Commit b6168443 authored by Theodore Ts'o's avatar Theodore Ts'o

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: default avatar"Theodore Ts'o" <tytso@mit.edu>
parent d39195c3
...@@ -259,6 +259,11 @@ static void ext4_end_bio(struct bio *bio, int error) ...@@ -259,6 +259,11 @@ static void ext4_end_bio(struct bio *bio, int error)
bi_sector >> (inode->i_blkbits - 9)); 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*/ /* Add the io_end to per-inode completed io list*/
spin_lock_irqsave(&EXT4_I(inode)->i_completed_io_lock, flags); spin_lock_irqsave(&EXT4_I(inode)->i_completed_io_lock, flags);
list_add_tail(&io_end->list, &EXT4_I(inode)->i_completed_io_list); list_add_tail(&io_end->list, &EXT4_I(inode)->i_completed_io_list);
......
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