From: jing zhang Subject: [PATCH] ext4: add rb_tree cache to struct ext4_group_info Date: Sun, 28 Mar 2010 17:11:55 +0800 Message-ID: Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Cc: "Theodore Ts'o" , Andreas Dilger , Dave Kleikamp , "Aneesh Kumar K. V" To: linux-ext4 Return-path: Received: from mail-yw0-f172.google.com ([209.85.211.172]:60222 "EHLO mail-yw0-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753907Ab0C1JL5 (ORCPT ); Sun, 28 Mar 2010 05:11:57 -0400 Received: by ywh2 with SMTP id 2so4362471ywh.33 for ; Sun, 28 Mar 2010 02:11:56 -0700 (PDT) Sender: linux-ext4-owner@vger.kernel.org List-ID: From: Jing Zhang Date: Sun Mar 28 17:09:33 2010 rb_tree cache is added to struct ext4_group_info at minor cost. Cc: Theodore Ts'o Cc: Andreas Dilger Cc: Dave Kleikamp Cc: "Aneesh Kumar K. V" Signed-off-by: Jing Zhang --- --- linux-2.6.32/fs/ext4/ext4.h 2009-12-03 11:51:22.000000000 +0800 +++ ext4_mm_leak/ext4-12.h 2010-03-28 16:47:56.000000000 +0800 @@ -1622,6 +1622,7 @@ static inline void ext4_update_i_disksiz struct ext4_group_info { unsigned long bb_state; struct rb_root bb_free_root; + struct rb_node *bb_free_cache; ext4_grpblk_t bb_first_free; /* first free block */ ext4_grpblk_t bb_free; /* total free blocks */ ext4_grpblk_t bb_fragments; /* nr of freespace fragments */ --- linux-2.6.32/fs/ext4/mballoc.c 2009-12-03 11:51:22.000000000 +0800 +++ ext4_mm_leak/mballoc-12.c 2010-03-28 16:43:08.000000000 +0800 @@ -2548,6 +2548,8 @@ static void release_blocks_on_commit(jou count2++; ext4_lock_group(sb, entry->group); /* Take it out of per group rb tree */ + if (db->bb_free_cache == &entry->node) + db->bb_free_cache = rb_next(&entry->node); rb_erase(&entry->node, &(db->bb_free_root)); mb_free_blocks(NULL, &e4b, entry->start_blk, entry->count); @@ -3188,7 +3190,10 @@ static void ext4_mb_generate_from_freeli struct ext4_free_data *entry; grp = ext4_get_group_info(sb, group); - n = rb_first(&(grp->bb_free_root)); + if (grp->bb_free_cache) + n = grp->bb_free_cache; + else + n = rb_first(&(grp->bb_free_root)); while (n) { entry = rb_entry(n, struct ext4_free_data, node); @@ -4353,6 +4358,7 @@ ext4_mb_free_metadata(handle_t *handle, struct ext4_sb_info *sbi = EXT4_SB(sb); struct rb_node **n = &db->bb_free_root.rb_node, *node; struct rb_node *parent = NULL, *new_node; + int left = 1; BUG_ON(!ext4_handle_valid(handle)); BUG_ON(e4b->bd_bitmap_page == NULL); @@ -4369,6 +4375,8 @@ ext4_mb_free_metadata(handle_t *handle, * blocks */ page_cache_get(e4b->bd_buddy_page); page_cache_get(e4b->bd_bitmap_page); + /* just for sure */ + db->bb_free_cache = 0; } while (*n) { parent = *n; @@ -4376,7 +4384,7 @@ ext4_mb_free_metadata(handle_t *handle, if (block < entry->start_blk) n = &(*n)->rb_left; else if (block >= (entry->start_blk + entry->count)) - n = &(*n)->rb_right; + n = &(*n)->rb_right, left = 0; else { ext4_grp_locked_error(sb, e4b->bd_group, __func__, "Double free of blocks %d (%d %d)", @@ -4387,6 +4395,8 @@ ext4_mb_free_metadata(handle_t *handle, rb_link_node(new_node, parent, n); rb_insert_color(new_node, &db->bb_free_root); + if (left) + db->bb_free_cache = new_node; /* Now try to see the extent can be merged to left and right */ node = rb_prev(new_node);