diff options
author | Artem Bityutskiy <Artem.Bityutskiy@nokia.com> | 2010-07-25 14:29:22 +0300 |
---|---|---|
committer | Jens Axboe <jaxboe@fusionio.com> | 2010-08-07 18:53:56 +0200 |
commit | 6467716a37673e8d47b4984eb19839bdad0a8353 (patch) | |
tree | 8b2bfd38d53e31c47654162d4ce9220c4424a31d /MAINTAINERS | |
parent | 253c34e9b10c30d3064be654b5b78fbc1a8b1896 (diff) | |
download | linux-3.10-6467716a37673e8d47b4984eb19839bdad0a8353.tar.gz linux-3.10-6467716a37673e8d47b4984eb19839bdad0a8353.tar.bz2 linux-3.10-6467716a37673e8d47b4984eb19839bdad0a8353.zip |
writeback: optimize periodic bdi thread wakeups
Whe the first inode for a bdi is marked dirty, we wake up the bdi thread which
should take care of the periodic background write-out. However, the write-out
will actually start only 'dirty_writeback_interval' centisecs later, so we can
delay the wake-up.
This change was requested by Nick Piggin who pointed out that if we delay the
wake-up, we weed out 2 unnecessary contex switches, which matters because
'__mark_inode_dirty()' is a hot-path function.
This patch introduces a new function - 'bdi_wakeup_thread_delayed()', which
sets up a timer to wake-up the bdi thread and returns. So the wake-up is
delayed.
We also delete the timer in bdi threads just before writing-back. And
synchronously delete it when unregistering bdi. At the unregister point the bdi
does not have any users, so no one can arm it again.
Since now we take 'bdi->wb_lock' in the timer, which can execute in softirq
context, we have to use 'spin_lock_bh()' for 'bdi->wb_lock'. This patch makes
this change as well.
This patch also moves the 'bdi_wb_init()' function down in the file to avoid
forward-declaration of 'bdi_wakeup_thread_delayed()'.
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Diffstat (limited to 'MAINTAINERS')
0 files changed, 0 insertions, 0 deletions