Messages in this thread |  | | Subject | Re: mm: critical shortage of bounce buffers | Date | Fri, 28 Sep 2001 23:16:16 +0100 (BST) | From | Alan Cox <> |
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> > Its in the high mem handling routines. It means the machine stalled for > > a moment doing I/O because it had no memory below 1Gb to use. > > But why does it need to have memory below 1Gb ?? Normally, 32bit PCI DMA > controllers (such as network cards and disk controllers) can access up to 4GB of > physical memory within the machine, so unless you are using the CONFIG_HIGHMEM4G > option it shouldn't need bounce buffers. Or am I missing something here > (something like the second physical GB is actually in the address range > 4GB->)???
The core code doesn't know if the device is PIO or DMA, and it cannot pass virtually unmapped objects to the block layer. This is what Jens has been fixing.
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