RE: [PATCH v8 4/9] kallsyms: Reduce the memory occupied by kallsyms_seqs_of_names[]

[David Laight]

From: Zhen Lei
> Sent: 02 November 2022 08:49
> 
> kallsyms_seqs_of_names[] records the symbol index sorted by address, the
> maximum value in kallsyms_seqs_of_names[] is the number of symbols. And
> 2^24 = 16777216, which means that three bytes are enough to store the
> index. This can help us save (1 * kallsyms_num_syms) bytes of memory.

You can get the compiler to do the 'heavy lifting' for you.

struct uint24 {
    unsigned int val24:24;
} __attribute__((packed));

struct uint24 table[1024];

works fine.

	David

-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)