** Description changed: [Impact] Running the current armhf raspi kernel on Pi 3 and 2 results in wasting ~70MB of memory because of LPAE, HIGHMEM and VMSPLIT_3G. That's a - significant waste of memory particularly on a Pi 3A+ which only has - 512MB to begin with. Additionally, with HIGHMEM enabled, CMA memory is - allocated from the highmem zone which is too small to provide the + significant amount of lost memory particularly on a Pi 3A+ which only + has 512MB to begin with. Additionally, with HIGHMEM enabled, CMA memory + is allocated from the highmem zone which is too small to provide the default 256MB for CMA. [Test Case] On a Pi 3B: $ dmesg | grep cma-reserved [0.000000] Memory: 778696K/970752K available (12288K kernel code, 821K rwdata, 4088K rodata, 2048K init, 786K bss, 126520K reserved, 65536K cma-reserved, 118784K highmem) + + A test kernel without LPAE and HIGHMEM on a Pi 3B: + $ dmesg | grep cma-reserved + [0.000000] Memory: 848400K/970752K available (12288K kernel code, 811K rwdata, 4056K rodata, 1024K init, 761K bss, 56816K reserved, 65536K cma-reserved) + [Regression Potential] - There should be no impact to users of the current flavor, which - continues to be the default (for now). + None that I can think of at the moment.
-- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1896761 Title: Provide a raspi-nolpae kernel flavor To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux-raspi/+bug/1896761/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
