Messages in this thread | | | Date | Fri, 28 Sep 2007 01:27:18 -0700 | From | "Chakri n" <> | Subject | Re: A unresponsive file system can hang all I/O in the system on linux-2.6.23-rc6 (dirty_thresh problem?) |
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Thanks.
The BDI dirty limits sounds like a good idea.
Is there already a patch for this, which I could try?
I believe it works like this,
Each BDI, will have a limit. If the dirty_thresh exceeds the limit, all the I/O on the block device will be synchronous.
so, if I have sda & a NFS mount, the dirty limit can be different for each of them.
I can set dirty limit for - sda to be 90% and - NFS mount to be 50%.
So, if the dirty limit is greater than 50%, NFS does synchronously, but sda can work asynchronously, till dirty limit reaches 90%.
Thanks --Chakri
On 9/27/07, Peter Zijlstra <a.p.zijlstra@chello.nl> wrote: > On Thu, 2007-09-27 at 23:50 -0700, Andrew Morton wrote: > > > What we _don't_ want to happen is for other processes which are writing to > > other, non-dead devices to get collaterally blocked. We have patches which > > might fix that queued for 2.6.24. Peter? > > Nasty problem, don't do that :-) > > But yeah, with per BDI dirty limits we get stuck at whatever ratio that > NFS server/mount (?) has - which could be 100%. Other processes will > then work almost synchronously against their BDIs but it should work. > > [ They will lower the NFS-BDI's ratio, but some fancy clipping code will > limit the other BDIs their dirty limit to not exceed the total limit. > And with all these NFS pages stuck, that will still be nothing. ] > > > > - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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