On Sun, Jun 7, 2009 at 10:13 AM, Ingo Molnar <mingo@xxxxxxx> wrote: > * Joerg Roedel <joerg.roedel@xxxxxxx> wrote: >> But its up to Linus/Ingo to decide if it can be accepted at this >> very late point in the cycle. Since dma-debug is new with 2.6.30 >> it will at least not introduce any regression. [...] > > I think it's too late for v2.6.30 to do any of the changes - and the > DMA debug facility is off by default. > > Also, i think such DMA patterns, while 'allowed' can be quite > dangerous as its such a rare usage combination really. AIO and DIO > are crazy to begin with, mixing AIO and DIO for the same buffer is > madness square two. (It can result in 3 agents for the same memory > address: CPU, dma1 and dma2. How many interesting chipset erratums > could there be related to such scenarios?) I think in my case the cause is somewhat simpler: RAID1 My root filesystem is on a RAID1 that consists of two disks, both connected to the sata_sil24 controller. So it is only natural for the md driver to issue two dma read requests for the same address: one for each drive. Torsten -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
