Hi Nishant, I am facing the same problem to allocate a chunk of 4MB on omap3evm using dma_alloc_coherent. I used the test driver mentioned here http://www.mail-archive.com/linux-omap@vger.kernel.org/msg11074.html
I applied the patch for ioremap(24f11ec001920f1cfaeeed8e8b55725d900bbb56) suggested by Russell, but stiill seeing the error saying coherent allocation too big (requested 0x400000 mask 0xffffffff) alloc[0] - virt=0x00000000 phy=0xFFFFFFFF size=0x00400000 Allocation failed idx=0 insmod: cannot insert `dummy.ko': Cannot allocate memory (-1): Cannot allocate memory I changed the GFP_KERNEL to GFP_TEMPORARY and also to (GFP_KERNEL | __GFP_RECLAIMABLE), but failed to insmod the module. I am working on linux-omap 2.6.28 kernel. Even I could not allocate memory size greater than 1MB. Has this been fixed? Are there any patches to fix this issue? On Thu, Mar 19, 2009 at 2:36 PM, Menon, Nishanth <n...@ti.com> wrote: > Hi Hiroshi, >> -----Original Message----- >> From: Hiroshi DOYU [mailto:hiroshi.d...@nokia.com] >> Sent: Thursday, March 19, 2009 8:43 AM > >> >> >> What would happen with __GFP_RECLAIMABLE for dma_alloc_coherent()? > As per [1], GFP_TEMPORARY might be the right approach.. but yes, > Changing dummy to do: > dma_alloc_coherent(NULL, b[i].size, &b[i].phy, GFP_TEMPORARY); > > Seems to resolve the issue with the dummy driver. > > The question however still remains: For a driver to allocate a memory which > is not temporary in nature we'd recommend GFP_KERNEL. But as part of the exit > sequence the driver will deallocate that memory and as part of init sequence, > reallocate. Given that the memory is not reclaimed immediately, it looks like > the only way to ensure that would be to do GFP_KERNEL | __GFP_RECLAIMABLE > (which essentially is the definition of GFP_TEMPORARY). > > Regards, > Nishanth Menon > Ref: > [1] http://lkml.indiana.edu/hypermail/linux/kernel/0705.2/0638.html > -- > To unsubscribe from this list: send the line "unsubscribe linux-omap" in > the body of a message to majord...@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- Best Regards Pramod -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
