Hello, I was doing some research figuring out what kernel reserves memory for, and found myself in a sort of dead-end. I found out that /proc/kpageflags bit 32 is set for reserved physical pages in include/linux/kernel-page-flags.c, wrote a simple decoder of that file, and on an old 32-bit x86 machine (it's the simplest there, since it has less memory and fewest amount of memory holes) those are reserved: 0x00000000-0x0000ffff - I assume those addresses are used for interrupt vectors and whatnot 0x0009b000-0x000fffff - Video RAM/ROM for VGA/EGA/CGA and whatnot 0x01c00000-0x01c1ffff - no idea, it also has KPF_UNCACHED flag as well 0x1d000000-0x1dd73fff - Kernel code, rodata, rwdata, bss 0x35b4a000-0x36b55fff - no idea. I also found out that region #5 is getting bigger or smaller depending on the machine's memory size. On this 1.5G machine it's a bit more than 16M. On a 32G machine it's more than 500M size, feels a bit wasteful IMO. So my question is, could you tell me where to look for what those regions are and why those regions exist? I've checked /proc/iomem and it doesn't say it is reserved or anything, just "System RAM". Thanks in advance, Mikhail.
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