Re: KLD mmap question
On Thu, 30 May 2002, Tom Tang wrote: > Thanks for the reply, I'll check it out. However > if you'll notice in my prev mail, I stated that I was > trying to contigmalloc 4K... Hard to believe that > the system doesnt have 4K lying around. Good point. Contigmallocing a page is pretty silly, since you get a page anyway. Why not just use normal malloc? Doug White| FreeBSD: The Power to Serve [EMAIL PROTECTED] | www.FreeBSD.org To Unsubscribe: send mail to [EMAIL PROTECTED] with "unsubscribe freebsd-hackers" in the body of the message
Re: KLD mmap question
On Thu, 2002-05-30 at 13:14, Tom Tang wrote: > Hello, > > I have a question about implementing mmap functions in > device drivers. Thinking it would be simple, I contigmalloc'd > a buffer of PAGE_SIZE and returned it using atop like other > mmap device implementations. However when my userland program > mmaps the device with offset 0, when I try accessing the returned > pointer, it returns me invalid memory address. Any help would > be appreciated... An associated question: while I was looking at the DRM's mmap for the shared memory area, I think I figured out that you didn't need memory that was going to be mmapped to be physically contiguous (since the device pager would get each page of it separately). Was I right? -- Eric Anholt <[EMAIL PROTECTED]> http://gladstone.uoregon.edu/~eanholt/dri/ To Unsubscribe: send mail to [EMAIL PROTECTED] with "unsubscribe freebsd-hackers" in the body of the message
Re: KLD mmap question
Doug, Thanks for the reply, I'll check it out. However if you'll notice in my prev mail, I stated that I was trying to contigmalloc 4K... Hard to believe that the system doesnt have 4K lying around. - Tom On Thu, 30 May 2002, Doug White wrote: > On Thu, 30 May 2002, Tom Tang wrote: > > > I have a question about implementing mmap functions in > > device drivers. Thinking it would be simple, I contigmalloc'd > > a buffer of PAGE_SIZE and returned it using atop like other > > mmap device implementations. However when my userland program > > mmaps the device with offset 0, when I try accessing the returned > > pointer, it returns me invalid memory address. Any help would > > be appreciated... > > Generally, after the machine is started, memory gets too fragmented to use > contigmalloc. > > If you preload the module and do the contigmalloc at attach time it should > succeed. > > Doug White| FreeBSD: The Power to Serve > [EMAIL PROTECTED] | www.FreeBSD.org > > -- Tom Tang [EMAIL PROTECTED] To Unsubscribe: send mail to [EMAIL PROTECTED] with "unsubscribe freebsd-hackers" in the body of the message
Re: KLD mmap question
On Thu, 30 May 2002, Tom Tang wrote: > I have a question about implementing mmap functions in > device drivers. Thinking it would be simple, I contigmalloc'd > a buffer of PAGE_SIZE and returned it using atop like other > mmap device implementations. However when my userland program > mmaps the device with offset 0, when I try accessing the returned > pointer, it returns me invalid memory address. Any help would > be appreciated... Generally, after the machine is started, memory gets too fragmented to use contigmalloc. If you preload the module and do the contigmalloc at attach time it should succeed. Doug White| FreeBSD: The Power to Serve [EMAIL PROTECTED] | www.FreeBSD.org To Unsubscribe: send mail to [EMAIL PROTECTED] with "unsubscribe freebsd-hackers" in the body of the message
