Re: uncached page allocator

2007-08-30 Thread Nick Piggin
Peter Zijlstra wrote: On Tue, 2007-08-21 at 16:05 +1000, Dave Airlie wrote: So you can see why some sort of uncached+writecombined page cache would be useful, I could just allocate a bunch of pages at startup as uncached+writecombined, and allocate pixmaps from them and when I bind/free the

Re: uncached page allocator

2007-08-28 Thread Christoph Lameter
There is an uncached allocator in IA64 arch code (linux/arch/ia64/kernel/uncached.c). Maybe having a look at that will help? Jes wrote it. - This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to

Re: uncached page allocator

2007-08-21 Thread Dave Airlie
Blame intel ;) Any other ideas and suggestions? Without knowing exactly what you are doing: - Copies to uncached memory are very expensive on an x86 processor (so it might be faster not to write and flush) - Its not clear from your description how intelligent your transfer system is.

Re: uncached page allocator

2007-08-21 Thread Peter Zijlstra
On Tue, 2007-08-21 at 16:05 +1000, Dave Airlie wrote: So you can see why some sort of uncached+writecombined page cache would be useful, I could just allocate a bunch of pages at startup as uncached+writecombined, and allocate pixmaps from them and when I bind/free the pixmap I don't need the

Re: uncached page allocator

2007-08-20 Thread Alan Cox
allocate pixmap gets cached memory copy data into the pixmap pre-use from hardware we flush the cache lines and tlb use the pixmap in hardware pre-free we need to set the page back to cached so we flush the tlb free the memory. Now the big issue here on SMP is that the cache and/or tlb

uncached page allocator

2007-08-19 Thread Dave Airlie
Hi all, I've started doing some work with using the new DRM memory manager from TG for pixmaps in the X server using Intel 9xx series hardware. The intel hardware pretty much requires pages to be uncached for the GPU to access them. It can use cached memory for some operations but it isn't very