From: Chao Yu Date: Thu, 5 Feb 2015 10:01:39 +0000 (+0800) Subject: f2fs: support fast lookup in extent cache X-Git-Tag: omap-for-v4.2/o2_dc~90^2~56 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=62c8af651b37490c18a42c02586fa6a4fb39320a;p=pandora-kernel.git f2fs: support fast lookup in extent cache This patch adds a fast lookup path for rb-tree extent cache. In this patch we add a recently accessed extent node pointer 'cached_en' in extent tree. In lookup path of extent cache, we will firstly lookup the last accessed extent node which cached_en points, if we do not hit in this node, we will try to lookup extent node in rb-tree. By this way we can avoid unnecessary slow lookup in rb-tree sometimes. Note that, side-effect of this patch is that we will increase memory cost, because we will store a pointer variable in each struct extent tree additionally. Signed-off-by: Chao Yu Signed-off-by: Jaegeuk Kim --- Reading git-diff-tree failed