Public bug reported: [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 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) [Regression Potential] There should be no impact to users of the current flavor, which continues to be the default (for now). ** Affects: linux-raspi (Ubuntu) Importance: Undecided Status: Triaged ** Affects: linux-raspi (Ubuntu Groovy) Importance: Undecided Status: Triaged ** Package changed: linux-raspi2 (Ubuntu) => linux-raspi (Ubuntu) ** Also affects: linux-raspi (Ubuntu Groovy) Importance: Undecided Status: New ** Changed in: linux-raspi (Ubuntu Groovy) Status: New => Triaged -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux-raspi2 in Ubuntu. https://bugs.launchpad.net/bugs/1896761 Title: Provide a raspi-nolpae kernel flavor Status in linux-raspi package in Ubuntu: Triaged Status in linux-raspi source package in Groovy: Triaged Bug description: [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 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) [Regression Potential] There should be no impact to users of the current flavor, which continues to be the default (for now). To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux-raspi/+bug/1896761/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp