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Btrfs: extent_map optimizations to cut down on CPU usage

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Signed-off-by: Chris Mason <chris.mason@oracle.com>
This commit is contained in:
Chris Mason
2007-10-15 16:18:55 -04:00
parent 3326d1b07c
commit 810191ff30
6 changed files with 40 additions and 91 deletions
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33
fs/btrfs/extent_map.c
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@@ -1963,9 +1963,9 @@ static inline struct page *extent_buffer_page(struct extent_buffer *eb,
struct page *p;
if (i == 0)
return eb->last_page;
return eb->first_page;
i += eb->start >> PAGE_CACHE_SHIFT;
p = find_get_page(eb->last_page->mapping, i);
p = find_get_page(eb->first_page->mapping, i);
page_cache_release(p);
return p;
}
@@ -2037,7 +2037,7 @@ struct extent_buffer *alloc_extent_buffer(struct extent_map_tree *tree,
}
set_page_extent_mapped(p);
if (i == 0)
eb->last_page = p;
eb->first_page = p;
if (!PageUptodate(p))
uptodate = 0;
unlock_page(p);
@@ -2083,7 +2083,7 @@ struct extent_buffer *find_extent_buffer(struct extent_map_tree *tree,
}
set_page_extent_mapped(p);
if (i == 0)
eb->last_page = p;
eb->first_page = p;
if (!PageUptodate(p))
uptodate = 0;
unlock_page(p);
@@ -2169,7 +2169,15 @@ EXPORT_SYMBOL(wait_on_extent_buffer_writeback);
int set_extent_buffer_dirty(struct extent_map_tree *tree,
struct extent_buffer *eb)
{
return set_range_dirty(tree, eb->start, eb->start + eb->len - 1);
unsigned long i;
unsigned long num_pages;
num_pages = num_extent_pages(eb->start, eb->len);
for (i = 0; i < num_pages; i++) {
__set_page_dirty_nobuffers(extent_buffer_page(eb, i));
}
return set_extent_dirty(tree, eb->start,
eb->start + eb->len - 1, GFP_NOFS);
}
EXPORT_SYMBOL(set_extent_buffer_dirty);
@@ -2317,16 +2325,11 @@ static int __map_extent_buffer(struct extent_buffer *eb, unsigned long start,
size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
unsigned long end_i = (start_offset + start + min_len) >>
PAGE_CACHE_SHIFT;
PAGE_CACHE_SHIFT;
if (i != end_i)
return -EINVAL;
if (start >= eb->len) {
printk("bad start in map eb start %Lu len %lu caller start %lu min %lu\n", eb->start, eb->len, start, min_len);
WARN_ON(1);
}
if (i == 0) {
offset = start_offset;
*map_start = 0;
@@ -2353,14 +2356,6 @@ int map_extent_buffer(struct extent_buffer *eb, unsigned long start,
int err;
int save = 0;
if (eb->map_token) {
if (start >= eb->map_start &&
start + min_len <= eb->map_start + eb->map_len) {
*token = eb->map_token;
*map = eb->kaddr;
*map_start = eb->map_start;
*map_len = eb->map_len;
return 0;
}
unmap_extent_buffer(eb, eb->map_token, km);
eb->map_token = NULL;
save = 1;