On Mon, Jan 05, 2015 at 03:52:10PM +0000, One Thousand Gnomes wrote: > > I tried in all ways to implement this with mmap(), but it does not success, > > because I did not find a way to mmap() file as O_WRONLY. Mapping as O_RDWR > > makes kernel to pre-fill mapped memory with partition data. So, kernel and > > DMA actually compete on the RAM area to fill it - one with garbage, one > > with actual data. Kernel wins. > > > > So, how to implement Linus's advice? > > Use O_DIRECT. There are lots of problems with the mmap() model, in > particular with how mmu table changes scale to large numbers of CPU > threads (ie they don't).
They do. Kinda. See split page table lock. But, yeah, mmap() approach should not be faster anyway. -- Kirill A. Shutemov -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
