Messages in this thread | | | Date | Mon, 10 Mar 1997 17:44:13 -0500 (EST) | From | Jason Duerstock <> | Subject | Re: Couldn't get a free page |
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On Mon, 10 Mar 1997, Richard B. Johnson wrote:
> On Mon, 10 Mar 1997, Leonard N. Zubkoff wrote: > > > From: "Richard B. Johnson" <root@analogic.com> > > > > What #define do I change and were to get some more pages for Disc I/O? > > I can't write a large amount of data to a raw SCSI device for testing. > > I use the BusLogic driver. It gets memory for "DMA" from the kernel. > > It runs out and hangs. > > > > The BusLogic driver itself should never hang waiting for DMA memory. The only > > place it asks for memory after initialization is if it decides to expand the > > number of CCBs. In that case, it calls with GFP_ATOMIC and should handle not > > being able to create any. > > > > I would think the DMA memory allocations are coming from the SCSI disk driver > > itself (sd.c). I think there are some magic files in /proc that can reserve > > more free pages, but I've never tried them. > > Okay. I'll check some more. I am trying to isolate a possible file-system > problem that occurs with _VERY_LARGE_ files. To isolate specific file-systems > I am trying to write to a raw SCSI device just to make sure I can read > what I write, i.e., is it a driver problem instead of a file-system problem. > So far, I can't write directly to the raw device without a "free-page" hang. > > This may not be a problem in the "real" world because the kernel will get > a chance to free up FS buffers to make more free pages. However, when I > don't have the file-system cache, the SCSI interface has got to have > enough buffers to fill it's cached-write SCB queue.
I notice this happens a lot with mke2fs and large drives.
Usually, the system will un-hang once I make another process start or stop or do some memory de(allocation).
Other than this, I don't have much information. =/
Jason Duerstock jason@linux.aatech.com
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