Messages in this thread |  | | | Date | Mon, 10 Mar 1997 14:59:04 -0500 (EST) | | From | "Richard B. Johnson" <> | | Subject | Re: Couldn't get a free page |
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On Mon, 10 Mar 1997, Leonard N. Zubkoff wrote:
> Date: Mon, 10 Mar 1997 09:18:47 -0500 (EST) > From: "Richard B. Johnson" <root@analogic.com> > > Hello memory manager wizards........ > > 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. > > Leonard
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. >
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