To explain the pages allocated from mempool state->pool can be
swapped in __btree_sort(), because state->pool is a page pool,
which allocates pages by alloc_pages() indeed.
Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
* Our temporary buffer is the same size as the btree node's
* buffer, we can just swap buffers instead of doing a big
* memcpy()
+ *
+ * Don't worry event 'out' is allocated from mempool, it can
+ * still be swapped here. Because state->pool is a page mempool
+ * creaated by by mempool_init_page_pool(), which allocates
+ * pages by alloc_pages() indeed.
*/
out->magic = b->set->data->magic;