Kernel

Bug#587665: [Pkg-sysvinit-devel] Bug#587665: Safety of early boot init of /dev/random seed
On Thu, 15 Jul 2010, Matt Mackall wrote: Don't bother fiddling with the pool size. We don't, but local admins often do, probably in an attempt to better handle bursts of entropy drainage. So, we do want to properly support non-standard pool sizes in Debian if we can. Unless they're m... 16 Jul 2010 09:54

[RFC][PATCH 00/16] kill unnecessary bdi wakeups + cleanups
Hi, here is a series of patches which lessens amount of unnecessary wake-ups in the linux kernel. THE PROBLEM ~~~~~~~~~~~ Each block device has corresponding "flusher" thread, which are usually seen as "flusher-x:y" in your 'ps' output. Flusher threads are responsible to do background write-back for differ... 16 Jul 2010 09:54

[RFC][PATCH 01/16] writeback: do not self-wakeup
From: Artem Bityutskiy <Artem.Bityutskiy(a)nokia.com> The bdi forker thread wakes up itself via 'bdi_add_to_pending()'. And the thread is the only user of 'bdi_add_to_pending()'. Thus, we can safely zap the unneeded 'wake_up_process()' call. Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy(a)nokia.com> --- mm/b... 16 Jul 2010 09:54

[RFC][PATCH 06/16] writeback: improve bdi_has_dirty_io
From: Artem Bityutskiy <Artem.Bityutskiy(a)nokia.com> This patch is of clean-up type. Currently the purpose of the 'bdi_has_dirty_io()' function is not very clear - it is equivalent to 'wb_has_dirty_io()' and there is little point for it to exist. It is used inconsistently as well, e.g., in 'bdi_forker_thread()' w... 16 Jul 2010 09:54

[RFC][PATCH 07/16] writeback: do not lose wake-ups in the forker thread
From: Artem Bityutskiy <Artem.Bityutskiy(a)nokia.com> Currently the forker thread can lose wakeups which may lead to unnecessary delays in processing bdi works. E.g., consider the following scenario. 1. 'bdi_forker_thread()' walks the 'bdi_list', finds out there is nothing to do, and is about to finish the lo... 16 Jul 2010 09:54

[RFC][PATCH 04/16] writeback: fix possible race when shutting down bdi
From: Artem Bityutskiy <Artem.Bityutskiy(a)nokia.com> Current bdi code has the following race between 'bdi_wb_shutdown()' and 'bdi_forker_thread()'. Initial condition: BDI_pending is cleaned, bdi has no writeback thread, because it was inactive and exited, 'bdi_wb_shutdown()' and 'bdi_forker_thread()' are execut... 16 Jul 2010 09:53

[RFC][PATCH 12/16] writeback: add to bdi_list in the forker thread
From: Artem Bityutskiy <Artem.Bityutskiy(a)nokia.com> Before creating a bdi thread, the forker thread first removes the corresponding bdi from the 'bdi_list', then creates the bdi thread and wakes it up. The thread then adds itself back to the 'bdi_list'. There is no problem with this, except that it makes the lo... 16 Jul 2010 09:53

[RFC][PATCH 03/16] writeback: harmonize writeback threads naming
From: Artem Bityutskiy <Artem.Bityutskiy(a)nokia.com> The write-back code mixes words "thread" and "task" for the same things - this is not a problem, but this is still an inconsistency which makes it a bit difficult to read the code. hch: a convention I tend to use and I've seen in various places is to always u... 16 Jul 2010 09:53

[RFC][PATCH 11/16] writeback: move last_active to bdi
From: Artem Bityutskiy <Artem.Bityutskiy(a)nokia.com> bdi threads use local variable 'last_active' which stores last jiffies when the bdi thread did some useful work. Move this local variable to 'struct bdi_writeback'. This is just a preparation for the further patches which will make the forker thread decide when... 16 Jul 2010 09:53

[RFC][PATCH 08/16] writeback: do not lose default bdi wake-ups
From: Artem Bityutskiy <Artem.Bityutskiy(a)nokia.com> Currently the default bdi can lose wake ups. E.g., if 'bdi_queue_work()' is called when 'bdi_forker_thread()' is executing code after if (bdi_has_dirty_io(me->bdi)) wb_do_writeback(me, 0); but before 'set_current_state(TASK_INTERRUPTIBLE)'. This is unli... 16 Jul 2010 09:53