After upgrading Redhat to 8.8, the reserved memory has expanded.
Therefore, depending on the implementation of total memory, you need to pay attention to this change.
Taking the output of 4G memory as an example, the reserved of the two versions has changed significantly. Added about 70M of reserved memory.
Memory: 2901108K/4193728K available (12293K kernel code, 5878K rwdata, 8376K rodata, 2552K init, 14256K bss, 442992K reserved, 0K cma-reserved) Memory: 2886708K/4193K728K 892K rwdata, 8464K rodata, 2596K
init , 14140K bss, 510876K reserved, 0K cma-reserved)
Through the analysis, it is more reserved when doing crashkernel.
dmsg:[ 0.000000] Reserving 256MB of memory at 2800MB for crashkernel (System RAM: 8191MB)
dmsg.old:[ 0.000000] Reserving 192MB of memory at 2864MB for crashkernel (System RAM: 8191MB)
https://lore.kernel.org/lkml/YgOGPbdtQIhPNen7@MiWiFi-R3L-srv/T/
ck_cmdline = “1G-4G:192M,4G-64G:256M,64G-:512M”;
ck_cmdline = “1G-4G:160M,4G-64G:192M,64G-1T:256M,1T-:512M”;
- crash_core: Increase crashkernel=auto size for x86_64, s390 and arm64 (Lichen Liu) [2122874]