Commits
Namjae Jeon committed 99600051b04
udf: add extent cache support in case of file reading This patch implements extent caching in case of file reading. While reading a file, currently, UDF reads metadata serially which takes a lot of time depending on the number of extents present in the file. Caching last accessd extent improves metadata read time. Instead of reading file metadata from start, now we read from the cached extent. This patch considerably improves the time spent by CPU in kernel mode. For example, while reading a 10.9 GB file using dd: Time before applying patch: 11677022208 bytes (10.9GB) copied, 1529.748921 seconds, 7.3MB/s real 25m 29.85s user 0m 12.41s sys 15m 34.75s Time after applying patch: 11677022208 bytes (10.9GB) copied, 1469.338231 seconds, 7.6MB/s real 24m 29.44s user 0m 15.73s sys 3m 27.61s [JK: Fix bh refcounting issues, simplify initialization] Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com> Signed-off-by: Ashish Sangwan <a.sangwan@samsung.com> Signed-off-by: Bonggil Bak <bgbak@samsung.com> Signed-off-by: Jan Kara <jack@suse.cz>