Messages in this thread |  | | | Date | Tue, 4 Dec 2007 01:06:06 -0800 | | From | "Michael Rubin" <> | | Subject | Re: [patch 1/1] Writeback fix for concurrent large and small file writes |
On Nov 29, 2007 5:32 PM, Fengguang Wu <wfg@mail.ustc.edu.cnwrote: > > On Nov 28, 2007 4:34 PM, Fengguang Wu <wfg@mail.ustc.edu.cn> wrote: > > > Could you demonstrate the situation? Or if I guess it right, could it > > > be fixed by the following patch?
Feng I am sorry to have been mistaken but I reran my tests and I am now finding that the patch you gave me is NOT fixing the problem. The patch I refer to is the one you posted on this thread that adds a requeue_io in __sync_single_inode.
I tarred up my test code. It is still in very rough shape but it can reproduce the issue. You can find it here:
http://neverthere.org/mhr/wb/wb-test.tar.bz2
Just make the test and run it with the args "-duration 0:5:0 -starvation". You must be root so it can set some sysctl values.
> One major concern could be whether a continuous writer dirting pages > at the 'right' pace will generate a steady flow of write I/Os which are > _tiny_hence_inefficient_. > > So it's not a problem in *theory* :-) > > > I will post this change for 2.6.24 and list Feng as author. If that's > > ok with Feng.
I am going to try to track down what is up in 2.6.24 and see if I can find a less dramatic fix than my tree patch for the short term. If you get a chance to reproduce the problem with my test on your patch that would rock.
I still would like to see my full patch accepted into 2.6.25. A patch should be arriving shortly that will incorporate my larger patch and Qi Yong's fix for skip-writing-data-pages-when-inode-is-under-i_sync. http://www.gossamer-threads.com/lists/linux/kernel/849493
As always thanks for your patience,
mrubin
|  |