Thread (35 messages) 35 messages, 6 authors, 2022-12-07

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

From: David Laight <hidden>
Date: 2022-11-02 12:01:23
Also in: live-patching, lkml

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

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