From b616844310a6c8a4ab405d3436bbb6e53cfd852f Mon Sep 17 00:00:00 2001 From: Theodore Ts'o Date: Mon, 28 Feb 2011 13:12:38 -0500 Subject: ext4: optimize ext4_bio_write_page() when no extent conversion is needed If no extent conversion is required, wake up any processes waiting for the page's writeback to be complete and free the ext4_io_end structure directly in ext4_end_bio() instead of dropping it on the linked list (which requires taking a spinlock to queue and dequeue the io_end structure), and waiting for the workqueue to do this work. This removes an extra scheduling delay before process waiting for an fsync() to complete gets woken up, and it also reduces the CPU overhead for a random write workload. Signed-off-by: "Theodore Ts'o" --- fs/ext4/page-io.c | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'fs/ext4') diff --git a/fs/ext4/page-io.c b/fs/ext4/page-io.c index d5c391ffad7..0cfd03e19d7 100644 --- a/fs/ext4/page-io.c +++ b/fs/ext4/page-io.c @@ -259,6 +259,11 @@ static void ext4_end_bio(struct bio *bio, int error) bi_sector >> (inode->i_blkbits - 9)); } + if (!(io_end->flag & EXT4_IO_END_UNWRITTEN)) { + ext4_free_io_end(io_end); + return; + } + /* Add the io_end to per-inode completed io list*/ spin_lock_irqsave(&EXT4_I(inode)->i_completed_io_lock, flags); list_add_tail(&io_end->list, &EXT4_I(inode)->i_completed_io_list); -- cgit v1.2.3-18-g5258