On Tue, Jul 28, 2009 at 7:06 AM, Vipul Jain<vipulsj@xxxxxxxxx> wrote: > Hi Deepak, > > I am newbie too but to my understanding kernel memory is divided into > following memory zones: > DMA_ZONE > NORMAL_ZONE > HIGHMEM_ZONE > > and depending on arch of the machine these memory zone range gets > defined. e.g. for x86 its 16MB > (24bit ISA address space) and on other platforms say ARM both DMA and > NORMAL can be same. hence > kernel assigns its addressable address from 0 to 2^32 address into these > different memory zones and > provides helper functions to request memory from these regions. > > I am not sure if these ZONES can be changed as per requirement say making > x86 DMA zone more than > 16 MB. May be linux gurus on this alias could put more light on this. > > Regards, > Vipul. > > > > On Mon, Jul 27, 2009 at 6:21 AM, Deepak Vishwakarma > <vishwakarma.deepak@xxxxxxxxx> wrote: >> >> Hi guyz, >> >> Need your favour! >> >> How is DMA memory is allocated in kernel space? And how can it be >> increased? If your requirement is less than 128k, you can use kmalloc with GFP_DMA. Otherwise use, get_free_pages() and directly you can use these pages for DMA. You can allocate max 4M using this. >> >> Regards, >> Deepak > > -- To unsubscribe from this list: send an email with "unsubscribe kernelnewbies" to ecartis@xxxxxxxxxxxx Please read the FAQ at http://kernelnewbies.org/FAQ
