Messages in this thread | | | Date | Fri, 03 Sep 1999 01:25:06 +0200 | From | Manfred Spraul <> | Subject | Re: CONFIG_BIGMEM and rawio |
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"Stephen C. Tweedie" wrote: > Exactly why it needs to be per-device. Once the high memory limit is > raised above 4G, this will become even more important as not all devices > will physically be able to support 64-bit PCI addressing.
I doubt that bounce buffers are necessary for 4 GB: * most fast disk controllers use DMA * noone would combine a 4 GB memory computer with an old IDE disk.
But perhaps you should add them for 64-bit PCI.
Btw, if you add per-device flags, please add a central "block device busy"-flag: * raw-io does not set the blocksize for VFS mounts, but it ignores md volumes and swap partitions. * "mount -t ext2 /dev/swappartition" makes swapping unstable. * an accidential "swapon /dev/root" makes the root volume unusable: ext2 tries to read 1024 bytes, but the sector size was switched to 4096.
-- Manfred
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