Btrfs: CPU usage optimizations in push and the extent_map code

Signed-off-by: Chris Mason <chris.mason@oracle.com>

1 files changed, 15 insertions, 30 deletions

diff --git a/fs/btrfs/extent_map.c b/fs/btrfs/extent_map.c
index 3c81f5eab155..caaf0bf0e059 100644
--- a/fs/btrfs/extent_map.c
+++ b/fs/btrfs/extent_map.c
@@ -1986,12 +1986,15 @@ static inline struct page *extent_buffer_page(struct extent_buffer *eb,
                                               unsigned long i)
 {
         struct page *p;
+        struct address_space *mapping;
 
         if (i == 0)
                 return eb->first_page;
         i += eb->start >> PAGE_CACHE_SHIFT;
-        p = find_get_page(eb->first_page->mapping, i);
-        page_cache_release(p);
+        mapping = eb->first_page->mapping;
+        read_lock_irq(&mapping->tree_lock);
+        p = radix_tree_lookup(&mapping->page_tree, i);
+        read_unlock_irq(&mapping->tree_lock);
         return p;
 }
 
@@ -2365,9 +2368,7 @@ void read_extent_buffer(struct extent_buffer *eb, void *dstv,
         WARN_ON(start > eb->len);
         WARN_ON(start + len > eb->start + eb->len);
 
-        offset = start & ((unsigned long)PAGE_CACHE_SIZE - 1);
-        if (i == 0)
-                offset += start_offset;
+        offset = (start_offset + start) & ((unsigned long)PAGE_CACHE_SIZE - 1);
 
         while(len > 0) {
                 page = extent_buffer_page(eb, i);
@@ -2475,9 +2476,7 @@ int memcmp_extent_buffer(struct extent_buffer *eb, const void *ptrv,
         WARN_ON(start > eb->len);
         WARN_ON(start + len > eb->start + eb->len);
 
-        offset = start & ((unsigned long)PAGE_CACHE_SIZE - 1);
-        if (i == 0)
-                offset += start_offset;
+        offset = (start_offset + start) & ((unsigned long)PAGE_CACHE_SIZE - 1);
 
         while(len > 0) {
                 page = extent_buffer_page(eb, i);
@@ -2514,9 +2513,7 @@ void write_extent_buffer(struct extent_buffer *eb, const void *srcv,
         WARN_ON(start > eb->len);
         WARN_ON(start + len > eb->start + eb->len);
 
-        offset = start & ((unsigned long)PAGE_CACHE_SIZE - 1);
-        if (i == 0)
-                offset += start_offset;
+        offset = (start_offset + start) & ((unsigned long)PAGE_CACHE_SIZE - 1);
 
         while(len > 0) {
                 page = extent_buffer_page(eb, i);
@@ -2548,9 +2545,7 @@ void memset_extent_buffer(struct extent_buffer *eb, char c,
         WARN_ON(start > eb->len);
         WARN_ON(start + len > eb->start + eb->len);
 
-        offset = start & ((unsigned long)PAGE_CACHE_SIZE - 1);
-        if (i == 0)
-                offset += start_offset;
+        offset = (start_offset + start) & ((unsigned long)PAGE_CACHE_SIZE - 1);
 
         while(len > 0) {
                 page = extent_buffer_page(eb, i);
@@ -2582,9 +2577,8 @@ void copy_extent_buffer(struct extent_buffer *dst, struct extent_buffer *src,
 
         WARN_ON(src->len != dst_len);
 
-        offset = dst_offset & ((unsigned long)PAGE_CACHE_SIZE - 1);
-        if (i == 0)
-                offset += start_offset;
+        offset = (start_offset + dst_offset) &
+                ((unsigned long)PAGE_CACHE_SIZE - 1);
 
         while(len > 0) {
                 page = extent_buffer_page(dst, i);
@@ -2664,19 +2658,14 @@ void memcpy_extent_buffer(struct extent_buffer *dst, unsigned long dst_offset,
         }
 
         while(len > 0) {
-                dst_off_in_page = dst_offset &
+                dst_off_in_page = (start_offset + dst_offset) &
                         ((unsigned long)PAGE_CACHE_SIZE - 1);
-                src_off_in_page = src_offset &
+                src_off_in_page = (start_offset + src_offset) &
                         ((unsigned long)PAGE_CACHE_SIZE - 1);
 
                 dst_i = (start_offset + dst_offset) >> PAGE_CACHE_SHIFT;
                 src_i = (start_offset + src_offset) >> PAGE_CACHE_SHIFT;
 
-                if (src_i == 0)
-                        src_off_in_page += start_offset;
-                if (dst_i == 0)
-                        dst_off_in_page += start_offset;
-
                 cur = min(len, (unsigned long)(PAGE_CACHE_SIZE -
                                                src_off_in_page));
                 cur = min_t(unsigned long, cur,
@@ -2723,14 +2712,10 @@ void memmove_extent_buffer(struct extent_buffer *dst, unsigned long dst_offset,
                 dst_i = (start_offset + dst_end) >> PAGE_CACHE_SHIFT;
                 src_i = (start_offset + src_end) >> PAGE_CACHE_SHIFT;
 
-                dst_off_in_page = dst_end &
+                dst_off_in_page = (start_offset + dst_end) &
                         ((unsigned long)PAGE_CACHE_SIZE - 1);
-                src_off_in_page = src_end &
+                src_off_in_page = (start_offset + src_end) &
                         ((unsigned long)PAGE_CACHE_SIZE - 1);
-                if (src_i == 0)
-                        src_off_in_page += start_offset;
-                if (dst_i == 0)
-                        dst_off_in_page += start_offset;
 
                 cur = min_t(unsigned long, len, src_off_in_page + 1);
                 cur = min(cur, dst_off_in_page + 1);