magicse
commented
3 months ago Also i try experiment in emulation on x86 like this. And get different strange things Alpine Linux 3.18.0 under emulation page size 32k work but give me page size 4K
getconf PAGESIZE
4096Alpine Linux 3.17.0 under emulation page size 32k give me "bin/sh: getconf: Bad address"
on any commands.
And backward on QNAP with pagesize 32K container Alpine Linux 3.17.0 work without problem and Alpine Linux 3.18.0 didnt work at all.
sudo apt-get install qemu binfmt-support qemu-user-static
docker run --rm --privileged multiarch/qemu-user-static --reset -p yes
for 32K PAGE SIZE
docker run -e "QEMU_CPU=cortex-a15" -e "QEMU_PAGESIZE=32768" --rm --platform linux/arm/v7 -it alpine:3.17.0 /bin/sh
docker run -e "QEMU_CPU=cortex-a15" -e "QEMU_PAGESIZE=32768" --rm --platform linux/arm/v7 -it alpine:3.18.0 /bin/sh
for 4K PAGE SIZE
docker run -e "QEMU_CPU=cortex-a15" -e "QEMU_PAGESIZE=4096" --rm --platform linux/arm/v7 -it alpine:3.17.0 /bin/sh
docker run -e "QEMU_CPU=cortex-a15" -e "QEMU_PAGESIZE=4096" --rm --platform linux/arm/v7 -it alpine:3.18.0 /bin/sh
Oficial Last Alpine image get exit code 139 (ala sigfault) i think due 4K - 32K Page size mismatches for some libraries or applications in the image.
Alpine image 3.17 work well.
QNAP TS-231P3 (Alpine AL314 armv7) Container Station PageSize 32K Page size 32K - QNAP change Page size from 4K to 32 K
Also i found information about Page Size 32K for arm32v7
On ARM based NAS it is possible to have storage volume larger than 16TB, especially with the use of LVM. However, on 32-bit architectures, the page cache index is stored on 32 bits, which means that given a page size of 4 KB, we can only address volumes of up to 16 TB.
Therefore, one option to use such large volumes and filesystems on 32 bits architecture is to increase the page size.
This series allows to support 8K, 16K, 32K and 64K kernel pages. On ARM the size of the page can be either 4K or 64K, so for the other size a "software emulation" is used, here Linux thinks it is using pages of 8 KB, 16 KB or 32 KB, while underneath the MMU still uses 4 KB pages.
For ARM there is already a difference between the kernel page and the hardware page in the way they are managed. In the same 4K space the Linux kernel deals with 2 PTE tables at the beginning, while the hardware deals with 2 other hardware PTE tables.
This series takes advantage of it and pushes further the difference between hardware and Linux version by using larger page size at Linux kernel level. https://lwn.net/Articles/822868/