David Sterba
2013-Feb-28 14:54 UTC
[PATCH] btrfs: use only inline_pages from extent buffer
The nodesize is capped at 64k and there are enough pages preallocated in
extent_buffer::inline_pages. The fallback to kmalloc never happened
because even on the smallest page size considered (4k) inline_pages
covered the needs.
Signed-off-by: David Sterba <dsterba@suse.cz>
---
fs/btrfs/extent_io.c | 21 ++++++---------------
fs/btrfs/extent_io.h | 3 +--
2 files changed, 7 insertions(+), 17 deletions(-)
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 597ab89..0306665 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -3981,8 +3981,6 @@ static void __free_extent_buffer(struct extent_buffer *eb)
list_del(&eb->leak_list);
spin_unlock_irqrestore(&leak_lock, flags);
#endif
- if (eb->pages && eb->pages != eb->inline_pages)
- kfree(eb->pages);
kmem_cache_free(extent_buffer_cache, eb);
}
@@ -4023,19 +4021,12 @@ static struct extent_buffer
*__alloc_extent_buffer(struct extent_io_tree *tree,
atomic_set(&eb->refs, 1);
atomic_set(&eb->io_pages, 0);
- if (len > MAX_INLINE_EXTENT_BUFFER_SIZE) {
- struct page **pages;
- int num_pages = (len + PAGE_CACHE_SIZE - 1) >>
- PAGE_CACHE_SHIFT;
- pages = kzalloc(num_pages, mask);
- if (!pages) {
- __free_extent_buffer(eb);
- return NULL;
- }
- eb->pages = pages;
- } else {
- eb->pages = eb->inline_pages;
- }
+ /*
+ * Sanity checks, currently the maximum is 64k covered by 16x 4k pages
+ */
+ BUILD_BUG_ON(BTRFS_MAX_METADATA_BLOCKSIZE
+ > MAX_INLINE_EXTENT_BUFFER_SIZE);
+ BUG_ON(len > MAX_INLINE_EXTENT_BUFFER_SIZE);
return eb;
}
diff --git a/fs/btrfs/extent_io.h b/fs/btrfs/extent_io.h
index dc81868..6068a19 100644
--- a/fs/btrfs/extent_io.h
+++ b/fs/btrfs/extent_io.h
@@ -158,8 +158,7 @@ struct extent_buffer {
*/
wait_queue_head_t read_lock_wq;
wait_queue_head_t lock_wq;
- struct page *inline_pages[INLINE_EXTENT_BUFFER_PAGES];
- struct page **pages;
+ struct page *pages[INLINE_EXTENT_BUFFER_PAGES];
};
static inline void extent_set_compress_type(unsigned long *bio_flags,
--
1.8.1.4
--
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