> -----Original Message----- > From: Russell King - ARM Linux [mailto:linux@xxxxxxxxxxxxxxxx] > Sent: Monday, December 21, 2009 2:38 PM > To: Hiremath, Vaibhav > Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; linux-mm@xxxxxxxxx; linux- > omap@xxxxxxxxxxxxxxx > Subject: Re: CPU consumption is going as high as 95% on ARM Cortex > A8 > > On Mon, Dec 21, 2009 at 11:56:23AM +0530, Hiremath, Vaibhav wrote: > > > vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); > > > > > > will result in the memory being mapped as 'Strongly Ordered', > > > resulting > > > in there being multiple mappings with differing types. In later > > > kernels, we have pgprot_dmacoherent() and I'd suggest changing > the > > > above > > > macro for that. > > > > > > > I tried with your suggestion above but unfortunately it didn't > work for > > me. I am seeing the same behavior with the pgprot_dmacoherent(). I > > pulled your patch (which got applied cleanly on 2.6.32-rc5) - > > What happens if you comment out the pgprot_dmacoherent() / > pgprot_noncached() > line completely? > [Hiremath, Vaibhav] If I comment the line completely then I am seeing CPU consumption similar to when I was setting PAGE_READONLY/PAGE_SHARED flag, which is 25-32%. Thanks, Vaibhav > I suspect that will "solve" the problem - but you'll then no longer > have > DMA coherency with userspace, so its not really a solution. -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
