fs/xfs/linux-2.6/xfs_buf.c

+74 −1
Original line number Diff line number Diff line
@@ -165,6 +165,75 @@ test_page_region( 
	return (mask && (page_private(page) & mask) == mask);

}



/*

 *	Mapping of multi-page buffers into contiguous virtual space

 */



typedef struct a_list {

	void		*vm_addr;

	struct a_list	*next;

} a_list_t;



static a_list_t		*as_free_head;

static int		as_list_len;

static DEFINE_SPINLOCK(as_lock);



/*

 *	Try to batch vunmaps because they are costly.

 */

STATIC void

free_address(

	void		*addr)

{

	a_list_t	*aentry;



#ifdef CONFIG_XEN

	/*

	 * Xen needs to be able to make sure it can get an exclusive

	 * RO mapping of pages it wants to turn into a pagetable.  If

	 * a newly allocated page is also still being vmap()ed by xfs,

	 * it will cause pagetable construction to fail.  This is a

	 * quick workaround to always eagerly unmap pages so that Xen

	 * is happy.

	 */

	vunmap(addr);

	return;

#endif



	aentry = kmalloc(sizeof(a_list_t), GFP_NOWAIT);

	if (likely(aentry)) {

		spin_lock(&as_lock);

		aentry->next = as_free_head;

		aentry->vm_addr = addr;

		as_free_head = aentry;

		as_list_len++;

		spin_unlock(&as_lock);

	} else {

		vunmap(addr);

	}

}



STATIC void

purge_addresses(void)

{

	a_list_t	*aentry, *old;



	if (as_free_head == NULL)

		return;



	spin_lock(&as_lock);

	aentry = as_free_head;

	as_free_head = NULL;

	as_list_len = 0;

	spin_unlock(&as_lock);



	while ((old = aentry) != NULL) {

		vunmap(aentry->vm_addr);

		aentry = aentry->next;

		kfree(old);

	}

}



/*

 *	Internal xfs_buf_t object manipulation

 */
@@ -264,7 +333,7 @@ xfs_buf_free( 
		uint		i;



		if ((bp->b_flags & XBF_MAPPED) && (bp->b_page_count > 1))

                       vunmap(bp->b_addr - bp->b_offset);

			free_address(bp->b_addr - bp->b_offset);



		for (i = 0; i < bp->b_page_count; i++) {

			struct page	*page = bp->b_pages[i];
@@ -386,6 +455,8 @@ _xfs_buf_map_pages( 
		bp->b_addr = page_address(bp->b_pages[0]) + bp->b_offset;

		bp->b_flags |= XBF_MAPPED;

	} else if (flags & XBF_MAPPED) {

		if (as_list_len > 64)

			purge_addresses();

		bp->b_addr = vmap(bp->b_pages, bp->b_page_count,

					VM_MAP, PAGE_KERNEL);

		if (unlikely(bp->b_addr == NULL))
@@ -1672,6 +1743,8 @@ xfsbufd( 
			count++;

		}



		if (as_list_len > 0)

			purge_addresses();

		if (count)

			blk_run_address_space(target->bt_mapping);