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Revert "[XFS] remove old vmap cache" 

This reverts commit d2859751cd.

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

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Felix Blyakher <felixb@sgi.com>
This commit is contained in:
Felix Blyakher 2009-02-18 15:56:51 -06:00
parent 7fdf582447
commit 27e88bf6af
1 changed files with 74 additions and 1 deletions
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75
fs/xfs/linux-2.6/xfs_buf.c
View File

@ -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);