Messages in this thread | | | Date | Fri, 23 Sep 2005 10:45:29 +0200 | From | Andrea Arcangeli <> | Subject | Re: 2.6.14-rc2-mm1 - ext3 wedging up |
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On Fri, Sep 23, 2005 at 03:20:33AM -0400, Valdis.Kletnieks@vt.edu wrote: > On Fri, 23 Sep 2005 10:36:16 +1000, Con Kolivas said: > > (Adding Andrea to the To: list...) > > > On Fri, 23 Sep 2005 05:59, Valdis.Kletnieks@vt.edu wrote: > > > Am seeing reproducible wedging up when writing large (20M+) files to an > > > ext3 file system. Oddly enough, if something *else* writes files to the > > > file system as well, it will unwedge for a while and make progress. Also,
So you get a total hang? I guess there's a bug somewhere...
> I'm pretty convinced that for this patch to work, it *will* need feedback from > the actual (not max) disk bandwidth and possibly the actual amount of RAM - > what works on Andrea's 1G workstation with (presumably) a real disk system > is waay too much for 256M and a single laptop-class disk.
That's not the problem here if you get a total hang. This heuristic should only reduce the amount of dirty memory, it should never grind a task to a total hang, until some other task writes to the filesystem.
The sysrq shows the task sleeping in blk_congestion_wait.
> For now, I'm leaving centisecs set to 40, and will see how that works - most > of my "problem cases" involve an FTP on a 10/100mbit connection, so that will > get tried tomorrow.....
You should leave it to 0 until I find the buglet that hangs the system.
I'll have a look.
One other thing to change is to call balance_dirty only when the dirty bit is toggled (so overwrites of dirty cache are not accounted, since they generate no additional I/O on disk).
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